DDJ-400 DJ Controller Service Manual (QRT1023)

ORDER NO.
QRT1023
DDJ-400
DJ CONTROLLER
DDJ-400
THIS MANUAL IS APPLICABLE TO THE FOLLOWING MODEL(S) AND TYPE(S).
Model Type Power Requirement Remarks
DDJ-400 SXJ DC 5 V (USB bus power only)
DDJ-400 XJCN DC 5 V (USB bus power only)
THIS SERVICE MANUAL SHOULD BE USED TOGETHER WITH THE FOLLOWING MANUAL(S).
Model Order No. Remarks
DDJ-400 QRT1024 SCHEMATIC DIAGRAM, PCB CONNECTION DIAGRAM, PCB PARTS LIST
Pioneer DJ Corporation 6F, Yokohama i-Mark Place, 4-4-5 Minatomirai, Nishi-ku, Yokohama, Kanagawa 220-0012 Japan
2018 Pioneer DJ Corporation

1 2 3 4
SAFETY INFORMATION
This service manual is intended for qualified service technicians; it is not meant for the casual do-it-
yourselfer. Qualified technicians have the necessary test equipment and tools, and have been trained
to properly and safely repair complex products such as those covered by this manual.
Improperly performed repairs can adversely affect the safety and reliability of the product and may
void the warranty. If you are not qualified to perform the repair of this product properly and safely, you
should not risk trying to do so and refer the repair to a qualified service technician.
B CAUTION
Since the fuse may be in the neutral of the mains supply, disconnect the mains to de-energize the phase conductors.
2 DDJ-400
1 2 3 4
5 6 7 8
CONTENTS
SAFETY INFORMATION.......................................................................................................................................................... 2
1. SERVICE PRECAUTIONS .................................................................................................................................................... 4
1.1 NOTES ON SOLDERING ............................................................................................................................................... 4 A
1.2 NOTES ON REPLACING ............................................................................................................................................... 4
1.3 SERVICE NOTICE.......................................................................................................................................................... 4
2. SPECIFICATIONS................................................................................................................................................................. 5
2.1 ACCESORIES ................................................................................................................................................................ 5
2.2 SPECIFICATIONS .......................................................................................................................................................... 5
3. BASIC ITEMS FOR SERVICE .............................................................................................................................................. 6
3.1 CHECK POINTS AFTER SERVICING ........................................................................................................................... 6
3.2 JIGS LIST ....................................................................................................................................................................... 6
3.3 PCB LOCATIONS ........................................................................................................................................................... 8
4. BLOCK DIAGRAM ................................................................................................................................................................ 9
4.1 OVERALL WIRING DIAGRAM ....................................................................................................................................... 9
4.2 BLOCK DIAGRAM ........................................................................................................................................................ 10 B
4.3 POWER BLOCK DIAGRAM ......................................................................................................................................... 11
5. DIAGNOSIS ........................................................................................................................................................................ 12
5.1 STARTUP SEQUENCE ................................................................................................................................................ 12
5.2 TROUBLESHOOTING.................................................................................................................................................. 14
[0] Prior Confirmation................................................................................................................................................. 14
[1] Failure in Startup (Failure in power-on)................................................................................................................. 14
[2] Display .................................................................................................................................................................. 15
[3] Operations ............................................................................................................................................................ 16
[4] USB connection .................................................................................................................................................... 17
[5] AUDIO OUT .......................................................................................................................................................... 18
[6] AUDIO IN .............................................................................................................................................................. 19
C
5.3 MONITORING OF POWER SUPPLY AND VOLTAGE.................................................................................................. 20
5.4 ABOUT FUNCTION LIMIT MODE AT LOW VOLTAGE................................................................................................. 21
5.5 OPERATION CHECK WITH rekordbox ........................................................................................................................ 22
5.6 ERROR INDICATION.................................................................................................................................................... 24
6. SERVICE MODE ................................................................................................................................................................. 25
6.1 SERVICE MODE .......................................................................................................................................................... 25
6.2 ABOUT THE DEVICE................................................................................................................................................... 33
7. DISASSEMBLY ................................................................................................................................................................... 34
8. EACH SETTING AND ADJUSTMENT ................................................................................................................................ 45
8.1 NECESSARY ITEMS TO BE NOTED........................................................................................................................... 45
8.2 UPDATING OF THE FIRMWARE ................................................................................................................................. 46
8.3 ITEMS FOR WHICH USER SETTING ARE AVAILABLE ............................................................................................. 48 D
9. EXPLODED VIEWS AND PARTS LIST............................................................................................................................... 49
9.1 PACKING SECTION ..................................................................................................................................................... 49
9.2 EXTERIOR SECTION .................................................................................................................................................. 50
DDJ-400 3
5 6 7 8
1 2 3 4
1. SERVICE PRECAUTIONS
1.1 NOTES ON SOLDERING
• For environmental protection, lead-free solder is used on the printed circuit boards mounted in this unit.
A Be sure to use lead-free solder and a soldering iron that can meet specifications for use with lead-free solders for repairs
accompanied by reworking of soldering.
Do NOT use a soldering iron whose tip temperature cannot be controlled.
1.2 NOTES ON REPLACING

Parts that is defficult to replace
The part listed below is difficult to replace as a discrete component part.
It the failure of suspected that are listed in the table, replace whole ASSY.
ASSY Name
Ref. No Part No. Function Remarks
B
CN101 VKN2097 FFC CONNECTOR Terminal part with through-hole
CN102 VKN1262 FFC CONNECTOR Terminal part with through-hole
MAIN ASSY CN103 VKN1256 FFC CONNECTOR Terminal part with through-hole
JA101 DKN1237 USB-B JACK Terminal part with through-hole
JA702 AKB7181 MASTER OUTPUT RCA JACK Terminal part with through-hole
Lubrication during Reassembly of the Jog Dial

When reassembling the Jog Dial after replacing the Jog Dial or Control Panel, be sure to apply grease to the shaft and shaft
bearing of the Jog Dial.
For details on how to lubricate, see "Procedure for applying grease during reassembly of the Jog Dial" in "7. DISASSEMBLY."
Be sure to use the specified grease.
C
Parts that require simultaneous replacement
Two photointerrupters are provided for detection of Jog Dial rotations.
When replacement of photointerrupters is required because of abnormalities in detected waveforms, etc., be sure to replace
both photointerrupters at the same time.
Corresponding Part No.: RPI-579N1
Parts that require simultaneous replacement: PC1201, PC1202 (DCK1 ASSY) / PC2401, PC2402 (PNL2 ASSY)
After replacement, confirm it is correctly attached according "6-1. SERVICE MODE : -3 Photo interrupter check mode ."
1.3 SERVICE NOTICE

D Monitoring of power supply and voltage
This unit always monitors for power supply and voltage.
After an error is detected, this unit will shut itself off immediately and all indicators are turned off.
After the unit shuts itself off because of an error, the defective point may produce heat, which may be dangerous.
Therefore, disconnect the USB cable and wait for a while before turning the unit back on.
Repair the unit according to the diagnostic procedures described in “5.3 MONITORING OF POWER SUPPLY AND VOLTAGE.”
Demo Mode
This unit will automatically enter demo mode if it is left unoperated for 10 minutes in normal operation mode.
To cancel this mode, operate any control or button of this unit.
The default setting of time to switch to the demo mode is 10 minutes.
E Demo mode can be invalidated or it’s possible to change time until start demo mode in the setting of utilities mode.
(For details, refer to the operating instructions)
4 DDJ-400
1 2 3 4
5 6 7 8
How to modify when rattling of product is occurred

Place the blocks at 8 points ( ) under the control panel (Height more than 25 mm and Diameter I lower than 30 mm is
recommended), and attach the chassis part according to the screw tightening order manually.
(The block is available at the home center, etc)(Refer to "7 DISASSEMBLY" about the screw tightening order.) A
When there is no block, place the whole surface of the control panel to the curing mat, and attach the chassis part according
to the screw tightening order manually.
Take care not to press the screwdriver strongly to the product in any case.
Do not use the electric screwdriver.
Paste Acetate Tape on the back face of PCB

When Acetate Tape is peeled off during PCB replacement and repair.
Perform paste of new Acetate Tape.
(Position : Paste into silk frame of PCB)
Acetate Tape Acetate Tape C
PNL2 ASSY DCK1 ASSY
2. SPECIFICATIONS
2.1 ACCESORIES D
• USB cable (DDE1150) *1 : The included warranty is for the European region.
— For the North American region, the corresponding information is
• Operating instructions (SXJ : DRH1505)
provided on the last page of both the English and French
(Quick start guide) (XJCN : DRH1506)
versions of the “Operating Instructions (Quick Start Guide)”.
• Warranty (SXJ only) — For the Japanese region, the corresponding information is
• Warranty (for some regions) *1 provided on the back cover of the “Operating Instructions
(Quick Start Guide)”.
2.2 SPECIFICATIONS
General – Main Unit
Power supply .........................................................................................DC 5 V Input impedance
E
Rated current ....................................................................................... 500 mA MIC ......................................................................................3 k : or higher
Main unit weight . ........................................................................ 2.1 kg (4.6 lb) Output impedance
Max. dimensions ........................ 482 mm (W) × 58.5 mm (H) × 272.4 mm (D) MASTER OUT ...................................................... .................. 1 k : or less
(19.0 in. (W) × 2.3 in. (H) × 10.7 in. (D)) HEADPHONES ....................................................................... 10 : or less
Tolerable operating temperature ..............................................+5 °C to +35 °C
Tolerable operating humidity ............................ 5 % to 85 % (no condensation) Input / Output terminals
MIC terminal
Audio Section 1/4” TS jack ......................................................................................... 1 set
Sampling rate .....................................................................................44.1 kHz MASTER OUT output terminal
D/A converter ......................................................................................... 24 bits RCA pin jack ....................................................................................... 1 set
Rated output level/Load impedance HEADPHONES output terminal
MASTER OUT ................................................................... 2.1 Vrms/10 k : 3.5 mm stereo mini jack ...................................................................... 1 set
Frequency characteristic USB terminal
USB ................................................................................... 20 Hz to 20 kHz B type .................................................................................................. 1 set
S/N ratio (rated output, A-WEIGHTED) F
USB ................................................................................................. 103 dB • The specifications and design of this product are subject to change
Total harmonic distortion without notice.
USB ................................................................................................ 0.005 % • © 2018 Pioneer DJ Corporation. All rights reserved.
DDJ-400 5
5 6 7 8
1 2 3 4
3. BASIC ITEMS FOR SERVICE

3.1 CHECK POINTS AFTER SERVICING
To keep the product quality after servicing, confirm recommended check points shown below.
A
No. Procedures Check points
1 Check the firmware version in Service Mode. The version of the firmware must be the latest.
(The firmware version can be checked on PC/Mac. Update firmware to the latest one, if it is not the lasted.
-> Refer to 8.2 UPDATING OF THE FIRMWARE)
2 Confirm whether the customer complaint has been resolved. The customer compain must not be reppeared.
If the problem pointed out by the customer occurs with a specific Audio and operations must be normal.
source or operation, such as PC input, MIC input, Fader, or VOL,
input that specific source then perform that specific operation for
checking.
3 Check the each operation. There must be no errors in operations of each button, jog dial,
Enter Service mode. LEDs, VOL, fader control, and rotary encoder.
B 4 Check the analog audio output. Audio and operations of MASTER output / HEADPHONE output
Connect this unit to a PC/Mac with the DJ application (rekordbox must be normal (Not noise etc.).
DJ) installed, via USB, then play back audio.
5 Check the analog audio input. Audio and operations must be normal.
Input an audio signal via MIC.
6 Check the appearance of the product. No scratches or dirt on its appearance after receiving it for service.
See the table below for the items to be checked regarding audio.
Item to be checked regarding audio
Distortion Volume too high
C Noise Volume fluctuating

Volume too low Sound interrupted
3.2 JIGS LIST

Jigs List
Jig Name Part No. Purpose of use / Remarks
USB cable GGP1193 For PC connection
License-key card for Service GGP1522 For activation of rekordbox dj
D
Lubricants and Glues List

Name Part No. Remarks
Acetate Cloth Tape GYH1001 Refer to 1.3 SERVICE NOTICE : Paste Acetate Tape on the back
face of PCB.
Grease GEM1100 Refer to “7. DISASSEMBLY : [4-1] Procedure for applying grease
during reassembly of the Jog Dial”
6 DDJ-400
1 2 3 4
MODE CHECK OBJECT OPERATION POINT / SETTING INDICATION POINT STATE CHECK
CONTENTS
SEVICE CHECK SHEET

