K Service Source

Macintosh TV
K Service Source

Basics
Macintosh TV
Basics Overview - 1

Overview
This manual contains
complete repair procedures
for the Macintosh TV shown
at left.

Figure: Macintosh TV
K Service Source

Specifications
Macintosh TV
 Specifications Processor - 1

Processor

CPU Motorola 68030 microprocessor

32 MHz
Built-in memory management unit (MMU)
Coprocessor
Socket for optional math coprocessor
 Specifications Memory - 2

Memory

RAM 4 MB of dynamic RAM on board

Expandable to 8 MB (100 ns or faster SIMMs)
72-pin DRAM SIMM connector

ROM 1 MB of ROM, expandable to 2 MB

PRAM 256 bytes of clock/calendar/parameter memory

Long-life lithium battery

VRAM 512K of VRAM on board (displays up to 256 colors or 8-bit

color)
 Specifications Disk Storage - 3

Disk Storage

Floppy Drive Internal 1.4 MB Apple SuperDrive

Hard Drive 3.5-inch, internal 160 MB SCSI hard drive

CD-ROM Drive Internal AppleCD 300i, double-speed CD-ROM drive

 Specifications I/O Interfaces - 4

I/O Interfaces

Serial Two RS-232/RS-422 serial ports; mini DIN-8 connectors

SCSI One SCSI parallel port; DB-25 connector

Connects up to six external SCSI devices

Apple Desktop Bus Two Apple Desktop Bus (ADB) ports; mini DIN-4 connectors
Maximum of three ADB devices recommended
Maximum current draw: 500 mA
(Mouse draws 10 mA, keyboard draws 25 mA)
 Specifications I/O Interfaces - 5

Infrared Receiver For remote control

Sound Sound-output port capable of delivering stereo sound

Sound-input port for monaural sound input
Front headphone jack capable of delivering stereo sound
 Specifications I/O Devices - 6

I/O Devices

Keyboard Supports all Apple Desktop Bus keyboards

Mouse Apple Desktop Bus Mouse II

New, ergonomic design

Speaker Adjustable sound control on front of bezel

 Specifications Sound and Video - 7

Sound and Video

Sound Generator Records at 11 kHz or 22 kHz sample rate

Plays back at 11 kHz or 22 kHz sample rate
Two speakers with enhanced stereo sound
Allows playback and recording of ordinary audio compact discs

Video Display 14-in. diagonal, 13-in. viewable screen

Trinitron CRT with high-contrast glass
.26-mm aperture grille pitch
640 pixels by 480 lines; 70 dpi
 Specifications Electrical - 8

Electrical

Line Voltage 100–240 VAC; Universal power supply

Frequency 47–63 Hz, single phase

Maximum Power 120 W

 Specifications Physical - 9

Physical

Dimensions Height: 17.9 in. (45.5 cm)

Width: 13.5 in. (34.4 cm)
Depth: 16.5 in. (42.0 cm)

Weight 41.5 lb. (18.9 kg)

 Specifications Environmental - 10

Environmental

Operating 50–104°F (10–40°C)

Temperature

Storage –30 to 116°F (–30 to 47°C)

Temperature

Relative Humidity 20–95% noncondensing

Altitude 10,000 ft. (3048 m) maximum (operating)

15,000 ft. (4572 m) maximum (non-operating)
 K Service Source

Troubleshooting
Macintosh TV
Troubleshooting General/ - 1

General
The Symptom Charts included in this chapter will help you
diagnose specific symptoms related to your product. Because cures
are listed on the charts in the order of most likely solution, try
the first cure first. Verify whether or not the product continues to
exhibit the symptom. If the symptom persists, try the next cure.
(Note: If you have replaced a module, reinstall the original module
before you proceed to the next cure.)

If you are not sure what the problem is, or if the Symptom Charts
do not resolve the problem, refer to the Flowchart for the product
family.

For additional assistance, contact Apple Technical Support.

 Troubleshooting Symptom Charts/Video - 2

Symptom Charts
Video
Screen is black, too 1 Adjust contrast button on front bezel.
dark, or too bright; 2 Adjust brightness. Use Brightness Control Panel.
audio and drive 3 Reset PRAM.
operate 4 Check yoke cable connection.
5 Perform video adjustments. Refer to “Video” in Adjustments
chapter.
6 Replace analog board.
7 Replace CRT.