Version Firmware [1st column]
Left/Right DECK:[HOT CUE][BEAT LOOP]
[BEAT JUMP][SAMPLER]
[2nd column]
Left/Right DECK:PAD Upper section Ver.
Right DECK:CUE
[3rd column]
Left/Right DECK:PAD Lower section
Right DECK:PLAY/PAUSE
Operating All LED light on Browser section ROTARY SELECTOR All LED Light on by pressing button
Element All LED dimmer ROTARY SELECTOR All LED Dimmer out by pressing button
5
5
out
All LED light off ROTARY SELECTOR All LED Light off by pressing button
Push SW Deck section IN/4BEAT Left/Right IN/4BEAT Left/Right Light on by pressing button, Light off by releasing button /
(With LED) OUT Left/Right OUT Left/Right Light on by pressing button, Light off by releasing button /
RELOOP EXIT Left/Right RELOOP EXIT Left/Right Light on by pressing button, Light off by releasing button /
BEAT SYNC Left/Right BEAT SYNC Left/Right Light on by pressing button, Light off by releasing button /
CUE Left/Right CUE Left/Right Light on by pressing button, Light off by releasing button /
PLAY/PAUSE Left/Right PLAY/PAUSE Left/Right Light on by pressing button, Light off by releasing button /
HOT CUE mode Left/Right HOT CUE mode Left/Right Light on by pressing button, Light off by releasing button /
BEAT LOOP mode Left/Right BEAT LOOP mode Left/Right Light on by pressing button, Light off by releasing button /
BEAT JUMP mode Left/Right BEAT JUMP mode Left/Right Light on by pressing button, Light off by releasing button /
SAMPLER mode Left/Right SAMPLER mode Left/Right Light on by pressing button, Light off by releasing button /
Perfomance PAD1 Left/Right Perfomance PAD1 Left/Right Light on by pressing button, Light off by releasing button /
6
6
SERVICE MODE 1
Mixer section HEADPHONES CUE Master HEADPHONES CUE Master Light on by pressing button, Light off by releasing button
HEADPHONES CUE CH 1/2 HEADPHONES CUE CH 1/2 Light on by pressing button, Light off by releasing button /
Effect section BEAT FX ON/OFF BEAT FX ON/OFF Light on by pressing button, Light off by releasing button
DDJ-400
Push SW Browser section ROTARY SELECTOR All LED Repeat in order of light on => dimmer out => light off by
(Without LED) pressing button
LOAD Left/Right CUE Left/Right Light on by pressing button, Light off by releasing button /
Deck section SHIFT Left/Right None *1 /
JOG(TOUCH) Left/Right PLAY/PAUSE Left/Right Light on by pressing button, Light off by releasing button /
CUE/LOOP CALL Left/Right IN/4BEAT Left/Right Light on by pressing button, Light off by releasing button /
CUE/LOOP CALL Left/Right OUT Left/Right Light on by pressing button, Light off by releasing button /
Effect section BEAT HEADPHONES CUE CH1/2 Light on by pressing button, Light off by releasing button /
FX SELECT HEADPHONES CUE Master Light on by pressing button, Light off by releasing button
Volume [TYPE A]
7
7
operation Browser section ROTARY SELECTOR Perfomance PAD (Eight PAD) Lighting point of LED in PAD moves acccording to rotation motion
Deck section JOG dial Left/Right Perfomance PAD (Eight PAD) Left/Right Lighting point of LED in PAD moves acccording to rotation motion /
[TYPE B]
Deck section TEMPO slider Left/Right CHANNEL LEVEL INDICATOR Left/Right Indicator display changes according to position of VR /
Mixer section TRIM CH1/CH2 Indicator display changes according to position of VR /
EQ HI CH1/CH2 Indicator display changes according to position of VR /
EQ MID CH1/CH2 Indicator display changes according to position of VR /
EQ LOW CH1/CH2 Indicator display changes according to position of VR /
FILTER CH1/CH2 Indicator display changes according to position of VR /
Channel fader CH1/CH2 Indicator display changes according to position of VR /
[TYPE C]
Effect section BEAT FX LEVEL/DEPTH CHANNEL LEVEL INDICATOR Left+Right Indicator display changes according to position of VR
Mixer section Cross fader Indicator display changes according to position of VR
MASTER LEVEL Indicator display changes according to position of VR
HEADPHONES MIXING Indicator display changes according to position of VR
HEADPHONES LEVEL Indicator display changes according to position of VR
8
8
Slide SW [TYPE D]
Effect section BEAT FX CH SELECT [ H OT C U E ] [ B E AT LO O P ] [ B E AT J U M P ] LED of each button light on and light off according to
Right position of switch (Light off in several seconds after light on)
*1 At the time of all LED light on or all LED dimmer out :
• Previous mode by pressing button (Left DECK)
7
• Next mode by pressing button (Right DECK)

F
A
1 2 3 4
3.3 PCB LOCATIONS

HLD1 ASSY Jog Dial BRWS ASSY MAIN ASSY Jog Dial
A
G E A
C • Bottom view
D F B C
PNL2 ASSY CRFD ASSY HPJK ASSY DCK1 ASSY
Mark No. Description Part No.

LIST OF ASSEMBLIES
D 1..MAIN ASSY DWX4152
NSP 1..PNL1 ASSY DWM2684

2..DCK1 ASSY DWX4153
2..HPJK ASSY DWX4155
2..BRWS ASSY DWX4156
2..CRFD ASSY DWX4157
2..HLD1 ASSY DWX4158
1..PNL2 ASSY DWX4154
8 DDJ-400
1 2 3 4
8 7 6 5
9 DDJ-400
To PC
CN1001 CN101
DDE1150-
VKN2098 VKN2097-A
USB CABLE
V+5LED 39 1 V+5LED
GNDLED 38 2 GNDLED
GNDLED 37 3 GNDLED
DCS1111-
MIC VR
F
LED_IN1 36 4 LED_IN1
VR701
GRID0 35 5 GRID0
LED1 34 6 LED1
GRID1 33 7 GRID1
LED2 32 8 LED2
GRID2 31 9 GRID2
GRID4 30 10 GRID4
GRID3 29 11 GRID3
GRID5 28 12 GRID5
LED_PLAY1 27 13 LED_PLAY1
GRID6 26 14 GRID6
LED_OUT1 25 15 LED_OUT1
GRID7 24 16 GRID7
LED_RELOOP1 23 17 LED_RELOOP1
DKN1669-
KEY3 22 18 KEY3
JA701
MIC JACK
GNDD 21 19 GNDD
WHITE
KEY2 20 20
39P FFC
KEY2
DDD1858-
GNDD 19 21 GNDD
L = 140 mm
SAME FACE
KEY1 18 22 KEY1
AKF7002-A
KN1201
1 GNDD 17 23 GNDD
KEY0 16 24 KEY0
(DWX4153)
TO JOG PLATE
DCK1 ASSY
GNDD 15 25 GNDD
JOG_DIAL1_1 14 26 JOG_DIAL1_1
KEY_IN1 13 27 KEY_IN1
KEY_OUT1 11 29 KEY_OUT1
V+3R3D 10 30 V+3R3D
C C 1/2- C 2/2
KEY_RELOOP1 9 31 KEY_RELOOP1
JOG_TCH1 8 32 JOG_TCH1
GNDD 7 33
L
GNDD
GNDAD 6 34 GNDAD
4. BLOCK DIAGRAM
AD_HPLV 5 35 AD_HPLV
AKB7181-
AD_TEMPO1_1 4 36 AD_TEMPO1_1
MASTER
JA702
AD_HPMX 3 37 AD_HPMX
E
AD_TEMPO1_0 2 38 AD_TEMPO1_0
V+3R3AD 1 39 V+3R3AD
DIP
DIP
VERTICAL
HORIZONTAL
JH101 51048-0500
5 HP_L
4 GNDAH
DKN1237-
USB-Btype
3 HP_R
JA101
USB JACK
2 HP_MUTE
1 GNDAH
JP101
DIP
L = 200mm
To CONTROLLER
LIGHT BLUE
BOARD IN
D20PDY0520E
5P JUMPER WIRE
DIP
2
5
4
3
1
D
52147-0510
HP_L
HP_R
VERTICAL
GNDAH
GNDAH
CN1601
HP_MUTE
JH2001
51048-0500
CN1701 52147-0510
BROWSE_ENC1 1 1 BROWSE_ENC1
(DWX4152)
B HPJK
MAIN ASSY
XKN3017-
JA1601
GNDD 3 3 GNDD
HP MINI JACK
KEY_BRWS 4 4 KEY_BRWS
E BRWS
GRID5 5 5 GRID5
A A 1/4- A 4/4
ASSY
(DWX4155)
DIP
DIP
JP2001
L = 50mm
(DWX4156)
LIGHT BLUE
BOARD IN
VERTICAL
ASSY
D20PDY0505E
5P JUMPER WIRE
CN2001
VKN1256
CN103 VKN1256
F
AD_TRIM1 1 1 AD_TRIM1
CN1801 JH2002 GNDAD 2 2 GNDAD
52147-0510 51048-0500
AD_MLV 3 3 AD_MLV
GNDF 1 1 GNDF AD_HI1 4 4 AD_HI1
GNDAD 2 2 GNDAD AD_TEMPO2-1 5 5 AD_TEMPO2-1
AD_CRFD 3 3 AD_CRFD AD_MID1 6 6 AD_MID1
V+3R3AD 4 4 V+3R3AD AD_TEMPO2-0 7 7 AD_TEMPO2-0
GNDF
C
5 5 GNDF AD_FLTR2 8 8 AD_FLTR2
AD_CRFD 9 9 AD_CRFD
AD_LOW2 10 10 AD_LOW2
AD_HI2 11 11 AD_HI2
DIP
DIP
JP2002
AD_MID2 12 12 AD_MID2
WHITE
L = 50mm
13 13
25P FFC
AD_TRIM2 AD_TRIM2
(DWX4157)
CRFD ASSY
LIGHT BLUE
DDD1859-
BOARD IN
VERTICAL
AD_FXLV 14 14 AD_FXLV
L = 120 mm
D20PDY0505E
AD_CFD1 15 15 AD_CFD1
5P JUMPER WIRE
GNDAD 16 16 GNDAD
REVERSE FACE
AD_CFD2 17 17 AD_CFD2
AD_FLTR1 18 18 AD_FLTR1
AD_LOW1 19 19 AD_LOW1
V+3R3AD 20 20 V+3R3AD
V+3R3AD 21 21 V+3R3AD
GNDD (GNDD_BRWS) 23 23 GNDD
AKF7002-A
KN2401
1 GNDD (GNDD_BRWS) 25 25 GNDD

TO JOG PLATE
DIP
DIP
VERTICAL
VERTICAL
D D 1/2- D 2/2
CN2002 CN102 VKN1262

VKN1262
PNL2 ASSY (DWX4154)
GNDD 1 1 GNDD
JOG_TCH2 2 2 JOG_TCH2
KEY4 3 3 KEY4
V+3R3D 4 4 V+3R3D
B
KEY5 5 5 KEY5
KEY6 7 7 KEY6
GNDD 9 9 GNDD
KEY7 10 10 KEY7
G HLD1
GRID7 11 11 GRID7
KEY8 12 12 KEY8
GRID6 13 13 GRID6
KEY9 14 14 KEY9
GRID5 15 15 GRID5
WHITE
16 16
31P FFC
LED_PLAY2 LED_PLAY2
(DWX4158)
ASSY
DDD1860-
GRID4 17 17 GRID4
L = 170 mm
LED3 18 18 LED3
GNDD 19 19 GNDD
REVERSE FACE
LED4 20 20 LED4
GRID3 21 21 GRID3
LED7 22 22 LED7
GRID2 23 23 GRID2
LED6 24 24 LED6
GRID1 25 25 GRID1
LED5 26 26 LED5
GRID0 27 27 GRID0
GNDLED 28 28 GNDLED
GNDLED 29 29 GNDLED
V+5LED 30 30 V+5LED
V+5LED 31 31 V+5LED
DIP
DIP
VERTICAL
VERTICAL
4.1 OVERALL WIRING DIAGRAM

4. BLOCK DIAGRAM
8 7 6 5
1 2 3 4
4.2 BLOCK DIAGRAM

JA101
USB-B V+VBUS
JACK
A A MAIN ASSY
*Note on DYW****
The “****” part of the part number changes each time the firmware is updated.
VBUS
No Mount
JTAG / JTAG
8
uCOM POWER
IC409 IC202 IC205
S-80927CNMC-G8X / xRST MM3411A33N V+3R3_SH S -1172B1C-U5

Reset IC 1 Reg. Reg.
Q203
5V V+5_D
FET SW LED POWER
IC207 IC204
AUDIO POWER ADC,DAC POWER
V+7
NJM2392M MM1856A50N
-6V DDC.
V-6 IC210
B HP AMP POWER
AMP POWER MM1856A50N
DISCHARGE CIRCUIT
PWR_ON
GPIO /
1
IC211
PWR_ON2
GPIO / KEY,JOG POWER
IC408 1 MM3411A33N
GPIO FAULT_DET VOLTAGE DETECTION Reg.
FLASH MISO0 GPIO / CIRCUIT
DYW **** MOSI0/SSIDATA3 1
(W25Q16JVSSIQ) PSPCK0/SSISCK3
SSL00/SSIWS3 IC209
IC410
TC7SH126FUS1
V_DET VOLTAGE DETECT
GPIO / S-80942CNMC-G9C
(V+VBUS)
FLASH_CS_EN GPIO 1 Reset IC
FLASH_I2S_SEL
GPIO
For USB
X404
XIN
USB_X1 CSS1760-
IC706 MUTE IC701 XOUT 48MHz X'tal
H_DAC_DATA USB_X2
BH3547F
H_DAC_BCK
HP AMP AK4387ET
H_DAC_LRCK
(6dB) HP DAC For AUDIO 48KHz
DAC_MCLK
AUDIO_XOUT X401
XIN
BIAS
IC407 AUDIO_X1
Audio Serial Control
TC74VHC08FK DAC_CDTI DSS1204-

XOUT
B
24.576MHz X'tal
C DAC_xRST AUDIO_X2
HPJK ASSY
DAC_CCLK
DAC_CS(HP_DAC)
DAC_CS(MASTER_DAC) E BRWS ASSY
ROTARY_ENC0, CN103 CN2001 JH2001 CN1701
CN1601 JH101 / HP_AMP_MUTE GPIO ROTARY_ENC1
JA1601 1 GPIO / 24,22 24,22 1,2 1,2
3 3 Mute
/ HP_MUTE 2 Rotary
Encorder
HP mini JACK drive GPIO KEY_BRWS
5 5 1 GPIO / 4 4 /
MUTE IC406 3
MUX_SW_A, V_DET_AD
1
Mute
drive / A_MUTE
GPIO R5S72670P144FP MUX_SW_B,
MUX_SW_C
1
IC703
M_DAC_DATA
MAIN uCom MIXER SECTION
AK4387ET M_DAC_BCK SSITxD0
MUTE SSISCK0 CH1 TRIM
MASTER DAC M_DAC_LRLK IC711
SSIWS0 AD_MUX_0 CH1 HI
/
TC74HC4051AF 1,4,6,19, 1,4,6,19, /
Rotaly CH1 MID
MUX VR CH1 LOW
1 18,3 18,3 6 CH1 FILTER
MASTER VOL
CH2 TRIM
IC712
AD_MUX_1 CH2 HI
/
TC74HC4051AF 13,11,12, 13,11,12, /
Rotaly CH2 MID
VR CH2 LOW
1
MUX 10,8,14 10,8,14 6 CH2 FILTER
LEVEL/DEPTH
A/D
IC713
AD_MUX_2
TC74HC4051AF CHANNEL CH1 FADER
D MASTER OUT
JA702
/
1
MUX
15,17 15,17 /
2
FADER CH2 FADER
MUTE IC705
NJM4580MD
MASTER OUT
RCA PIN AMP/Filter
/2 /2
MIC IN
JA701 IC702(1/2) VR701 IC702(2/2) IC703
/
2 F CRFD ASSY
ADC_DATA CN1801
MIC IN NJM4565MD NJM4565MD AK4387ET ADC_BCK SSIRxD0
AMP MIC VOL
AMP MASTER DAC ADC_LRLK SSISCK0
PHONES JACK SSIWS0 9 9 3 3 / CROSS FADER
1
7,5 JH2002
MIXER SECTION CN1001 CN101 7,5 DECK2 SECTION