Out of convergence 1 Perform convergence adjustment. Refer to “Convergence” in

(color bleeds from Adjustments chapter.
text or lines) 2 Replace analog board.
3 Replace CRT.
 Troubleshooting Symptom Charts/Video (Continued) - 3

Video (Continued)

Single vertical or Note: A thin, gray, horizontal line may be visible across the
horizontal line is bottom third of a lit screen. This line is inherent in the design of
displayed Trinitron monitors. Do not replace modules.

Otherwise,

1 Replace analog board.

2 Replace CRT.

Predominant color 1 Perform video adjustments. Refer to “Video” in Adjustments

tint or color cannot be chapter.
adjusted 2 Replace analog board.
3 Replace CRT if red, green, or blue cannot be turned off using
appropriate controls.
 Troubleshooting Symptom Charts/Video (Continued) - 4

Video (Continued)

Screen is bright and 1 Perform video adjustments. Refer to “Video” in Adjustments

audio is present, but chapter.
no video information 2 Replace analog board.
is visible 3 Replace chassis harness cable.
4 Replace CRT.

Picture breaks into 1 Perform video adjustments. Refer to “Video” in Adjustments

diagonal lines, or chapter.
picture rolls 2 Replace analog board.
vertically or
horizontally

Black screen spots Replace CRT.

(burnt phosphors)
 Troubleshooting Symptom Charts/Video (Continued) - 5

Video (Continued)

Screen jitters or 1 Verify that adjacent computer equipment is properly

flashes grounded. Move electrical devices away from monitor.
Temporarily shut off all fluorescent lights in area.
2 Check that all ground cables are secure.
3 Disconnect floppy drive, CD-ROM drive and hard drive.
4 Replace analog board.

Out of focus 1 Perform focus adjustment. Refer to “Focus” in Adjustments

chapter.
2 Replace analog board.
3 Replace CRT only if one part of display remains out of focus
despite adjustment of focus controls to their limits.
 Troubleshooting Symptom Charts/Video (Continued) - 6

Video (Continued)

Flashing or wavy Replace analog board.

screen, or monitor
emits high-pitched
noise

Raster size too short/ 1 Adjust horizontal or vertical size control. Refer to
tall or narrow/wide Adjustments chapter.
2 Replace analog board.

Linearity bad (size of 1 Perform video adjustments. Refer to “Video” in the

text/graphics differs Adjustments chapter.
at top, bottom, or 2 Replace analog board.
sides of screen)
 Troubleshooting Symptom Charts/Video (Continued) - 7

Video (Continued)

Raster tilted or 1 Verify that adjacent computer equipment is properly

shifted grounded. Move electrical devices away from monitor.
Temporarily shut off all fluorescent lights in area.
2 Perform appropriate geometric adjustments (see
Adjustments chapter).
3 Perform yoke adjustment. Refer to “Yoke” in Adjustments
chapter.
4 Replace analog board.

Raster distorted 1 Verify that adjacent computer equipment is properly

(barrel-shaped, grounded. Move electrical devices away from monitor.
corners not square, Temporarily shut off all fluorescent lights in area.
stretched or 2 Perform appropriate geometric adjustments (see
compressed at top of Adjustments chapter).
display, or sides not 3 Replace analog board.
perpendicular) 4 Replace CRT (only in rare instances).
 Troubleshooting Symptom Charts/Video (Continued) - 8

Video (Continued)

Raster not centered 1 Verify that adjacent computer equipment is properly

grounded. Move electrical devices away from monitor.
Temporarily shut off all fluorescent lights in area.
2 Adjust horizontal or vertical center control. Refer to
Adjustments chapter.
3 Replace analog board.
 Troubleshooting Symptom Charts/Floppy Drive - 9

Floppy Drive
Audio and video are 1 Replace bad disk with known-good disk.
present, but internal 2 Replace floppy drive.
floppy drive does not 3 Replace logic board. Retain customer’s SIMMs.
operate 4 Replace chassis harness cable.