Rotaly
HP MIX VR /
2
3,5 37,35
HP VOL
DECK1 SECTION
TEMPO1_0 (MT) TEMPO2_0 (MT)

TEMPO1_1 (CT) TEMPO SLIDER / 2,4 38,36 / TEMPO SLIDER
TEMPO2_1 (CT)
2 1
CN102 CN2002
PC1202 PC2402
JOG_DIAL1_0 JOG_DIAL2_0
RPI-579N1 / 12 28 TCLKA TCLKC / 6 6 RPI-579N1
E PHOTO INTERRUPTER 1 1 PHOTO INTERRUPTER
PC1201 IRQ IRQ

JOG_DIAL2_1 PC2401
RPI-579N1 JOG_DIAL1_1
PHOTO INTERRUPTER / 14 26 TCLKB TCLKD / 8 8 RPI-579N1
1 1 PHOTO INTERRUPTER
JOG_1
IRQ IRQ
JOG_2
IC1201 IC1201
DYW**** JOG_TCH1 JOG_TCH2 DYW****

JOG JOG
Touch (PIC10F206-I/P) /
1
8 32 IRQ GPIO / 2 2 (PIC10F206- I/P) Touch
Touch uCom 1 Touch uCom
KEY/LED MATRIX IN/OUT
GPIO GPIO GPIO GPIO GPIO
LED_1/2 / 2 / 8 / 6 / 5 LED_3/4/5/6/7
18,20,26, 18,20,26,
/ 4
34,32 6,8 24,22 24,22
LED Tr.Buf. Tr.Buf. LED
35,33,31, 5,7,9, GRID_0/1/2/3/4/5/6/7/
27,25,23, 27,25,23,
29,30,28, 11,10,12, 21,17,15, 21,17,15,
26,24 14,16 13,11 13,11
3,5,7, 3,5,7,
F KEY 16,18, 24,22, Tr.Buf.
KEY_0/1/2/3 KEY_4/5/6/7/8
Tr.Buf. 10,12 10,12 KEY
20,22 20,18 KEY_9
14 14 Tr.Buf.
C DCK1 ASSY D PNL2 ASSY

10 DDJ-400
1 2 3 4
4.3 POWER BLOCK DIAGRAM
A MAIN ASSY
5
5
4 5 5 21 33 71 78 102 70
114 130
76
45
PC
CN1001
C
USB
CABLE JA101
1 10 17 29 40 57 66 98
110 120 126 141 152 162 170 1
DCK1 ASSY
V+VBUS
P101 1 5 75
86 88
CN101
39 10
5V / 500mA
16
6
6
PWR_ON2 30
PWR_ON
39
1 5
2 5
VOLTAGE DETECTION CIRCUIT

FAUT_DET
1
E
DDJ-400
V+3R3_D OVER
V+7
V-6
UNDER
UNDER 8 14 BRWS ASSY
V+5_A UNDER/OVER
V+5_HP UNDER/OVER JH2002 CN1801
4 4 CROSS FADER
CN103
6
1
V+7
1 7
20
21
20
21
CN2001
F
-
1
V 6
5 6 CN102
4 4
CRFD ASSY
14 D
PNL2 ASSY
7
30 30
7
31 31
14 CN2002
1 5 8
SBD
D210
HP_MUTE_DD
A_MUTE_DD
8
B HPJK ASSY
4
8
8
11
A
1 2 3 4
5. DIAGNOSIS
5.1 STARTUP SEQUENCE
A SH PIC (Left&Right) DAC (Master) DAC (HeadPhone) Opening Animation
Time Elapsed
State
Power ON Reset State Reset State Reset State
F/W action
(Connect USB cable with computer)
Communication 0ms
Other factor
HARDWARE SETUP
Initialize Ucom Registers
RAM CLEAR
Clear All RAM
LOAD PROGRAM
Load Initial Program

( Copy from ROM to RAM )
B
Load User Setting
Load Main Program

180ms
INITIALIZE
Initialize Parameters
Create and Start Tasks
Wait 600ms for Stable
C
Turn PWR_ON ON
950ms
Turn HP_MUTE ON
Turn PWR_ON2 ON
PIC Ucom
Identify the PIC Ucom

Emit Identifying
MIN(typical) 30ms - Data
MAX 1000ms
D
Wait for 55ms
Turn HP_AMP_MUTE OFF
Start FAULT_DET Detecting

1140ms
Fix the Boot Mode
E Initialize Peripheral Modules Start
Start MCLK
Continued on next page
12 DDJ-400
1 2 3 4
5 6 7 8
SH PIC (Left&Right) DAC (Master) DAC (HeadPhone) A

Opening Animation
Time Elapsed
State
F/W action
Communication From the previous page
Other factor
DAC Initialize
Turn DAC Reset OFF B
Turn DAC Reset ON
Turn DAC Reset OFF

C
Set DAC Proper

Parameters
1500ms
Wait 3000ms for

Guarding Noise
Turn A_MUTE OFF
Turn HPAMP_MUTE ON
D
Check if this board is

DDJ-400’s one or not End
4500ms
Stable State of Normal Boot Mode
SH DSP DAC ADC
DDJ-400 13
5 6 7 8
1 2 3 4
5.2 TROUBLESHOOTING
In this section, causes of failure, diagnostics points, and corrective measures can be searched for according to symptoms.
If there is an error indication, see to "5.6 ERROR INDICATION" before disassembly this unit and check the abnormal contents.
A For the relationship of each power-supply and signal system, see “4.3 POWER BLOCK DIAGRAM.”
If software of the product is updated before performing diagnostics, check that software updating has been performed properly
before proceeding to diagnostics.
If software updating has not been performed properly, update the software, following the instructions in
“8.2 UPDATING OF THE FIRMWARE.”
Contents
[0] Prior Confirmation [4] USB connection
[1] Failure in Startup (Failure in power-on) [5] AUDIO OUT
[2] Display [6] AUDIO IN
[3] Operations
B Waveform numbers and voltage confirmation-point numbers described in this section correspond to the numbers on the circuit
diagrams and PCB diagrams.
Be sure to check the failure points, as well as check for failure in their peripheral circuits.
[0] Prior Confirmation

[0-1] Checking in Service Mode
No. Cause / Symptom Diagnostics Point Item to be Checked Faulty Part Isolation / Corrective Action Reference
1 - Service mode Identify a failure point. After a failure point is identified, see the section 6.1 SERVICE MODE
referenced in this manual
[0-2] Checking Internal Cables

C No. Cause / Symptom Diagnostics Point Item to be Checked Faulty Part Isolation / Corrective Action Reference
1 Disconnection, Cables Check that all the cables are securely Securely connect a cable if it is not connected. 4.1 OVERALL
breakage, connected. If a cable is broken, replace it. WIRING DIAGRAM
or loose Check that there is no breakage in the Note: If an FFC cable is disconnected, be careful of
connection of cables. the orientation of the contacts when reconnecting it,
internal cables referring to the printed guide on the board.
[1] Failure in Startup (Failure in power-on)

[1-1] Failure in the power system
In a case where the unit is not started after the USB cable is connected and the unit is turned ON (all LED are not light)
1 Failure in the MAIN ASSY Check that the voltage of the direct pin If the voltage is outside the range of 4.75–5.25 V, 4.3 POWER BLOCK
D power system of USB jack (JA101) is in the range of failure in the USB-bus power, USB cable and DIAGRAM
(1) 4.75–5.25 V. USB jack (JA101). 5.3 MONITORING
OF POWER SUPPLY
AND VOLTAGE
2 Failure in USB- MAIN ASSY Check that the V+VBUS voltage is If the voltage is 0 V, the wire for the IC protector 4.3 POWER BLOCK
bus power lower than that of the direct pin of (P101) may be broken. DIAGRAM
USB jack (JA101) by approximately 0.1
to 0.2 V.
3 Power failure in MAIN ASSY Check that the V+3R3_SH voltage is If the normal voltage of V+3R3_SH is not restored, 4.3 POWER BLOCK
the UCOM higher than 3.0 V. IC202 or a part that is connected to V+3R3_SH on DIAGRAM
the MAIN ASSY may be defective, or connection
may be poor.
4 Power failure in MAIN ASSY If the V+3R3_SH voltage is higher If the PWR_ON signal is "L," V+5D, V+5_LED will 4.3 POWER BLOCK
the UCOM than 3.0 V, check that Q203 (5V FET not be output, because Q203 is not turned ON. DIAGRAM
E SW) is functioning properly. The error-detection circuit may have been activated. 10.11 VOLTAGES /
Go to [5]. WAVEFORMS
If the PWR_ON signal is "H," the error-detection
circuit is not activated. Check the voltages of all
power ICs. If they are normal, see "[1-2] Failure in
the microcomputer system."
5 Power failure in MAIN ASSY Check if the error-detection circuit has If the FAULT_DET signal is "L," the error-detection 4.3 POWER BLOCK
the UCOM been activated. circuit has been activated. Go to [6]. DIAGRAM
If the FAULT_DET signal is "H," the error-detection
circuit is not activated. Check the voltages of all
power ICs. If they are normal, see "[1-2] Failure in
the microcomputer system."
6 Failure in the MAIN ASSY Deactiveate the voltage monitoring The voltage monitoring circuit can be deactivated 4.3 POWER BLOCK
power system circuit then check the section with by removing R267 (0 :) on the FAULT_DET. DIAGRAM
F (2) improper voltage. See the notes in “5.3 MONITORING OF POWER 5.3 MONITORING
Identification of SUPPLY AND VOLTAGE” before proceeding to OF POWER SUPPLY
defective power further diagnostics. AND VOLTAGE
system To identify the section with improper voltage, check 10.11 VOLTAGES /
the voltage at each point on the MAIN ASSY. WAVEFORMS
14 DDJ-400
1 2 3 4
5 6 7 8
[1-2] Failure in the microcomputer system

1 Power failure in MAIN ASSY Check the power terminal of the Check the power and voltage are normal. 4.3 POWER BLOCK
the UCOM UCOM (IC406). Check the power line and the parts, such as coils DIAGRAM A
(beads), resistors, and capacitors. 10.11 VOLTAGES /
If no problem was found with the parts, power line, WAVEFORMS
and conduction between the power supply and
GND, the UCOM (IC406) may be defective.
2 UCOM MAIN ASSY Check the Reset terminal (pin 46) of In normal operation the voltage of the Reset 10.11 VOLTAGES /
Reset circuit the UCOM (IC406). terminal (Pin 46) is high. If it is low, check if the WAVEFORMS
error voltage at V+3R3_SHD is 2.7 V or less. Check the
reset line, resistors, capacitors, and the Reset IC
(IC409).
3 UCOM MAIN ASSY Check the oscillation waveforms of the If the oscillation waveforms are abnormal, check the 10.11 VOLTAGES /
X'tal error X'tal (X404). resistor on the oscillation-signal line, the capacitor, WAVEFORMS
and X'tal (X404). If nothing is wrong with these
parts, the UCOM (IC406) may be defective.
4 UCOM MAIN ASSY After startup, check the lighting Perform the re-update o the firmware 5.6 ERROR B
startup error statuses of the LEDs. (8.2 UPDATING OF THE FIRMWARE). INDICATION
(For example, although some of the If the normal status is not recovered after all above 8.2 UPDATING OF
LEDs light and blink, the unit is not steps are performed, the UCOM (IC406), FLASH THE FIRMWARE
started up properly.) ROM (IC408) or FLASH ROM peripheral parts may
be defective.
[2] Display
[2-1] Any one of the LEDs does not light

1 Defective LED, Periphery of the Check the difference in electrical If the difference is outside the normal range, the -
C
Defective LED abnormal LED potentials between the positive signal lines at the periphery of the corresponding
signal line and negative electrodes of the LED LED, resistors, or the LED itself may be defective.
(normally, it must be approx. 2.2 V ).
[2-2] Several LEDs do not light or abnormal light

1 Defective MAIN ASSY Check the control signal (GRID*, If the control signal is abnormal, the UCOM (IC406), 10.11 VOLTAGES /
LED signal LED*) of the target LED. GRID signal line and LED signal line may be WAVEFORMS
line,Defective defective. TV[WKH
UCOM
2 Defective DCK1 ASSY Check the transistors for LED drive. If the signal waveform is abnormal, the transistor 10.11 VOLTAGES /
transistor for PNL2 ASSY may be defective. WAVEFORMS
LED drive ? D
3 Defective LED Periphery of the Check the connections of the LED If the signal waveform is abnormal, the LED may be -
abnormal LED and the forward voltage defective.
(approx. 3.2 V: blue, 2.2 V: others)
between both ends of the LED.
DDJ-400 15
5 6 7 8
1 2 3 4
[3] Operations
Operation of other than MIC LEVEL volume operating elements can be confirmed in Service Mode.
A
If the MIC LEVEL volume do not function, see “[6] AUDIO IN”.
[3-1] Tact switch do not function.

1 Loose DCK1 ASSY Check the control signal (GRID*, When the matrix key is pressed : 10.11 VOLTAGES /
connection / PNL2 ASSY LED*) of the target tact switch.. Normally, repeat High/Low in grid cycle when a tact WAVEFORMS
defective parts Periphery of the switch is ON, and High (approx. 3.3 V) when it is TV[WKQ
abnormal button OFF. If it is not, tact switch is defective, signal line,
FFC, or connector may be in failure.
When the direct key is pressed :
Normally, Low(approx 0 V) when a tact switch is
ON, and High (approx 3.3 V) when it is OFF.
If it is not, the tact switch is defective, signal line,
FCC, or connector may be in failure.
B
2 Defective MAIN ASSY If the symptom persists after the The UCOM (IC406) may be defective. -
UCOM (IC406) above corrections.
[3-2] Rotary selector not controllable

1 Loose BRWS ASSY Check that BROWSE rotation If the signals are not normal, signal line, FFC, 10.11 VOLTAGES /
connection / PNL2 ASSY detection signal jumper wire, connector, resistor, the rotary selector WAVEFORMS
defective parts MAIN ASSY (BROWSE_ENC_0/1). may be defective. R"
C
[3-3] Rotary volumes / Slide volumes / Faders not controllable
1 Loose DCK1 ASSY Check the AD signal (AD_*) of the If the voltage of the signal line does not change 10.11 VOLTAGES /
connection / PNL2 ASSY target VRs, sliders or faders. between 3.3 V and 0 V when the VRs, sliders, or WAVEFORMS
defective parts CRFD ASSY For the signal connected to the faders are operated, the corresponding operating YGIJLMN
MAIN ASSY multiplexer (IC711, IC712, IC713), also element, signal line, multiplexer (IC711, IC712,
check the AD signal (AD_MUX_*) IC713), FFC, jumper wire, connector, resistor,
after switching. or capacitor may be defective.
If the voltage of the AD_TEMPO 1_1/2_1 signal line
is not 1.65 V, or if the voltage of the AD_TEMPO
1_0/2_0 signal line does not change between 3.3
V and 0 V when the tempo slider is moved, the
tempo slider, signal line, multiplexer (IC711, IC712,
D
IC713), FFC, jumper wire, connector, resistor
or capacitor may be defective.
[3-4] Abnormalities regarding the Jog dial

After the Jog dial Assy is disassembled then reassembled, be sure to check that the load value for the Jog dial is within the
specified range. Refer to the "6.1 SERVICE MODE_-2: Measurement mode of the load of JOG dial".
[3-4-1] Turning of the Jog dial is not detected

E
1 Loose DCK1 ASSY Check the Jog dial rotation detection If either waveform is abnormal, connection of signal 10.11 VOLTAGES /
connection / PNL2 ASSY signal (JOG_DIAL1_0/1_1 and line, resistor, capacitor and the photo interrupters WAVEFORMS
defective parts JOG_DIAL2_0/2_1). (PC1201, PC1202, PC2401 and PC2402) may be =UF
defective.
2 Defective photo DCK1 ASSY Check the phases of the Jog dial If the waveforms are normal but the phases are not 10.11 VOLTAGES /
interrupter PNL2 ASSY rotation detection signal waveforms correct, the photointerrupters (PC1201, PC1202, WAVEFORMS
(JOG_DIAL1_0/1_1 and JOG_ PC2401 and PC2402) may be mounted improperly. =UF
DIAL2_0/2_1)
Are identical to those described in
"-3: Photo Interrupter check mode"
in "6.1 SERVICE MODE" when the
Jog dial is turned.
F
16 DDJ-400
1 2 3 4
5 6 7 8
[3-4-2] Touching of the Jog dial is not detected, or touching is detected although the Jog dial is not touched.
1 Loose DCK1 ASSY Check the signal level of Pin 4 of The signal is "H" while the Jog dial is not touched 10.11 VOLTAGES /
connection / PNL2 ASSY IC1201/IC2401. and becomes "L" when it is touched. WAVEFORMS A
defective parts If it is abnormal, go to [2]. C
If it is normal, go to [5].
2 Loose DCK1 ASSY Check the signal level of Pin 3 of The signal produces a pulse waveform in the 10.11 VOLTAGES /
connection / PNL2 ASSY IC1201/IC2401. frequency range of 900 to 1300 kHz while the Jog WAVEFORMS
defective parts dial is not touched and a pulse waveform in the
frequency range of 400 to 700 kHz while it is
touched.
If it is normal, IC1201/IC2401 may be defective.
If the signal produces a pulse waveform in the
frequency range of 900 to 1300 kHz regardless of
the jog dial's being touched or not, go to [3].
For other abnormal, go to [4].
3 Loose DCK1 ASSY Check the connection between Jog Possible causes are poor connection between the -
connection / PNL2 ASSY dial top face plate (DAH3209) and aluminum plate of the Jog dial and the KN1201/ B
defective parts IC1201/IC2401. KN2401 metal fittings for grounding, or poor
As the surface of the Plate is coated, a connection or a defective part in the circuits
conduction check must be performed between the KN1201/KN2401 and IC1201/IC2401.
on the plate side surface facing the
Jog dial (DNK6763) through their gap.
4 Loose DCK1 ASSY Check the connection between Poor connection or a defective part in the circuits -
connection / PNL2 ASSY KN1201/KN2401 and IC1201/IC2401. between the KN1201/KN2401 and IC1201/IC2401.
defective parts
5 Loose DCK1 ASSY Check the connection between If the connection is properly made, the UCOM -
connection / PNL2 ASSY IC1201/IC2401 and UCOM (IC406). (IC406) may be defective.
defective parts
[3-4-3] Jog dial turns too freely. (The load value for the Jog dial is outside the specified range.) C
1 Improper Jog dial ASSY Check the load value for the Jog dial is If the load value is outside the specified range, 6.1 SERVICE MODE
assembly of the within the specified range, referring to detach the Jog dial then reapply grease. 7. DISASSEMBLY
Jog dial “Advanced Setting” in “6.1 SERVICE See "Procedure for applying grease during
MODE_-2: Measurement mode of reassembly of the Jog Dial" in "7. DISASSEMBLY."
the load of JOG dial.”
[3-4-4] Resistance to turning the Jog dial is too strong. (The load value for the Jog dial is outside the specified range.)
1 Improper Jog dial ASSY Check the load value for the Jog dialis If the load value is outside the specified range, 6.1 SERVICE MODE
assembly of the within the specified range, referring to perform manual running-in rotations of the Jog dial. 7. DISASSEMBLY
Jog dial “Advanced Setting” in “6.1 SERVICE See "Procedure for applying grease during reas- D
MODE_-2: Measurement mode of sembly of the Jog Dial" in "7. DISASSEMBLY."
the load of JOG dial.”
[4] USB connection

[4-1] Unit cannot be recognized by the PC when connected to the PC via USB connection.
0 Wrong setting of Setting of the Check the setting of the application The PC will not recognize the unit if the setting of Operating
the application application installed installed on the PC is appropriate. the application installed on the PC is inappropriate. Instructions
installed on the on the PC
PC
1 Failure in MAIN ASSY Check the lighting statuses of the If no LED lights, see [1] Failure in Startup. [1] Failure in Startup E
startup LEDs during startup. (14 page)
2 Defective MAIN ASSY Check the communication waveforms If the unit is connected to a PC via the USB cable, 10.11 VOLTAGES /
UCOM (IC406) of the USB_DP/DN lines. communication will be performed through the USB WAVEFORMS
DP/DN lines. If communication cannot be
performed, check the USB cable, connectors, [1-2] Failure in the
internal cables, resistors, capacitors, and filters. microcomputer
If nothing is wrong with them, UCOM (IC406) is system
defective. Check the items listed in “[1-2] Failure in (15 page)
the microcomputer system”.
DDJ-400 17
5 6 7 8
1 2 3 4
[5] AUDIO OUT
[5-1] MASTER OUT is not output.

A
0 Wrong setting of Setting of the Check the output setting of the The signal will not output if the output setting of the Operating
the application application installed application installed on the PC is application installed on the PC is inappropriate. Instructions
installed on the on the PC appropriate.
PC
1 - MAIN ASSY Check the audio signal is output from If MASTER connector outputs, go to [3]. 10.11 VOLTAGES /
DAC (IC703 pin 10, 11) for MASTER If MASTER connector does not output, go to [2]. WAVEFORMS
OUT.
2 Loose MAIN ASSY Check the digital input signals to DAC
If any of those signals is abnormal, connection 10.11 VOLTAGES /
connection / (IC703: Pin1-5) for MASTER OUT. of the corresponding signal line may be loose, WAVEFORMS
defective parts resistor, capacitor, UCOM (IC406) may be
defective.
If all signals are normal, the DAC (IC703) and its
peripheral circuitry do not function properly.
B -
3 Mute signal MAIN ASSY Check the level of the A_MUTE_DD Normally, A_MUTE_DD signal must be Low
loose audio muting signal. (Approx. -6 V, muting canceled). When it is High
connection / (Approx. 3.3 V), muting is activated and no sound
defective parts is output. The A_MUTE_DD signal becomes High,
possibly because connection of the corresponding
signal line is loose, muting circuit (Q707, Q708) or
muting drive circuit (Q709, Q710 Q711, Q713 etc.) is
defective.
4 Mute signal MAIN ASSY Check the level of the A_MUTE audio Normally, A_MUTE signal must be Low (Approx. -
loose muting signal. 0 V, muting canceled). When it is High (Approx.
connection / 3.3 V), muting is activated and no sound is output.
defective parts The MUTE signal becomes High, possibly because
connection of the corresponding signal line is loose,
transistor (Q709) or UCOM (IC406) is defective.
C 5 MASTER OUT MAIN ASSY Identify the point where the audio If the audio signal abnormal, connection of the 10.11 VOLTAGES /
line loose signal is interrupted on the line corresponding signal line my be loose , resistor, WAVEFORMS
connection/ from pins 10 and 11 of IC703 (DAC capacitor, transistor, OP amp (IC705) or jack for @
defective parts for MASTER OUT) to the jack for MASTER OUT may be defective.
MASTER OUT (JA702).
[5-2] HEAD PHONE signal is not output.

Check first MASTER OUT is normal. If the MASTER OUT is abnormal, see [5-1] MASTER OUT is not output.
0 Wrong setting of Setting of the Check the output setting of the The signal will not output if the output setting of the Operating
the application application installed application installed on the PC is application installed on the PC is inappropriate. Instructions
installed on the on the PC appropriate.
PC
D 10.11 VOLTAGES /
1 Loose MAIN ASSY Check the audio signal (HP_AMP_L/ If no audio signal is output, the MAIN ASSY may be
connection / R), using pins 5 and 7 of the JH101 on defective. Go to [2]. WAVEFORMS
defective parts the MAIN ASSY. If an audio signal is output, connection between the >S
HPJK and MAIN ASSYs may be loose, connections
inside the HPJK ASSY may be loose, or these
ASSYs may be defective. Go to [6]. 5.4 ABOUT FUNCTION
If an audio signal is small, it way be in “ Function LIMIT MODE AT
limit mode at low voltage mode ”. LOW VOLTAGE
See “5.4 ABOUT FUNCTION LIMIT MODE AT LOW
VOLTAGE”
2 - MAIN ASSY Check the audio output signal, using If an audio signal is output, go to [4]. -
pins 10 and 11 of the HP DAC (IC701). If an audio signal is not output, go to [3].
3 Loose MAIN ASSY Check the audio input signal, using If any of those signals is abnormal, connection 10.11 VOLTAGES /
connection / pins 1 - 5 of the HP AMP (IC701). of the corresponding signal line may be loose or WAVEFORMS
E defective parts resistor, capacitor or UCOM (IC406) may be
defective. Note: measurement
If all signals are normal, the DAC (IC701) and its point is different
peripheral circuitry do not function properly.
4 Loose MAIN ASSY Check the audio input signal, using If the input signal is abnormal, connection of the -
connection / pins 3 and 5 of the HP AMP (IC706). audio input signal line may be loose, resistor or
defective parts capacitor may be defective.
If the input signal is normal go to [5].
5 Mute signal MAIN ASSY Check the level of the muting signal Normally, muting signal must be High (Approx. 3.3 -
loose (IC706 pin 2) for HP AMP. V, muting canceled). When it is Low (Approx. 0 V),
connection / muting is activated and no sound is output. The
defective parts signal line may be defective.
If the muting signal is High and normal, the HP AMP
or mute circuit (Q705, Q706) may be defective.
F
6 Loose HPJK ASSY Identify the point where the audio If the audio signals is abnormal, connection of the -
connection / signal is interrupted on the line from corresponding signal line may be loose, resistor,
defective parts JH101 to the jack for HP output capacitor, jack for HP output or mute circuit
(JA1601). (Q1601, Q1602) may be defective.
18 DDJ-400
1 2 3 4
5 6 7 8
[6] AUDIO IN
[6-1] MIC INPUT signal is not output

A
Check first MASTER OUT is normal. If the MASTER OUT is abnormal, see [5-1] MASTER OUT is not output.
1 Loose MAIN ASSY Check the audio signal (MIC_IN), If no signal is output, the MIC jack or MIC cable -
connection / using pin2 of the MIC input jack may be defective. If an signal is output, connection
defective parts (JA701). of the corresponding signal line may be loose,
resistor, capacitor, OP amp, MIC volume ADC
(IC708) may be defective.
2 Loose MAIN ASSY Check the audio signal, using pin1 of If no signal is output, connection of the -
connection / the ADC (IC708) for MIC. corresponding signal line may be loose or the
defective parts resistor, capacitor, OP amp, MIC volume, jack
terminal may be defective.If an signal is output, the
ADC (IC708) and its peripheral circuitry may be
defective.
B
3 Loose MAIN ASSY Check the digital input/output signals If any of those signals is abnormal, connection 10.11 VOLTAGES /
connection / of the ADC (IC708: pins 9 - 13) for of the corresponding signal line may be loose or WAVEFORMS
defective parts MIC. the resistor, capacitor, UCOM (IC406) may be
defective. If all signals are normal, the ADC (IC708) Note: measurement
and its peripheral circuitry do not function properly. point is different
DDJ-400 19
5 6 7 8
1 2 3 4
5.3 MONITORING OF POWER SUPPLY AND VOLTAGE

MAIN uCOM (IC406) of this unit always monitors for power and voltage failure of the unit and will shut the unit off
immediately after an error is detected.
A
• Content to be monitored
Power supply voltage drop and power supply voltage rise generated by short-circuiting between any power-supply IC and
GND or excess current inside the MAIN ASSY
Power to be monitored: V+5_A, V+5_HP, V+7, V-6, V+3R3_D
• MAIN UCOM detection terminal and its terminal voltage
TP terminal near the R267 of MAIN ASSY or IC406 (MAIN UCOM) pin 107 FAULT_DET.
Normal: Approximately 3.3 V
Abnormal: 0 V
• Timing of monitoring start
After the unit is turned ON : After 1000 ms
B
• Timing upon judgment as a failure
After an error is detected : After 50 ms
• LED indication when an error is generated
All LEDs are unlit.
• Restoration method
If the unit shuts itself down because an error is detected, disconnect the USB cable after perform diagnosis,
wait for a while and then connect the USB cable on again.
• Diagnostic procedure
Disconnect the USB cable.
Check with the tester whether the monitoring voltage is short-circuited to the GND.
C
If it is short-circuited, repair the abnormal part and check it becomes normal voltage.
Remove R267 from the MAIN ASSY. Note: This step will disable power monitoring.
Reconnect the USB cable.
As the unit is turned on in a normal way, check each voltage in this state.
Note: Because power will be forcibly supplied even if any voltage is abnormal, if abnormal voltage continues,
defective point may produce heat, which may be dangerous. Therefore, during diagnosis, be sure to disconnect
the USB cable several seconds after they are connected so that forcible powering will not continue.
If voltage of any power IC is abnormal, circuit that uses that power or power IC itself may be defective.
Repair the defective part then check that the power and voltage of the repaired part becomes normal.
Return R267 to its original position on the MAIN ASSY.
Note: This step will enable power monitoring.
D
Circuit of this unit monitors for power and voltage failure from USB bus power and will shut the unit off immediately
after an error is detected.
Power supply voltage failure from the USB bus power
Power to be monitored: V+VBUS
• MAIN UCOM detection terminal and its terminal voltage