Disk ejects; display 1 Replace bad system disk with known-good system disk.
shows icon with 2 Replace floppy drive.
blinking “X” 3 Replace logic board. Retain customer’s SIMMs.
4 Replace chassis harness cable.

Unable to insert disk 1 To eject previously inserted disk, insert opened paper clip
all the way into hole beside floppy drive.
2 Switch off system and hold mouse button down while
switching system on (to complete eject cycle).
3 Remove front drive bezel.
4 Replace floppy drive.
 Troubleshooting Symptom Charts/Floppy Drive (Continued) - 10

Floppy Drive (Continued)

Does not eject disk 1 Insert opened paper clip into hole beside floppy drive.
2 Switch off system and hold mouse button down while
switching system on (to complete eject cycle).
3 Remove front drive bezel.
4 Replace floppy drive.

Internal floppy drive 1 Replace bad disk with known-good disk.

runs continuously 2 Replace floppy drive.
3 Replace logic board. Retain customer’s SIMMs.
 Troubleshooting Symptom Charts/Hard Drive - 11

Hard Drive
Internal or external 1 Verify that SCSI loopback card is not attached.
hard drive does not 2 Verify that external drive is properly terminated.
operate 3 Replace hard drive.
4 Replace logic board. Retain customer’s SIMMs.

Works with internal 1 Verify that SCSI device ID switch setting on external device
or external SCSI is higher than 0. Also verify that ID switch setting on
device but does not external SCSI device does not duplicate ID switch settings on
work with both any other attached external SCSI devices.
2 Replace terminator on external SCSI device.
3 Replace SCSI select cable.
 Troubleshooting Symptom Charts/CD-ROM Drive - 12

CD-ROM Drive
CD-ROM drive does 1 Replace disc (if dirty or damaged).
not accept disc 2 Remove front drive bezel.
3 Replace CD-ROM drive mechanism.
4 Replace chassis harness cable.

Volume control does 1 Reset PRAM.

not operate correctly 2 Replace chassis harness assembly.

Macintosh cannot 1 Verify proper software installed.

mount CD-ROM drive 2 Start up from known-good Disk Tools or external SCSI device.
3 Replace CD-ROM drive mechanism.
 Troubleshooting Symptom Charts/Peripheral - 13

Peripheral
Cursor does not move 1 Check mouse connection.
2 If mouse was connected to keyboard, connect it to rear ADB
port instead. If mouse works, replace keyboard.
3 If mouse does not work in any ADB port, replace mouse.
4 Reset PRAM.
5 Replace logic board. Retain customer’s SIMMs.

Cursor moves, but 1 Replace mouse.

clicking the mouse 2 Replace logic board. Retain customer’s SIMMs.
button has no effect
 Troubleshooting Symptom Charts/Peripheral (Continued) - 14

Peripheral (Continued)

Cannot double-click 1 Remove extra system files on hard drive.

to open application, 2 Clear parameter RAM. Hold down <Command> <Option> <P>
disk, or server <R> keys during system startup but before “Welcome to
Macintosh” appears.
3 If mouse was connected to keyboard, connect it to rear ADB
port instead. If mouse works, replace keyboard.
4 If mouse does not work in any ADB port, replace mouse.
5 Replace logic board. Retain customer’s SIMMs.

No response to any 1 Check keyboard connection to ADB port.

key on keyboard 2 Replace keyboard cable.
3 Replace keyboard.
4 Replace logic board. Retain customer’s SIMMs.
 Troubleshooting Symptom Charts/Peripheral (Continued) - 15

Peripheral (Continued)

Known-good 1 Make sure that Chooser and Control Panel are set correctly.
ImageWriter or 2 Replace printer driver and system software with known-
ImageWriter II does good.
not print 3 Reset PRAM.
4 Replace printer interface cable.
5 Replace logic board. Retain customer’s SIMMs.

Known-good 1 Make sure that Chooser and Control Panel are set correctly.
LaserWriter does not 2 Replace printer driver and system software with known-
print good.
3 Reset PRAM.
4 Refer to Network and Communications manual.
 Troubleshooting Symptom Charts/Miscellaneous - 16

Miscellaneous
Clicking, chirping, 1 Replace analog board.
or thumping sound 2 Replace logic board. Retain customer’s SIMMs.