TP terminal of V_DET signal of MAIN ASSY or IC406 (MAIN UCOM) pin 108 V_DET.
Normal: HI (3.3 V)
Abnormal (V+VBUS 4.2 V or less ) : LOW (0 V)
E • Timing of monitoring start

After an error is detected : Within 1 ms
• LED indication when an error is generated
All LEDs are unlit.
• Restoration method
If the unit shuts itself down because an error is detected, disconnect the USB cable after perform diagnosis,
wait for a while and then connect the USB cable on again.
F
• Diagnostic procedure
Connect the USB cable and then check the V+VBUS power.
If voltage is abnormal, circuit that uses that power or power IC itself may be defective.
20 DDJ-400
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5.4 ABOUT FUNCTION LIMIT MODE AT LOW VOLTAGE

This product always monitors voltage drop of the VBUS power (power to be supplied via a USB cable), which may be caused
by connection of a peripheral device that is not covered under warranty or an erroneous operation. If an abnormality is A
detected, product will limit the maximum output level of the headphone so that it can operate in a lower
power-consumption mode.
If an abnormality is generated, check the connected headphones and computer.
Drop in power voltage in the MAIN ASSY to be supplied via a USB cable
(Function limit mode at low voltage transition condition V+VBUS : 4.2 V to 4.5 V)
* Refer to “5.3 MONITORING OF POWER SUPPLY AND VOLTAGE” when 4.2 V or less.
Power voltages to be monitored : V+VBUS
• Microcomputer Detection terminal and its terminal voltage

TP terminal for service of MAIN ASSY [V_DET_AD]. B
Normal : Approximately 2.3 V to 2.6 V
Abnormal : < 2.3 V
• Timing of monitoring start


After an error is detected : After 50 ms
• Headphone level when an error is generated

Maximum output level of the headphone is suppressed to approximately 15%.
If normal power voltage is recovered, suppressed maximum output level of the headphone will return to its original level. C
• PAD LED of when an error occurs

Both Pad6 LEDs on the left and right deck blink.
When power voltage returns to normal condition, blink is cancelled.
• Items to be checked
Check if headphones with impedance outside the range of the guaranteed specifications (impedance 32 ohms or less)
are connected.
Check if a monaural plug is connected to the headphones connector.
Connected computer may not be able to supply enough USB power (may not meet USB standards).
DDJ-400 21
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5.5 OPERATION CHECK WITH rekordbox

[Install rekordbox]
A Below is a brief description of how to install rekordbox on PC / Mac. For details, refer to the operating instructions.
Please note that it is not necessary to install driver software for DDJ-400. (It operates with OS standard built-in driver) PC / Mac
environment etc. for installing rekordbox etc. are as follows.
Minimum operating environment
B • To obtain the latest operating and environment, compatibility, and the latest OS system, please refer to "Operating
environment" of "rekordbox.com".
https://rekordbox.com
• Please use latest version and service pack of OS.
Please download rekordbox software by accessing "rekordbox.com".

To download it, you need to register the user account of "rekordbox".
Unzip the downloaded file and double-click on the decompressed file to launch the installer.
Please read the contents of license agreement carefully. If you agree, select [Agree] and then click [Next] (in case of macOS
and OS X [Continue] ) to start the installation.
When the installation is completed, an installation completion message is displayed.
Click [Finish] to complete the rekordbox installer (in case of macOS and OS X,click [Close]).
C
• Please use the latest version of rekordbox. If the version is old, it may not support this product.
• In order to use rekordbox's [PERFORMANCE] mode (mode where DJ performance function can be used), activation by
license key is required separately.
[Operating procedure]
Connect the headphones to the [PHONES] jack.
Connect the device such as a powered speaker, power amplifier, component stereo, etc. to the [MASTER] terminal.
Turn on the PC / Mac.
Connect this product to the PC / Mac via a supplied USB cable.
(When connecting to USB Type-C terminal, USB Type-C (male) - USB A (female) cable is required separately)
Turn on the devices connected to the [MASTER] terminal (powered speaker, power amplifier, component stereo, etc.).
D
[Connection method]

USB
Cable (supplied) PC/Mac
E Amplifier built-in
speaker etc.
F
Headphone
22 DDJ-400
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[Starting rekordbox] Adding audio tracks into [Collection]

It is necessary to register an account for using rekordbox. The [Collection] screen contains a list of audio track files
It is necessary to activate rekordbox dj using the supplied managed by rekordbox. A
license key. Register audio tracks on your PC/Mac to rekordbox, and
For details about each procedure, click [Manual] under analyze them so they can be used on rekordbox.
[Support] of the following site, and then refer to “rekordbox
Introduction.” 1 Click [Collection] on the tree view.
https://rekordbox.com A list of tracks which are registered in [Collection] is
displayed.
For mac OS/OS X
In Finder, open [Applications] folder, and then double-click 2 Open Finder or Windows Explorer, and then drag
[rekordbox] icon. & drop audio track files or folders with audio track
files into the track list.
For Windows 10 Audio track files are added into [Collection], and then
In [Start] menu, click [rekordbox] icon under [Pioneer]. analyzing of waveform information for audio track files
starts. Wait until analyzing of all audio track files is B
For Windows 8.1 completed.
In [Apps view], click [rekordbox] icon.
For Windows 7 [Loading an audio track into a deck]

In the Windows [Start] menu, click [rekordbox] icon under
[All Programs] > [Pioneer] > [rekordbox X.X.X]. This section explains how to load a track into Deck 1 (left)
as an example.
Turn the rotary selector to select a track from

[Collection], and then press the [LOAD] button on Deck
[Checking audio setup] 1 (left).
The selected track is loaded. C

Check that [Audio] settings of [Preferences] on rekordbox
are set as followings.
For mac OS/OS X

[Audio]: [DDJ-400]
[Output channels]:
[Master Output]: [DDJ-400 : MASTER + audio device
name on Mac]
[Headphones Output]: [DDJ-400 : PHONES]
* When [PC MASTER OUT] is off, [Master Output] in the

[Audio] setting is [DDJ-400 : MASTER].
D
For Windows
[Audio]: [DDJ-400 WASAPI]
[Output channels]:
[Master Output]: [DDJ-400 WASAPI : MASTER +
audio device name on PC]
[Headphones Output]: [DDJ-400 WASAPI :
PHONES]
* When [PC MASTER OUT] is off, [Master Output] in the

[Audio] setting is [DDJ-400 WASAPI : MASTER].
* PC MASTER OUT is a function to output the master

sound of rekordbox dj from the speaker of PC/Mac. By the E
default, PC MASTER OUT is set to on.
DDJ-400 23
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[Playing a track] 5 Turn the [MASTER LEVEL] knob to adjust the audio
level of the speakers.
This section explains how to output sound from Deck 1 (left) Adjust the audio level output from the [MASTER] output
A as an example. terminals to an appropriate level.
1 Set the positions of the knobs, etc., as shown below.

Names of knobs, etc. Position
TRIM knob Turned fully counterclockwise
EQ (HI/MID /LOW) knobs Center position
FILTER knob Center position
Channel fader Bottom position
MASTER LEVEL knob Turned fully counterclockwise
Crossfader Center position
B 2 Press the [PLAY/PAUSE ] button to play the track.
* To adjust the volume for speakers of PC/Mac, operate

speakers of PC/Mac instead of using the [MASTER
LEVEL] knob.
[Monitoring the sound with headphones]
This section explains how to output sound from Deck 1 (left)

3 Turn the [TRIM] knob. as an example.
Adjust the [TRIM] knob so that the [CHANNEL LEVEL]
indicator’s orange indicator lights at the peak level. 1 Set the positions of the knobs as shown below.
Names of knobs, etc. Position
C
HEADPHONES MIXING knob Center positon
HEADPHONES LEVEL knob Turned fully counterclockwise
2 Press the Headphone [CUE] button of the channel 1.
3 Turn the [HEADPHONES LEVEL] knob.

Adjust the output level from the [PHONES] output terminal.
[Closing the system]
1 Close rekordbox.
4 Move the channel fader to the maximum level.
D
2 Disconnect the USB cable from the PC/Mac.
E
5.6 ERROR INDICATION
No. Abmormality LED / Indication Note
Power Supply All LED's right off This state is entered when an error is detected in the USB bus power
1 Abnormality supply status.
If abnormality is detected at startup, no opening display will be done.
MAIN UCOM All Level Meter's This happens when FLASH-ROM is not written correctly, such as when the
FLASH-ROM (Left CH / Right CH) update fails.
2
Abnormality is blinking Even in this case you can continue updating.
The same LED display will be done in the update mode.
24 DDJ-400
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6. SERVICE MODE
6.1 SERVICE MODE
Outline of Service Mode
A
There are two service mode for this unit.
Service Mode Service Mode

– 1 Version check mode – 1 Version check mode
– 2 Check mode of the buttons, knobs, etc – 2 Measurement mode of the load of JOG dial
– 3 Factory reset mode – 3 Photo interrupter check mode
– 4 Voltage value display mode
– 5 Voltage value fluctuation range check mode
– 6 Cross fader calibration mode
Startup Method in Service Mode B
How to enter Service Mode How to enter Service Mode

Connect the USB cable while pressing the Connect the USB cable while pressing the
[ MASTER CUE ] button and HP CUE [ 1 ] button. [ MASTER CUE ] button and HP CUE [ 2 ] button.
Method for Quittng the Service Mode

Please disconnect the USB cable connected to this unit.
D
Caution when the board is mix-mounted
When DDJ-400's firmware is written on DDJ-SB3's board by
mistake, 2 red LEDs of CH level meter blink.
DDJ-400 25
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A
How to Mode changing and Page changing
USB cable is not connected.
Service Mode Service Mode
Press the [MASTER CUE] button + HP CUE [1] button Press the [MASTER CUE] button + HP CUE [2] button
+ +
Connect a USB cable. Connect a USB cable.
Check the PIC microcomputer. *1 Check the PIC microcomputer. *1
Service Mode (Page 1) Service Mode (Page 1)

– 1 Version check mode – 1 Version check mode
B
Press the [SHIFT] button on the (Left) DECK. Press the [SHIFT] button on the (Right) DECK. Press the [SHIFT] button on the (Left) DECK. Press the [SHIFT] button on the (Right) DECK.

– 2 Check mode of the buttons, knobs, etc – 2 Measurement mode of the load of JOG dial
Press the [SHIFT] button on the (Left) DECK. Press the [SHIFT] button on the (Right) DECK. Press the [SHIFT] button on the (Left) DECK. Press the [SHIFT] button on the (Right) DECK.

– 3 Factory reset mode – 3 Photo interrupter check mode
Press the [SHIFT] button on the (Left) DECK. Press the [SHIFT] button on the (Right) DECK. Press the [SHIFT] button on the (Right) DECK.
Service Mode (Page 4)

– 4 Voltage value display mode
C
Press the [SHIFT] button on the (Left) DECK. Press the [SHIFT] button on the (Right) DECK. *1 : A caution will appear if the firmware of the built-in PIC microcomputer is
not for DDJ-400.
Service Mode (Page 5) The caution will appear right after the Service Mode or started.
– 5 Voltage value fluctuation range check mode All LEDs of the CH level meter will light on.
The caution will be cleared if you press and hold the ROTARY
Press the [SHIFT] button on the (Left) DECK. Press the [SHIFT] button on the (Right) DECK. SELECTOR button for more than 5 seconds.
Then you can move on to the Service Mode.
Service Mode (Page 6)
– 6 Cross fader calibration mode
Press the [SHIFT] button on the (Right) DECK.
Press the [SHIFT] button on the (Left) DECK to Press the [SHIFT] button on the (Right) DECK to
move to the previous page. move to the next page.
(This applies to Service Mode and .) (This applies to Service Mode and .)
E
-1 -2 -3 -4
-5 -6
When you press the [SHIFT] button to enter the new test page,
LED corresponding to each page will blink Red for a moment (for 1 to 2 seconds).
After the "Red-blinking" is over and the light is off, testing of each page will start.
F
26 DDJ-400
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Service Mode – 1 Version check mode

Mode outline A
This mode is to check the version of the firmware. Version is displayed using the deck LEDs.
Advanced Setting
Version
Ones place 1 2 3 4 5 6 7 8
x.xx First desimal place
Second desimal place

1
1
2
2
3
3
4
4
5
5
6
6
7
7
8
8
9
* When all horizontal LEDs are turned off, it means zero (0).
* 1st digit can express 1-8. C
Service Mode – 2 Check mode of the buttons, knobs, etc

Mode outline
This is to check the operation of all the buttons, knobs, etc. on the top surface.
*All buttons : Light on when button is pressed and light off when button is released.
Advanced Setting
When entered this mode, all LEDs light on.
By pushing ROTARY SELECTOR button, LEDs change "all light on -> all dimmer out -> all light off -> all light on …."
D
Operation of all the buttons, knobs, etc. can be done when LEDs are all light off.
TYPE A
TYPE C
TYPE B TYPE B
TYPE A TYPE A
TYPE D
TYPE C
TYPE C
E
TYPE B TYPE B
TYPE B TYPE B
TYPE C
AREA 1 AREA 2 AREA 3
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Element type UI part name Trigger LED to check

Push type SW (with LED) Press Its own LED
ROTARY SELECTOR Press All LEDs light on -> All
A dimmer out -> All light off
SHIFT(Left/Right) Nothing (Use to change the mode)
LOAD(Left/Right) Press CUE
CUE/LOOP CALL Press IN/-4BEAT
(Left/Right)
Push type SW (no LED) CUE/LOOP CALL Press OUT
(Left/Right)
BEAT Press HP CUE 1
BEAT Press HP CUE 2
FX SELECT Press MASTER CUE
JOG (TOUCH) Touch PLAY/PAUSE
(Left/Right)
B TYPE A JOG dials (rotation), Rotary selector Rotate TYPE A (* 1)
TEMPO sliders, Channel faders, TRIM knobs, Rotate(Slide) TYPE B (* 2)
TYPE B
HI/MID/LOW EQ knobs, FILTER knobs
MASTER LEVEL knob, Cross fader, Rotate(Slide) TYPE C (* 3)
HEADPHONES MIXING knob,
TYPE C
HEADPHONES LEVEL knob, FX LEVEL/
DEPTH knob
TYPE D Slide switch Slide TYPE D (* 4)
Caution : Except for TYPE A and TYPE D, the number of lighting LEDs will change based on the position of each knob/fader.
(i.e., when volume is minimum, all LEDs will light off; when volume is maximum, all LEDs will light on.)
TYPE A (* 1) TYPE B (* 2) TYPE C (* 3) TYPE D (* 4)

Rotation operation of the rotary Position of the knob/fader will be Position of the knob/fader will be Operation of the Slide switch will be
C encoder will be displayed using the displayed using the following 5 LEDs displayed using the following LEDs displayed using 3 LEDs of right Pad
following 8 LEDs. according to the move. according to the move. mode buttons.
LEDs will light on according to the LEDs will light on according to the
position of the knob/fader right after position of the knob/fader right after
each knob/fader is moved. each knob/fader is moved.
* CROSSFADER: All LEDs will light off
when it is in far left; All LEDs will light
on when it is in far right.
For preventing from forgetting check.