Smoke/odor 1 Inspect analog and logic boards for obvious signs of burnt
components.
2 Replace analog board.

No video, no audio, and 1 Connect power cord.

no drive operation 2 Switch power on.
3 Replace power cord.
4 Replace keyboard.
5 Replace analog board.
6 Replace logic board. Retain customer’s SIMMs.
 Troubleshooting Symptom Charts/Miscellaneous (Continued) - 17

Miscellaneous (Continued)

Screen shows “Sad 1 Replace RAM SIMMs on logic board.

Macintosh” icon and 2 Replace logic board. Retain customer’s SIMMs.
black vertical lines;
screeching sound

Headphone jack does 1 Verify that headphone jack is seated properly.

not operate correctly 2 Replace chassis harness assembly.

“Sad Macintosh” icon 1 Replace bad disk with known-good disk.

2 Remove all internal and external IDE and SCSI devices. If
flashing “?” appears, reconnect devices one at a time and
perform software troubleshooting on device that reproduces
the issue.
3 Replace RAM SIMMs on logic board.
4 Replace logic board. Retain customer’s SIMMs.
K Service Source

Take Apart
Macintosh TV
Take Apart Rear Housing - 1

Rear Housing Rear Housing

No preliminary steps are
required before you begin
this procedure.

± Warning: This product

contains high voltage and a
high-vacuum picture tube.
To prevent serious injury,
review CRT safety in
Bulletins/Safety.

Caution: Never use a

grounding wriststrap until
after discharging the CRT.
Take Apart Rear Housing - 2

Rear Housing 1 Using a torx

screwdriver, remove
the five screws.

2 Lift off the rear cover.

Take Apart Fan - 3

Fan Fan
Before you begin, remove
the rear cover.

±Warning: This product

contains high voltage and a
high-vacuum picture tube.
To prevent serious injury,
review CRT safety in
Bulletins/Safety.

Caution: Never use a

grounding wriststrap until
after discharging the CRT.Ê
Take Apart Fan - 4

Push out the two latches and

Latch
remove the fan assembly.

Fan

Latch
 Take Apart Analog Board - 5

Analog Board
Before you begin, do the
following:
• Remove the rear cover
• Discharge CRT
Analog Board • Remove anode cap

± Warning: This product

contains high voltage and a
high-vacuum picture tube.
To prevent serious injury,
review CRT safety in
Bulletins/Safety.

Caution: Never use a

grounding wriststrap until
after discharging the CRT.Ê
Take Apart Analog Board - 6

1 Disconnect the two

Degauss Panel
ground cables from the
degauss panels.

Ground Cable

Ground
Cable
Take Apart Analog Board - 7

2 Disconnect the infrared

receiver connector.

Infrared Receiver
Connector

WARNING:
High Voltage Areas
Take Apart Analog Board - 8

3 Disconnect the following

cables from the analog
board:
• Degauss cable from
BP2 (use a small
screwdriver to
release the latch)
• CRT cable from BD1

Cable 4 Remove the wires from

Retainer the cable retainer.

Replacement Note: If you

are replacing the analog
board, remove the cable
retainer and reinstall it on
the new board.
 Take Apart Analog Board - 9

5 Caution: Twisting,
bending, or applying
force to the video board
assembly could damage
the neck of the CRT. Be
CRT Board Assembly sure to pull the CRT
board assembly straight
off the CRT.

Remove the CRT board

assembly from the neck
of the CRT.
 Take Apart Analog Board - 10

6 Remove the analog board.

Replacement Note: Perform

the cutoff adjustment
whenever you replace the
analog board. See “Video” in
the Adjustments chapter.

Analog
Board
 Take Apart I/O Door - 11

I/O Door
No preliminary steps are
required before you begin
this procedure.

I/O Door
Take Apart I/O Door - 12

1 Remove the two screws

(if present).

2 Push down on the two

tabs and remove the I/O
door.
Tab

Tab I/O Door

Take Apart Logic Board - 13

Logic Board
Before you begin, remove
the I/O door.