When in all light off mode, controller monitors the operation records of each controls in 3 areas.
If you have checked all controls, FX ON/OFF is blinked for a few seconds.
When you move to next or previous page without check completion, following LEDs are blinked for a few seconds.
• When check in area 1 is not completed, left 8 Pads are blinked for a few seconds.
• When check in area 2 is not completed, CH 1 HP CUE and CH 2 HP CUE are blinked for a few seconds.
• When check in area 3 is not completed, right 8 Pads are blinked for a few seconds.
Judgement condition of operation completion

• Buttons : You press the button once at least.
• Faders : You slide the fader to right edge and left edge once at least.*1
E Or you slide the fader to top edge and bottom edge once at least.*1
• Knobs : You turn the knob fully clockwise and fully counterclockwise once at least.*1
• JOG touch : You touch the top surface once at least.
• JOG rotation : You rotate it clockwise one turn.*2
• Rotary selector : You rotate it clockwise 24 clicks.*3
• Slide switch : You slide to left and right position once at least.
*1 If microcomputer can read the value less than 51 and the value more than 972 from A/D converter, it judges OK.
*2 Do not rotate JOG dial more than 45 turns. If you rotate it more than 45 turns, microcomputer can not judge properly.
If you turn JOG dial counterclockwise, microcomputer will ignore.
*3 Do not rotate the rotary selector more than 1365 turns. If you roatate it more than 1365 turns, microcomputer can not judge properly.
If you turn the rotary selector counterclockwise, microcomputer will ignore.
If you want to transit to next or previous page when operation check is not completed.
Once you switch to "All Light ON mode" or "All dimmer out mode" by pressing the rotary selector, you can transit to next or previous page.
F
For PLAY/PAUSE, CUE, BEAT FX ON/OFF and 8 PADs.
If top LEDs of the Channel level meter are blink or light off when these buttons are pressed, the check result is NG.
28 DDJ-400
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Service Mode – 3 Factory reset Mode

Mode outline
Following settings will be reset back to the factory default by pressing and holding both of left and right BEAT SYNC A
buttons for 1 sec.
Press and hold for 1 sec at the same time
C
Advanced Setting
Setting item Setting value
(Factory default setting = Bold)
Forcibly general MIDI controller mode.
1 MIDI controller setting
When rekordbox is launched, it will be in the appropriate mode to function of rekordbox dj.
Monaural
2 Master output in monaural or stereo setting
Stereo
Peak limiter is disabled.
3 Master output peak limiter setting
Peak limiter is enabled.
Demo mode is disabled.
Demo mode starts when there is no operation for 1 minute.
4 Demo mode setting
Demo mode starts when there is no operation for 5 minutes.
Demo mode starts when there is no operation for 10 minutes. D
When both of left and right BEAT SYNC buttons are pressed and held at the same time, LEDs of these buttons will light on.
After factory reset is completed, all PADs will light on in red.
When factory reset fails, left and right BEAT SYNC buttons will blink.
Service Mode – 4 Voltage value display Mode

This mode is for design development. It is not used in service.
E
Service Mode – 5 Voltage value fluctuation range check Mode

This mode is for design development. It is not used in service.
DDJ-400 29
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Service Mode – 6 Cross fader calibration Mode

Mode outline
A
This mode adjusts the cross fader.
Advanced Setting
When this mode is entered, PAD8 of left deck and PAD5
of right deck light on. And HP CUEs of both deck light on.
[Operation procedures of cross fader calibration]
Move crossfader to the left edge, then press the PAD8 of

left deck.
-> PAD4 and PAD8 of left deck light on.
(MAX value of the crossfader is memorized at this time.)
C Move crossfader to the left edge,

then press the PAD8 of left deck.
Move crossfader to the right edge, then press the PAD5 of

right deck.
-> PAD1 and PAD5 of right deck light on.
(Min value of the crossfader is memorized at this time.)
Move crossfader to the right edge,

then press the PAD5 of right deck.
Press the CH1 HP CUE button and CH2 HP CUE button of both deck at the same time.
-> SAMPLER of left deck and HOT CUE of right deck
D
light on, too.
[Display when calibration procedure is not gone through]
(End of memorizing crossfader values.) When calibration procedure is not gone through, BEAT SYNC buttons of both
deck blink.
[Estimated errors]
• It occurs when CH1 HP CUE button and CH2 HP CUE button
of both deck are pressed without going through the
operation procedure 1 and 2.
• It occurs when the magnitude relationship between MAX
value and MIN value is wrong.
E When error occurred and re-calibration operation is needed,

press the SHIFT buttons to re-entry this mode.
[Display when calibration procedure is not gone through]

When calibration procedure is not gone through, BEAT SYNC
buttons of both deck blink.
By press the CH1 HP CUE button and CH2 HP CUE
button of both deck at the same time, crossfader
Timing BEAT SYNC LEDs blink : values are memorized to serial Flash ROM.
At normal boot mode, cross fader calibration mode of Service If left SAMPLER and right HOT CUE are light on,
Crossfader calibration process is completed properly.
Mode and Utility Mode.
[Error]
When an error occurs, HOT CUE of left deck and SAMPLER of right deck blink.
F
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Service Mode – 1 Version check Mode

Mode outline
This mode is to check the version of the firmware. Version is displayed using the deck LEDs. Same as Service Mode - 1. A
Service Mode – 2 Measurement mode of the load of JOG dial

Mode outline
This is the measurement mode of the load of Jog dial.
When measurement mode starts, IN/4BEAT button of the [OUT] button LED is light on if measurement is OK.
left DECK will light on. [RELOOP/EXIT] button LED is light on if measurement is failed.
Advanced Setting
Spin the Jog dial swiftly.
To start measurement, maximum Jog dial rotation speed B
must be 7 times normal speed or higher.
If maximum speed does not reach 7 times normal speed, Indicates the number of Indicates the number of
measurement sessions measurement sessions
PAD LEDs (8 PADs) will blink several times. executed (up to 4 sessions). executed (up to 4 sessions).
Number of sessions will be displayed up to four sessions

on LED as follows.
End of 1st session HOT CUE lights on
End of 2nd session BEAT LOOP lights on
End of 3rd session BEAT JUMP lights on If maximum speed does not reach If maximum speed does not reach
7.0 times normal speed, all PAD 7.0 times normal speed, all PAD
End of 4th session SAMPLER lights on LEDs of the rotated side will blink. LEDs of the rotated side will blink.
(After the end of 4th session remain unchanged)
C
If measurement is OK, [OUT] button LED lights on.
If measurement failed, [RELOOP/EXIT] button LED is
light on. NG(Heavy) NG(Light) NG(Heavy) NG(Light)
When the measurement failed, PAD LED indicates as

follows.
NG(Heavy) PAD[5] lights on
NG(Light) PAD[8] lights on
When Jog dial is rotated swiftly, measurement for the top speed and the time required for slowdown.
When rotation speed of the Jog dial exceeds 7 times normal speed, time required for slowdown will be assessed
whether it is in the range or not. Result will be displayed on LED. D
Top speed : Top speed (when normal speed is defined as one rotation in 1.8 sec)
Time required for slowdown : Time required for the Jog dial to decrease its rotation speed from 3 times to 1.5 times normal speed
OK [OUT] button lights on
NG [RELOOP/EXIT] button lights on (Heavy : PAD[5] lights on / Light : PAD[8] lights on)
Number of measurement sessions executed is displayed up to 4 sessions.

Measurement can be continued 5 sessions and more, however the number of sessions will not be displayed.
When the session ended, result will be displayed on LED.
Regulation value is 90 ± 40 [msec].
E
If measurement result is NG (Heavy), turn the Jog dial by manually again (Running-in rotation).
If measurement result is NG (Light), remove the Jog dial once and wipe off the grease tentatively,
then apply the grease again and turn the Jog dial by manually (Running-in rotation).
(For details, refer to “7. DISASSEMBLY [4-1] Procedure for applying grease during reassembly of the Jog dial”.)
DDJ-400 31
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Service Mode – 3 Photo interrupter check Mode

Mode outline
A This is to check the status of photo interrupter.
When mode starts, IN/4BEAT button of the right DECK will [OUT] button LED is light on if measurement is OK.
[RELOOP/EXIT] button LED is light on if measurement is failed.
light on.
Advanced Setting
Spin the Jog dial swiftly.
To start measurement, maximum Jog dial rotation speed
must be 10 times normal speed or higher.
If maximum speed does not reach 10 times normal speed, Indicates the number of Indicates the number of
measurement sessions measurement sessions
no result will be displayed. executed (up to 4 sessions). executed (up to 4 sessions).
Number of sessions will be displayed up to four sessions

B on LED as follows.
End of 1st session HOT CUE lights on
End of 2nd session BEAT LOOP lights on
End of 3rd session BEAT JUMP lights on
End of 4th session SAMPLER lights on
(After the end of 4th session remain unchanged)
If measurement result is OK, [OUT] button LED lights on, If measurement failed, [RELOOP/EXIT] button LED lights on.
Clockwise
1 2 3 4 1 2 3 4
C JOG Pulse
P1
C D A B
JOG Pulse
P2
Counter clockwise
1 2 3 4 1 2 3 4
JOG Pulse
P1
C D A B
D JOG Pulse
P2
Time A - D will be memorized in each range of the speed: x16 – x14 / x11 – x9 / x6 – x4.
OK When phase relation is normal, and the minimum value of all the A - D is 10 usec or greater, ............................. [OUT] button lights on
and the time of [x11 – x9] (clockwise: "B"; counterclockwise: "A") is 200 usec or greater.
NG When none of these conditions described above is not satisfied. ........................................................................... [RELOOP/EXIT] button lights on
If measurement result is NG, re-attach the photo interrupter so as not inclination again.
32 DDJ-400
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6.2 ABOUT THE DEVICE

Device Information List (Other than General-Purpose Logic IC, Op-Amp IC)
ASSY Referrence No. Device Name Part No. Function A
IC202 REGULATOR MM3411A33N Regulator for V+3R3_SH
IC204 REGULATOR MM1856A50N Regulator for V+5_A
IC205 REGULATOR S-1172B1C-U5 Regulator for V+1R25_SH
IC207 DC/DC CONVERTER NJM2392M DC/DC converter for V+7/V-6
IC209 RESET IC S-80942CNMC-G9C POWER OFF DETECTOR IC for V_DET
IC210 REGULATOR MM1856A50N Regulator for V+5_HP
IC211 REGULATOR MM3411A33N Regulator for V+3R3_D
MAIN ASSY
IC406 SH UCOM R5S72670P144FP UCOM for LED,KEY,USB,Audio control
IC408 FLASH (16Mb) DYW**** FLASH Memory for SH UCOM (Firmware)
IC409 RESET IC S-80927CNMC-G8X Reset IC for SH UCOM
IC701 HEADPHONES ADC AK4387ET Headphone D/A converter
IC703 MASTER ADC AK4387ET Master D/A converter B
IC706 HEADPHONE AMP IC BH3547F Headphone Amplifier
IC708 MIC ADC AK5358AET MIC A/D converter
IC1201 JOG Touch UCOM DYW**** Touch detection for JOG DIAL
(Capacitance Sensors IC)
DSK1 ASSY
PC1201 PHOTO INTERRUPTER RPI-579N1 Rotation detection for JOG DIAL
IC2401 JOG Touch UCOM DYW**** Touch detection for JOG DIAL
(Capacitance Sensors IC)
PNL2 ASSY
Note : About DYW ****
Part number of " **** " changes every time the firmware is updated. C
DDJ-400 33
5 6 7 8
1 2 3 4
7. DISASSEMBLY
A
Note: Even if the unit shown in the photos and illustrations in this manual may differ from your product, the
procedures described here are common.
[1] Knobs and Volumes Location
x2 B
B
x 12 C
D D
C
x3 E
• Top view
A
N DAA1273 x1 B DAA1390 x 2 C DAA1324 x 12 D DNK6769 x 2 E
DAC2685 x 3
DAC2684 x 3
DNK6009 x 3
E
[2] Notes on Replacing Buttons
Notes Don’t cut
1 Cut Cut 2
1: Buttons (DAC2663, DAC2875, DAC3380,
DAC3408, DAC3416) are supplied as two
or three buttons connected. Cut them by
nipper before use.
2: Buttons (DAC3020, DAC3381, DAC3417)
are also supplied two buttons connected,
but don’t cut and use them as they are.
3 DAC3074
3: Button (DAC3074) is also supplied as two Deck section : Don’t cut
buttons connected. For the Deck section, Effect section :Cut(Use either of the two)
F don't cut the connection and use them as
they are. For the Effect section, cut and
use either of the two.
34 DDJ-400
1 2 3 4
5 6 7 8
A
[3] Disassembly
[3-1] Diagnosis : x 15
Remove the 15 screws. (BPZ30P120FTB) 9
13 6
Notes on assembling: Front
Attach the screws in the order as shown by 1 4
blue numbers.
After the attachment, push the four corners
14 10 2
of the upper-panel to confirm it doesn’t rattle. 7
B
Chassis

15 11 3
12 5 8
• Bottom view
If the product rattles, refer to “1.3 SERVICE : x5 terminal

1
NOTICE X How to modify when rattling
C
of product is occurred”.
Stay
Remove the Chassis. 2
Front 4 5
Remove the five screws. (BPZ30P100FTC) 3
Note on assembling:
Attach the screws in the order as shown by

orange numbers.
Lift up the FFC side of the Stay (with the MAIN

ASSY), draw the rear side terminal out from the D
hole of the Control Panel, and then remove the
Stay.
Note: Pay attention to the three FFCs

and one jumper wire connected.
Reverse the Stay (with the MAIN ASSY).