Caution: You can access and

remove the Macintosh TV
logic board merely by
removing the I/O door at the
rear of the machine.
Although upgrading the logic
board is now extremely
easy, do not neglect to follow
proper ESD precautions:
use a grounded workbench
pad, and always wear a
Logic Board
grounding wriststrap.Ê
Take Apart Logic Board - 14

Pull out the logic board.

Logic
Board
Take Apart Tuner Assembly - 15

Tuner Assembly
Before you begin, remove
the following:
• I/O door
• Logic board

Tuner
Assembly
Take Apart Tuner Assembly - 16

1 Turn over the logic

board.

2 Using needlenose pliers,

carefully twist the
Mounting Tab mounting tab of the
tuner.
Take Apart Tuner Assembly - 17

3 Turn over the logic

board.

4 Pull straight up on the

Tuner Assembly tuner assembly and
remove it from the logic
Logic Board board.
Take Apart Drive Bezel - 18

Drive Bezel
No preliminary steps are
required before you begin
this procedure.

Drive
Bezel
Take Apart Drive Bezel - 19

Using a flat-blade
screwdriver, push up the
latch. Pull down and remove
the drive bezel.

Latch

Drive
Bezel
Take Apart Floppy Drive - 20

Floppy Drive
Before you begin, remove
the drive bezel.

Caution: You can access and

remove the Macintosh TV
floppy drive merely by
removing the drive bezel at
the front of the machine.
Although upgrading the
Floppy floppy drive is now
Drive extremely easy, do not
neglect to follow proper
ESD precautions: use a
grounded workbench pad,
and always wear a
grounding wriststrap.
Take Apart Floppy Drive - 21

1 Push down the latch and

pull out the floppy
drive.Ê

Floppy Drive
 Take Apart Floppy Drive - 22

Floppy Drive
2 Pull out the floppy
drive connector adapter.

3 Replacement Note: Be
Connector Adapter sure to reinstall the
floppy drive connector
adapter on the
replacement floppy
drive.
Take Apart Floppy Drive - 23

4 Remove the four

mounting screws and
remove the floppy drive
from the carrier.

Carrier
Take Apart Floppy Drive - 24

5 Pull out the sides of the

floppy drive shield, lift
the back of the shield,
and remove it from the
Floppy Drive Shield
floppy drive.

Floppy Drive
Take Apart CD-ROM Drive - 25

CD-ROM Drive
Before you begin, remove
the drive bezel.

Caution: You can access and

remove the Macintosh TV
CD-ROM drive merely by
removing the drive bezel at
the front of the machine.
Although upgrading the CD-
ROM drive is now
extremely easy, do not
neglect to follow proper
ESD precautions: use a
grounded workbench pad,
and always wear a
grounding wriststrap.
CD-ROM Drive
Take Apart CD-ROM Drive - 26

1 Pull up the latch and

pull out the CD-ROM
drive. Ê

CD-ROM
Drive

Latch
Take Apart CD-ROM Drive - 27

2 P ull out the CD

connector adapter and
the CD audio adapter.

Replacement Note: Be
sure to reinstall the CD
connector adapter on the
CD Connector Adapter
replacement CD-ROM
drive.

CD Audio Adapter
Take Apart CD-ROM Drive - 28

3 Remove the four

mounting screws and
remove the CD-ROM
drive from the carrier.

CD-ROM Drive Replacement Note: Replace

the carrier on the new CD-
ROM drive.

Carrier
Take Apart Hard Drive - 29

Hard Drive
Before you begin, remove
the I/O door.

Caution: You can access and

remove the Macintosh TV
Hard Drive hard drive merely by
removing the I/O door at the
rear of the machine.
Although upgrading the hard
drive is now extremely
easy, do not neglect to follow
proper ESD precautions:
use a grounded workbench
pad, and always wear a
grounding wriststrap.
Take Apart Hard Drive - 30

1 P ush down the latch and

remove the hard drive.

Hard Drive

Latch
Take Apart Hard Drive - 31

2 Pull out the hard drive

connector adapter.

Replacement Note: Be
sure to reinstall the
hard drive connector
adapter on the
replacement hard drive.

Hard Drive
Connector
Adapter
Take Apart Hard Drive - 32

3 Remove the four screws.

4 Remove the hard drive

from the carrier.

Carrier Replacement Note: Replace

the carrier on the new hard
drive.

Hard Drive
 Take Apart Chassis Harness Assembly - 33

Chassis Harness
Assembly
Before you begin, remove
the following:
• Drive bezel
• I/O door
• CD-ROM drive
• Floppy drive
• Hard drive
• Logic board
• Rear housing
• Analog board

Chassis Harness
Assembly
 Take Apart Chassis Harness Assembly - 34

±Warning: This product

contains high voltage and a
high-vacuum picture tube.
To prevent serious personal
injury or equipment
damage, review CRT safety
in Bulletins/Safety.
Latches
Chassis ±Warning: Never use a
Harness grounding wriststrap until
Assembly
after discharging the CRT.

1 Discharge the CRT.

Latches 2 Press in the four

latches and lift off the
chassis harness
assembly.
Take Apart Chassis Harness Assembly - 35

Chassis Harness Take Apart Strategy

Background
After product introduction, Apple Service adjusted the
service strategy for the chassis harness assembly in Mac
TV, LC 500 Series, and Performa 500 Series computers.
Originally, the chassis harness assembly was a single
service assembly. As of November 1994, the chassis
harness assembly is divided into several service piece parts.

Identifying the Chassis Harness Assembly

There are three slightly different chassis harness
assemblies and Apple service strategy varies with the type
of chassis. The three chassis harness assemblies differ
according to the combination of floppy and CD-ROM drives
they support.
Take Apart Chassis Harness Assembly - 36

• Chassis 922-1824 supports the auto-insert Apple

SuperDrive and CD-ROM drives earlier than the 300i+.
This chassis requires a floppy drive adapter, and the CD-
ROM connector bridge is about 1-1/2 inches above the
CD-ROM drive bay.
• Chassis 922-0557 supports the manual-insert Apple
SuperDrive and CD-ROM drives earlier than the 300i+.
This chassis uses a ribbon cable to connect the floppy
drive, and the CD-ROM connector bridge is about 1-1/2
inches above the CD-ROM drive bay.
• Chassis 922-0767 supports the manual-insert Apple
SuperDrive and the 300i+ CD-ROM drive. This chassis
uses a ribbon cable to connect the floppy drive, but the
CD-ROM connector bridge is only 1/2 inch above the CD-
ROM drive bay.
Take Apart Chassis Harness Assembly - 37

For more information, refer to Apple Service Guide,

Macintosh Computers, Vol. 3 (1994), page 110.

Service Parts Now Available for Chassis 922-1824 and

922-0557
076-0488 Shield Kit (EMI shielding)

922-1825 PCBA Front Panel (front panel control board)

922-1826 Speaker Assembly (speaker and wire)

922-0117 Screw

076-0489 Chassis Kit (bare chassis)

922-0503 FoxConn Cable Assembly (logic board connector

and cable assembly)
Take Apart Chassis Harness Assembly - 38

Service Parts Now Available for Chassis 922-0767

076-0488 Shield Kit (EMI shielding)

922-1825 PCBA Front Panel (front panel control board)

922-1826 Speaker Assembly (speaker and wire)

922-0117 Screw
Take Apart Chassis Harness Assembly - 39

Chassis Harness Take Apart Procedures

First remove the chassis harness assembly.

EMI Shields
1 Remove the EMI shields in this order: lower shield, front
drive and speaker shield, top panel shield.

2 Remove the front panel control board shield if it is

present.
Take Apart Chassis Harness Assembly - 40

Speaker Assembly
First remove the EMI
shields.

Caution: The speaker wire

connections on the chassis
cable bridge are very
fragile. Avoid removing or
replacing the speaker wires
unless you need to replace
the chassis or have isolated
the problem to the speaker
wires. (That is, replace and
test the speakers, front
panel control board, and
analog board first.)
Take Apart Chassis Harness Assembly - 41

1 Disconnect the speaker wire spade connector from the

back of the speaker.

2 Remove the Phillips screws from the front of the

speaker.

Replacement Note: Detach the replacement speaker from its

wires and connect the replacement speaker to the original
speaker wires.

Speaker Wires
Note: The speaker wire connectors are very fragile.