Note MAIN ASSY
4: Before turning the power on, lay the
insulation sheet (about 260 x 120 mm)
under the Stay. E
4
insulation sheet
Diagnosis Stay
DDJ-400 35
5 6 7 8
1 2 3 4
A [3-2] MAIN ASSY,

HPJK ASSY
Remove the Chassis and Stay.
(Refer to “[3-1] Diagnosis” .) : x4
When removing only the HPJK ASSY, removal
of the Stay is not necessary.
(Refer to step to of this section.)
----------------------------------------------------------------- Stay
CN102
Disconnect the three connectors.
Remove the four screws. (BPZ30P100FTC)
B
Note on assembling: 2 CN103
orange numbers.
Remove the MAIN ASSY (with the Stay) and 4

the HPJK ASSY. 3 CN101
1
Note: Two PCBs are connected with jumper
wire. HPJK ASSY
MAIN ASSY
Front
Disconnect the connector and then remove

the HPJK ASSY.

Note: Connector has a lock mechanism.
CN1601
HPJK ASSY (side-A)
D
: x5
Remove the five screws. (ASZ26P050FTC)

Note on assembling:
blue numbers.
2 3
Remove the Nut (M12). (NKX2FNI)
Remove the screw. (BPZ30P080FTB)
1 MAIN ASSY
Remove the screw. (DBA1340) 4
E Remove the MAIN ASSY from the Stay.

Stay
5
36 DDJ-400
1 2 3 4
5 6 7 8
[3-3] DCK1 ASSY A
Remove the Knob/PLS. (DNK6769)

Note: It is easily removed with a thin ribbon.

thin ribbon

B
Remove the two Knob/PLSs. (DAA1324)

Note: It is easily removed with a dessert spoon.
-----------------------------------------------------------------
Remove the Chassis.
: x8 : x 22
(Refer to step , of “[3-1] Diagnosis” .) 4
8 1
Remove the MAIN ASSY and HPJK ASSY.
(Refer to “[3-2] MAIN ASSY, HPJK ASSY” . ) 1 3 18 13 C
----------------------------------------------------------------- Plate
Remove the eight screws (BPZ30P100FTC)

16
and then remove the two Plates. 2 4 5
Note on assembling: Asetate Tape
Attach the screws in the order as shown by 19
orange numbers. 9
5
Remove the 22 screws (BPZ30P100FTC)
7
and then remove the DCK1 ASSY.
Notes on assembling: 5 7 DCK1 ASSY D
Attach the screws to the Control Panel in a 10 2
flat state (For details, refer to “1.3 SERVICE
Plate
NOTICE X How to modify when rattling
6 8 20 12
of product is occurred”) and in the order 17
as shown by blue numbers.
Take care not to follow the order shown by 21 14
the silk, which are different.
5: When replacing the DCK1 ASSY, or when
Asetate Tape on the side-B is removed,
11 22 6 15 3
paste new Asetate Tape. (For details, refer
to “1.3 SERVICE NOTICE X Paste Front E
Asetate Tape on the back face of PCB”.)
• Bottom view
Disconnect the connector, and remove the

39P FFC (DDD1858). FFC (DDD1858)

DCK1 ASSY (side-A)
F
CN1001
DDJ-400 37
5 6 7 8
1 2 3 4
A [3-4] PNL2 ASSY, 6 : x 10

BRWS ASSY,
CRFD ASSY
Remove the Knob/PLS. (DNK6769)
Note: It is easily removed with a thin ribbon.
Remove the Dial Knob S (B). (DAA1273)
Note 6 adhesive tape
6: As the dessert spoon
cannot be applied
for this knob, apply
B
the adhesive tape
around to remove it.
When removing only
the BRWS ASSY,
this is the only Knob to be removed.
(Refer to step to of this section.)
Remove the three Slider Knobs.

Notes: Three Slider Knobs have lock mechnisms.
(Refer to below)
7: When removing only the CRFD ASSY, remove
C only Slider Knob of near side. 7
(Refer to step , to of this section.)
Remove the 10 Knob/PLSs. (DAA1324)
Note: It is easily removed with a dessert spoon.
Remove the two Knob. (DAA1390)
Disassembly / Assembly of the Slider Knob

Push up the lower edge of the Slider Knob 2
Tweezers
with tweezers and then remove the Slider
Knob 2.
D Note

8: Push up of the Slider Knob 2 is only
possible from one side.
Remove the Slider Knob 1 upward.
Slider Knob 1
Remove the Stopper/SLD horizontally. Protective
Notes on assembling material Slider Knob 2 Stopper/SLD
9: Don't insert the Stopper/SLD from above.
8 9
10: Pay attention to the direction of each Knob
and Stopper.
10
Slider Knob 2
Slider Knob 1 Push up possible side Push up not possible side
10 Mounting direction for each Stopper/SLD.
Right side Right side
Bottom side of the Slider Knob 1

F Direct the concave side toward the Rear side
opposite side from the Stopper/SLD.
Stopper/SLD Front
38 DDJ-400
1 2 3 4
5 6 7 8
Remove the Chassis. A

(Refer to step , of “[3-1] Diagnosis” .) : x8 : x3 : x5 : x 34
Remove the MAIN ASSY and HPJK ASSY.
(Refer to “[3-2] MAIN ASSY, HPJK ASSY” . ) BRWS ASSY
3 4
Front
When removing only the BRWS 1 2
ASSY, removal of the HPJK ASSY
is not necessary. 5
5
(Refer to step , to of this 1 29 25 18 1 3
section.) 8 11
When removing only the CRFD 17
ASSY, removal of the MAIN ASSY 23
is not necessary.
Plate 2 4 B
33
(Refer to step , , to of 19
this section.)
4
----------------------------------------------
11
Remove the eight screws 2 21 12 14 Asetate Tape
(BPZ30P100FTC) and then 6
remove the two Plates.
Note on assembling: PNL2 ASSY
9 5 7
Attach the screws in the order
as shown by orange numbers. 34 24 13 Plate
30 28
Remove the three screws. 6 8 C
(BPZ30P100FTC)
15
Note on assembling: 31 22
26 20 16
Attach the screws in the order
as shown by pink numbers.
Remove the five screws. 3 32 7 27 10
1 2
(BPZ30P100FTC)
CRFD ASSY
Note on assembling:
Attach the screws in the order as shown by violet numbers. 3 • Bottom view
Remove the 34 screws (BPZ30P100FTC) and then remove
the PNL2 ASSY (with the BRWS ASSY and CRFD ASSY). D
Notes on assembling: FFC (DDD1859) BRWS ASSY
Attach the screws to the Control Panel in a flat state (For details,
refer to “1.3 SERVICE NOTICE X How to modify when rattling
of product is occurred”) and in the order as shown by blue numbers.
Take care not to follow the order shown by the silk, CN2001
which are different.
11: When replacing the PNL2 ASSY, or when Asetate
CRFD ASSY

CN1701
Tape on the side-B is removed, paste new Asetate Tape.
(For details, refer to “1.3 SERVICE NOTICE slit
X Paste Asetate Tape on the back face of PCB”.) FFC
Remove the two connectors and then remove the CN2002 (DDD1860) E
BRWS ASSY and CRFD ASSY.
Note: Two connectors have lock mechanisms. CN1801 PNL2 ASSY (side-A)
Disconnect the two connectors, and remove the 31P

FFC (DDD1860) through the slit of the PNL2 ASSY.

[3-5] HLD1 ASSY
1 3 4 2
Remove the Chassis. (Refer to step , of “[3-1] Diagnosis” .)
---------------------------------------------------------------------------------------
HLD1 ASSY
Remove the four screws (BPZ30P100FTC) and then remove
F
the HLD1 ASSY.
Notes on assembling: PNL2 ASSY
Attach the screws in the order as shown by blue numbers. Front
DDJ-400 39
5 6 7 8
1 2 3 4
A [3-6] Jog Dial Section

Remove the Chassis.
(Refer to step , of “[3-1] Diagnosis” .)
When you remove the Jog dial section, it is not necessary to remove the each board ASSY.
Figures show only the Right DECK side, but the Left DECK side is similar, too.
-----------------------------------------------------------------
Remove the Washer on the board side
(YC60FAC).
jig
Remove the Washer. (WA62D095D050)
Stand the Main Unit vertically, and then push Washer Washer
the shaft of Jog Dial peaking from the (YC60FAC) (WA62D095D050)
B
bearing.

Pull out the Jog Dial from the upper-panel,
and then remove it.
Remove the Washer (WA62D095D050) shaft
from the shaft of the Jog Dial.
Note on assembling:
Wipe old grease off, and then apply new
grease. • Bottom view
(Refer to “[4-1] Procedure for applying
C
grease during reassembly of the Jog
Dial”.)
Jog Dial
-----------------------------------------------------------------
shaft bearing
For Disassembly/Assembly of Washer (YC60FAC)
Use the jig. (Tapered snap ring pryor is shaft
recommended.)

tapered
Washer Open the jig.

(YC60FAC) Washer
(WA62D095D050)
E
shaft
Jog Dial
40 DDJ-400
1 2 3 4
5 6 7 8
A
[4] Notes on Assembling
[4-1] Procedure for applying grease during reassembly of the Jog Dial
Note: After the Jog Dial is removed, carefully wipe off the grease from the Jog Dial, as well as from the shaft bearing of the
Control Panel, then apply new grease, in the following manner:
Grease to be used: GEM1100
(1) Apply grease to the tip and base of the shaft of the Jog (3) Apply grease lightly to the shaft bearing of the Control
Dial one round each. Panel up to the depth of approximately 10 mm from the
B
upper-panel side. Then turn the Control Panel over and
shaft apply grease from the opposite side in the same manner.
shaft bearing
Jog Dial
Control Panel
C
• Top view
(2) Insert the Washer (WA62D095D050) on the shaft and

place it at the base of the shaft.
shaft bearing
Washer
(WA62D095D050) D
shaft • Bottom view
Jog Dial
(4) Turn the Control Panel over again, then apply a small
amount of grease to one point of the shaft bearing on E
the upper-panel side.
shaft bearing
• Top view
F
DDJ-400 41
5 6 7 8
1 2 3 4
A (5) Insert the Jog Dial in the shaft bearing while turning it. (8) Fit the Washer (YC60FAC) on the groove of the shaft.
jig
Washer
Jog Dial (YC60FAC)
shaft
shaft
B
Jog Dial
Washer must be fit rightly on the shaft groove without
slanting, etc.
OK
C
groove
(6) Turn the Control Panel over, and then wipe off the
NG
excess grease.
grease
D
(9) Turn the Control Panel over, and then check if the Jog
shaft Dial rotates properly.
(10) Perform manual running-in rotations of the Jog Dial,

following the procedure below.
Turn the Jog Dial manually 50 rotations.
Perform failure judgment of the Jog Dial.
• Bottom view For details of the measurement method, refer to
“ -2: Measurement mode of the load of JOG dial”
in “6-1. SERVICE MODE.”
E (7) Insert the Washer (WA62D095D050) on the shaft. -1 In the case of failure because of excessive load,
repeat the following procedure until a good result is
obtained in failure judgment.
Manually turn the Jog Dial 50 rotations then
perform failure judgment of the Jog Dial again.
-2 In the case of failure because of insufficient load,
apply grease again.
Washer (Repeat the above procedures from Step (1).)
(WA62D095D050)
Note:
After removing the Jog Dial, wipe off the grease tentatively.
F
42 DDJ-400
1 2 3 4
5 6 7 8
[4-2] Styling of the FFCs and cables A
12: Styling of the three FFCs follows the right

photo. MAIN ASSY
For folding, refer to “[4-4] Folding the
FFCs”.
13: Styling of the jumper wire between the MAIN
ASSY and HPJK ASSY follows the guide of
the silk on side-B of the DCK1 ASSY.
12
12
12 FFC (DDD1859)
FFC (DDD1858) B
FFC (DDD1860)
Front
HPJK ASSY 13
jumper wire
14: When styling both jumper wires between
the PNL2 ASSY and BRWS ASSY, and • Bottom view
between the PNL2 ASSY and CRFD ASSY,
let the extra length stick out from the
BRWS ASSY
bottom (Chassis) face.
jumper wire 15
Asetate Tape C
15
BRWS ASSY
Asetate Tape
14
PNL2 ASSY
Front 13
PNL2 ASSY Guide for jumper wire
jumper wire PNL2 ASSY
D
DCK1 ASSY
14
CRFD ASSY
CRFD ASSY
Front
15: When replacing the Asetate Tape on side-B • Bottom view

of the DCK1 ASSY or PNL2 ASSY, refer to
“1.3 SERVICE NOTICE X Paste Asetate
Tape on the back face of PCB”. E
Control Panel
[4-3] Sheet, Packing/TMP

16
16: When replacing the Control Panel, or when Sheet
16 16
the Sheet (DEC3795) and/or Packing/TMP Packing/TMP Packing/TMP
inside the Control Panel is damaged, apply
or replace them with new Sheet and/or
Packing/TMP.
Front
DDJ-400 43
5 6 7 8
1 2 3 4
A [4-4] Folding the FFCs