1 Look down on the chassis cable bridge and locate the

notches in the cable bridge on top of the wire connectors.

2 Using a jeweler's screwdriver, very gently press down

on the tab in the middle of the wire connector. You will
feel or hear a snap.
Take Apart Chassis Harness Assembly - 42

3 Slide out the wire connector.

Replacement Note: The analog board slides into the

computer and completes the connection to the speaker wires;
thus, the speaker wire connectors must sit securely in the
cable bridge.

4 Slide the speaker wire connector into its position in the

cable bridge and press up until the connector is secure.
You may need to use a jeweler's screw driver to adjust
the small metal tab in the center of the speaker wire
connector.
Take Apart Chassis Harness Assembly - 43

Front Panel Control Board

First remove the EMI
shields.

1 Disconnect the front

panel control cable.

2 Remove the Phillips

screw and remove the
board.
Take Apart Chassis Harness Assembly - 44

Logic Board Connector and Cable Assembly

First remove the EMI shields, speaker assembly, and front
panel control board.

Overview of removal procedures (Detailed steps follow the

overview.)

First disconnect all the connections from the top of the

chassis. Then route the cables through to the underside of the
chassis and disconnect the logic board connector.
 Take Apart Chassis Harness Assembly - 45

1 Stand at the front of the

chassis, looking down at
the top of the chassis,
and disconnect the
following in the order
listed: analog board
Hard connector, CD-ROM
CD-ROM
Connector Drive drive connector, and
Connector hard drive connector.
Left (The connector tabs
Analog Speaker
Cable operate much like large-
Board
Connector Connector scale SIMM slot
Right
Bridge Speaker connectors on logic
Cable Cable boards.)
Connector

Floppy Drive Connector

Take Apart Chassis Harness Assembly - 46

2 Route the analog board and the CD-ROM/hard drive

cables through the large square hole behind the CD-ROM
drive bay.

3 Push the floppy drive cable (if present) and front panel
control cable to the underside of the chassis.

4 Turn the chassis over and stand at the rear of the chassis.

5 Release the three tabs from the sides and center of the
logic board connector and remove the logic board
connector and cable assembly.
Take Apart Chassis Harness Assembly - 47

Overview of replacement procedures (Detailed steps follow

the overview.)

Connect the logic board connector to the underside of the

chassis, route the cables through the appropriate openings,
and connect the connectors on the top and front of the chassis.
After replacing the logic board connector and cable
assembly, replace the speakers, front panel control board,
and EMI shields.

1 Place the chassis with the underside facing up and the

speakers facing away from you.
 Take Apart Chassis Harness Assembly - 48

2 Arrange the logic board

connector and cable
assembly as shown.
Control 3 Face the connector slot of
Panel
Cable the logic board connector
Analog toward the rear and from
Board the back of the
Connector
connector route the CD-
Floppy
Drive ROM/hard drive,
Logic
Board Cable analog, and floppy drive
Connector
cables under the
connector. Extend the
CD-ROM
Drive Cable/ control panel connector
Hard Drive cable from the back of
Cable
the logic board connector
toward the front of the
chassis.
Take Apart Chassis Harness Assembly - 49

Logic Board Connector

and Cable Assembly

1 Slide the side extension

of the logic board
connector down the
front side of the small
keyed tabs. The logic
board connector will
snap into place.

Note: Be sure the center

tab snaps into place at
the same time.

2 Route the front panel

control cable through the
hole in the front of the
chassis
Take Apart Chassis Harness Assembly - 50

3 Route the floppy drive cable through its opening at the

back of the floppy drive bay.

4 Carefully route the analog and CD-ROM/hard drive

cables through the large opening behind the CD-ROM
drive bay

5 Turn over the chassis so that the top is up and the

speakers are at the front, facing you.

Important: Be sure to reconnect the CD-ROM, hard drive,

and analog connectors in the proper order. When you
position the CD-ROM, hard drive, and analog connectors, be
sure that the power cables are placed toward the outside of
the chassis and the data ribbon cables are placed toward the
inside of the chassis.