When replacing the FFCs, fold them as shown in the drawing below.
• DDD1858 39P Mountain fold Valley fold

120
38
DCK1 ASSY
MAIN ASSY
Reinforcement board border

Fold toward the reinforcement board
78
C Fold toward the reinforcement board
• DDD1859 25P
87
60
MAIN ASSY
PNL2 ASSY

D
40
• DDD1860 31P
PNL2 ASSY
140
82
E

MAIN ASSY
52
F Reinforcement board border
44 DDJ-400
1 2 3 4
5 6 7 8
8. EACH SETTING AND ADJUSTMENT

8.1 NECESSARY ITEMS TO BE NOTED
After repairing, be sure to check the version of the firmware, and if it is not the latest one, update to the latest version. A
Perform the each item when the following parts or PCB Assemblies are replaced.
• IC and PCB ASSY storing for firmware / • Cross fader calibration

user setting value / cross fader calibration value (6.1 SERVICE MODE : -6 Cross fader calibration mode)
FLASH ROM (IC408: MAIN ASSY) • Confirmation of the version of the firmware
MAIN ASSY • Updating to the latest version of the firmware
• Be changed user setting to condition before the repair
(when be possible)
• Jog dial • Judging the quality of the Jog dial load

(6.1 SERVICE MODE : -2 Measurement mode of the load of B
Jog dial)
• PC1201, PC1202, PC2401, PC2402 • Judging the quality of mounting and connection of the
(DCK1 ASSY, PNL2 ASSY) photointerrupter
(6.1 SERVICE MODE : -3 Photo interrupter check mode)
• Cross fader related parts • Cross fader calibration

(6.1 SERVICE MODE : -6 Cross fader calibration mode)
DDJ-400 45
5 6 7 8
1 2 3 4
8.2 UPDATING OF THE FIRMWARE

Confirmation of the Firmware Version
[How to confirm the firmware version on Windows] [How to confirm the firmware version on Mac]
A
1. Right-click DDJ-400 in the [Sound, video, and game 1. While holding down the [Option] key on the keyboard,
controllers] of Device Manager and select the [Properties]. open the Apple Menu and select the [System Information].
2. Select the [USB] in the item of [Hardware] and confirm

the firmware version by click [DDJ-400].
C
In the example shown below, version number is 0.40.
2. Select the [Details] tab and then select the [Hardware Ids]
of property.
.
3. Version number is [XXXX] of [REV_XXXX] in the character

string following [USB\VID_2B73&PID_0026 &].
In the example shown below, version number is 0.40.
E
46 DDJ-400
1 2 3 4
5 6 7 8
Updating of the Firmware

Connect this main unit to the PC / Mac with a USB cable, and update it by executing a dedicated update program. A
File name
Windows: DDJ-400_vxxx.exe * xxx is the version number. If it is Ver1.00,
it is DDJ-400_v100.exe / DDJ-400_v100_MAC.dmg
Mac: DDJ-400_vxxx_MAC.dmg * In the case of Mac, double-click the dmg file and icon will appear so execute it.
Note: Please close all DJ applications such as rekordbox when updating.
Update procedure About main unit display
When starting, select the language and click [OK].
Confirm the version and click [Start].

Blinking
L R L R L R
UPDATE being
UPDATE timeout Checksum error
processed normally
Light ON Light OFF
Wait until the progress bar reaches 100%.

When it reaches 100%, automatically restarts.
L R L R L R L R
D
Flash memory Flash memory
UPDATE normal completion -> Power OFF
write error validation error
Update application side error display

Application
Error content
error ID
Update file does not exist 0x0E01
File memory allocation error 0x0E02
File size is different. 0x0E03
* Correspondence after update failure E
Invalid version value in file 0x0E04
If an error occurs during firmware update, after restartup CRC mismatch in file 0x0E05
(USB cable inserted/removed), it startup in "Update Mode". Version value is unexpected 0x0E11
In the "Update Mode", All left and right CH level meters blink USB is not connected before communication starts 0x0E21
and the unit does not migrate to normal mode. Different start modes 0x0E31
Please perform update from PC / Mac again in this state. Memory allocation error 0x0E32
If it still does not return to normal, it is possible UCOM Checksum mismatch 0x0E33
(IC406), FLASH ROM (IC408) and FLASH ROM peripheral Write error 0x0E34
parts are failed. Verify error 0x0E35
No reply will come. 0x0E36
USB was disconnected while updating 0x0E37
Send and receive unknown code 0x0E41
Time out - F
(Data transmission from the application is interrupted)
DDJ-400 47
5 6 7 8
1 2 3 4
8.3 ITEMS FOR WHICH USER SETTING ARE AVAILABLE

This unit is provided with user settable items, as shown below.
Although no serious operational problems occur even if data for such user settable items are cleared during repair, it is
A
recommended that you take note of those settings before starting repair.
Use the Check Sheet, to which you can transcribe the settings.
If the corresponding part or board ASSY is replaced for repair, change the user resettable settings to those noted on the Check
Sheet before starting repair. If resetting is not possible, when returning the repaired product, be sure to tell the customer that
the Utility settings have been cleared and will have to be reset, as required.
Operation
Item for Which User's Setting Value
Button Lighting LED Part Name
Setting is Available (Factory defalt setting = Bold)
Deck (Left)
Stereo/Monaural setting HOT CUE HOT CUE Stereo (Light ON)
Monaural (Light OFF)
Master output peak limiter BEAT LOOP BEAT LOOP Enable(Light ON)
B setting Disable (Light OFF)
MIDI controller mode setting BEAT JUMP BEAT JUMP When rekordbox is launched, it will be in the
appropriate mode to function of rekordbox dj
When rekordbox is not launched, general MIDI IC408
controller mode (Light OFF) (MAIN ASSY)
Forcibly general MIDI controller mode (Light OFF)
Demo mode setting PAD 1 PAD 1 Demo mode OFF
PAD 2 PAD 2 1 minute
PAD 3 PAD 3 5 minutes
PAD 4 PAD 4 10 minutes
C
Each of the above items can be set in Utilities modes.
To enter Utilities mode,
while pressing both SHIFT and PLAY/PAUSE buttons on the left deck, connect the USB cable to the main unit
(to turn on the unit).
For changing the settings, refer to the operating instructions of the unit.
Sheet for confirmation of the user setting

Stereo/Monaural setting Master output peak limiter setting MIDI controller mode setting
Stereo Monaural Enable Disable Prioritize Forced
D rekordbox launch MIDI controller
Demo mode setting

Demo mode OFF 1 minute 5 minutes 10 minutes
48 DDJ-400
1 2 3 4
5 6 7 8
9. EXPLODED VIEWS AND PARTS LIST

NOTES: Parts marked by “NSP” are generally unavailable because they are not in our Master Spare Parts List.
The mark found on some component parts indicates the importance of the safety factor of the part. A
Therefore, when replacing, be sure to use parts of identical designation.
Screws adjacent to mark on product are used for disassembly.
For the applying amount of lubricants or glue, follow the instructions in this manual.
(In the case of no amount instructions, apply as you think it appropriate.)
9.1 PACKING SECTION
D
Front
Joint
(1) PACKING SECTION PARTS LIST

Mark No. Description Part No. Mark No. Description Part No.
NSP 1 Polyethylene Bag AHG7117 6 Packing Pad DHA1978

NSP 2 Warranty See Contrast table (2) 7 Packing Pad DHA1979
3 USB Cable DDE1150 8 Partition/ACC DHC1085
4 Operating Instructions See Contrast table (2) 9 Packing Case See Contrast table (2) E
(Quick Start Guide) 10 Master Carton See Contrast table (2)

5 Packing Sheet AHG7053
NSP 11 Leaflet DRM1410
NSP 12 License Key Label ASSY DXA2304
(2) CONTRAST TABLE

SXJ and XJCN are constructed the same except for the following:
Mark No. Symbol and Description SXJ XJCN
NSP 2 Warranty DRY1270 Not used
4 Operating Instructions (Quick Start Guide) DRH1505 DRH1506
9 Packing Case DHG3628 DHG3629 F
10 Master Carton DHG3631 DHG3632
DDJ-400 49
5 6 7 8
1 2 3 4
9.2 EXTERIOR SECTION

• Bottom view
A
A B
C
B
Grease
(GEM1100)
D
B Grease
(GEM1100)
Asetate Tape A
25 x 40 mm
A
E E
Asetate Tape
10 x 65 mm
F
C
D B
Grease
(GEM1100) G
F
H
G
1/2 A
1/2
C I
D
G
2/2
2/2
• Bottom view 1/3
1/2 E
I
F
E C
Note 1/2
• For details of Grease application, refer to
“7. DISASSEMBLY [4-1] Procedure for applying
grease during reassembly of the Jog Dial”.
• For details of Acetate Tape paste, refer to
“1.3 SERVICE NOTICE X Paste Asetate Tape H
on the back face of PCB”.
• For splitting buttons, refer to “7. DISASSEMBLY D
2/2
[2] Notes on Replacing Buttons”.
• If product rattles, refer to “1.3 SERVICE NOTICE
F
X How to modify when rattling of product is
occurred”.
50 DDJ-400
1 2 3 4
5 6 7 8
(1) EXTERIOR SECTION PARTS LIST

Mark No. Description Part No. Mark No. Description Part No.
1 MAIN ASSY DWX4152 31 SW Cap DAC2753

2 DCK1 ASSY DWX4153 32 Knob/PLS DNK6769 A
3 HPJK ASSY DWX4155 33 Panel DAH3210
4 BRWS ASSY DWX4156 34 Control Panel DNK6765
5 CRFD ASSY DWX4157 35 Chassis DNK6764
6 HLD1 ASSY DWX4158 36 Packing/TMP DEC3392

7 PNL2 ASSY DWX4154 37 Sheet DEC3795
8 FFC DDD1858 38 Plate/CND DNH3137
9 FFC DDD1859 39 Stay DNH3354
10 FFC DDD1860 40 Plate DNH3353
41 Knob DAA1390 B
11 Rubber Foot VEB1349
12 Plate DAH3209 42 Screw ASZ26P050FTC
13 Gasket/JOG DEC3539 43 Screw BPZ30P100FTC
14 Ds Tape/JOG DEH1042 44 Screw BPZ30P120FTB
15 Jog Dial DNK6763 45 Screw BPZ30P080FTB
16 Dial Knob S (B) DAA1273 46 Screw (M3 x 5) DBA1340

17 Knob/PLS DAA1324 47 Nut (M12) NKX2FNI
18 Slider Knob 1 DAC2684 48 Washer WA62D095D050
19 Slider Knob 2 DAC2685 49 Washer YC60FAC
20 Stopper/SLD DNK6009 50 Button DAC3416
C
21 Button/LOP DAC3074 NSP 51 Name Label See Contrast table (2)

22 Button/MT DAC2875
23 Button/CAL DAC3020
24 Button DAC3408
25 Button S (Black) DAC2663
26 Button DAC3417
27 Button DAC3151
28 Button DAC3381
29 Button DAC3380 D
30 Button DEB2063
(2) CONTRAST TABLE

SXJ and XJCN are constructed the same except for the following:
Mark No. Symbol and Description SXJ XJCN
NSP 51 Name Label Not used DRW2768
DDJ-400 51
5 6 7 8
1 2 3 4
52 DDJ-400
1 2 3 4

DDJ-400 DJ Controller Service Manual (QRT1023)

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DDJ-400 DJ Controller Service Manual (QRT1023)

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DDJ-400 DJ Controller Service Manual (QRT1023)

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ORDER NO.

DDJ-400 SXJ DC 5 V (USB bus power only)

DDJ-400 XJCN DC 5 V (USB bus power only)

2018 Pioneer DJ Corporation

1.2 NOTES ON REPLACING

Lubrication during Reassembly of the Jog Dial

1.3 SERVICE NOTICE

How to modify when rattling of product is occurred

Paste Acetate Tape on the back face of PCB

Acetate Tape Acetate Tape C

PNL2 ASSY DCK1 ASSY

3. BASIC ITEMS FOR SERVICE

C Noise Volume fluctuating

3.2 JIGS LIST

Lubricants and Glues List

SEVICE CHECK SHEET

• Next mode by pressing button (Right DECK)

3.3 PCB LOCATIONS

Mark No. Description Part No.

NSP 1..PNL1 ASSY DWM2684

1..PNL2 ASSY DWX4154

1 GNDD (GNDD_BRWS) 25 25 GNDD

CN2002 CN102 VKN1262

4.1 OVERALL WIRING DIAGRAM

4.2 BLOCK DIAGRAM

S-80927CNMC-G8X / xRST MM3411A33N V+3R3_SH S -1172B1C-U5

TC74VHC08FK DAC_CDTI DSS1204-

MIXER SECTION CN1001 CN101 7,5 DECK2 SECTION

TEMPO1_0 (MT) TEMPO2_0 (MT)

PC1201 IRQ IRQ

DYW**** JOG_TCH1 JOG_TCH2 DYW****

GPIO GPIO GPIO GPIO GPIO

C DCK1 ASSY D PNL2 ASSY

VOLTAGE DETECTION CIRCUIT

Initialize Ucom Registers

Load Initial Program

Load Main Program

Create and Start Tasks

Wait 600ms for Stable

Wait 100ms for Stable

Identify the PIC Ucom

Wait for 55ms

Turn HP_AMP_MUTE OFF

Start FAULT_DET Detecting

Fix the Boot Mode

E Initialize Peripheral Modules Start

Wait 300ms for Stable

Continued on next page

SH PIC (Left&Right) DAC (Master) DAC (HeadPhone) A

Wait 10ms for Stable

Turn DAC Reset OFF B

Wait 10ms for Stable

Turn DAC Reset ON

Wait 10ms for Stable

Turn DAC Reset OFF

Set DAC Proper

Wait 3000ms for

Turn A_MUTE OFF

Check if this board is

DYW JOG_TCH1 JOG_TCH2 DYW

Service Mode Service Mode

How to enter Service Mode How to enter Service Mode

Service Mode Service Mode

Check the PIC microcomputer. 1 Check the PIC microcomputer. 1

Service Mode – 1 Version check mode

Service Mode – 2 Check mode of the buttons, knobs, etc

Service Mode – 3 Factory reset Mode

Service Mode – 4 Voltage value display Mode

Service Mode – 5 Voltage value fluctuation range check Mode

Service Mode – 6 Cross fader calibration Mode