6 Locate the CD-ROM, hard drive, and analog connectors.

7 Position the CD-ROM connector with the connector slot

Take Apart Chassis Harness Assembly - 51

facing the front of the chassis and the power cables

facing toward the outside edge of the chassis. Slip the
connector extension through the slot in the side of the
chassis and slide the connector into place.

8 Position the hard drive connector with the connector slot

facing the rear of the chassis and the power cables facing
toward the outside edge of the chassis. Slip the connector
extension through the slot in the side of the chassis and
slide the connector into place.

9 Position the analog board connector with the connector

slot facing the rear and the power cables facing toward
the outside edge of the chassis. You will have to route the
cable under the connector (between the connector and the
cable bridge). Slightly push forward one of the keyed
tabs and slide the connector into place.
Take Apart Chassis Harness Assembly - 52

10 To replace the speakers, front control panel board, and

EMI shields, reverse the take-apart procedures above.
Pay attention to the caution regarding the fragility of the
speaker wire connectors and their replacement
procedures.
Take Apart CRT - 53

CRT CRT
Before you begin, remove
the following:
• Drive bezel
• I/O door
• CD-ROM drive
• Floppy drive
• Hard drive
• Logic board
• Rear cover
• Analog board
• Chassis harness assembly
 Take Apart CRT - 54

±Warning: This product

Mounting Screws
contains high voltage and a
high-vacuum picture tube.
Degauss To prevent serious injury,
Panel Degauss review CRT safety in
Panel
Bulletins/Safety.

±Warning: Never use a

grounding wriststrap until
after discharging the CRT.

1 Remove the four

mounting screws and
lift off the two degauss
panels.
 Take Apart CRT - 55

2 Lift off the CRT.

Replacement Note: Be sure

the infrared receiver cable
is not caught under the CRT.

CRT

Infrared
Receiver
Cable
Take Apart Infrared Receiver - 56

Infrared Receiver Infrared Receiver

Before you begin, remove
the following:
• Drive bezel
• I/O door
• CD-ROM drive
• Floppy drive
• Hard drive
• Logic board
• Rear cover
• Analog board
• Chassis harness assembly
• CRT
Take Apart Infrared Receiver - 57

±Warning: This product

Infrared contains high voltage and a
Receiver high-vacuum picture tube.
To prevent serious injury,
review CRT safety in
Bulletins/Safety.

±Warning: Never use a

grounding wriststrap until
after discharging the CRT.

Push out the two latches and

remove the infrared
receiver.
Take Apart Front Bezel - 58

Front Bezel Front Bezel

To remove the front bezel,
remove the following:
• Drive bezel
• I/O door
• CD-ROM drive
• Floppy drive
• Hard drive
• Logic board
• Rear cover
• Analog board
• Chassis harness assembly
• CRT
• Infrared receiver
Take Apart Front Bezel - 59

±Warning: This product

contains high voltage and a
high-vacuum picture tube.
To prevent serious injury,
Front Bezel review CRT safety in
Bulletins/Safety.

Caution: Never use a

grounding wriststrap until
after discharging the CRT.
 K Service Source

Additional Procedures
Macintosh TV
Additional Procedures Battery Verification - 1

Battery
Verification
Before you begin, remove
the following:
• I/O door
• Logic board

±Warning: If handled or
discarded improperly, the
lithium battery in the
Battery computer could explode.
Review battery handling and
disposal instructions in
Bulletins/Safety.
Additional Procedures Battery Verification - 2

Caution: Review the ESD

precautions in Bulletins/
Safety.

1 Set the voltmeter to the

Negative 10 volts DC scale.
Probe
2 Hold the positive probe
of the voltmeter to the
Positive positive end of the
Probe
battery and the negative
probe to the negative
end of the battery.

3 If the battery voltage is

below 3.0 volts, replace
the battery. Refer to
“Battery Replacement”
in this chapter.
Additional Procedures Battery Replacement - 3

Battery
Replacement
Before you begin, remove
the following:
• I/O door
• Logic board

±Warning: If handled or
discarded improperly, the
lithium battery in the
Battery computer could explode.
Review battery-handling
and disposal instructions in
Bulletins/Safety.
Additional Procedures Battery Replacement - 4

Caution: To prevent ESD

damage to components, wear
a grounding wriststrap and
use a grounded workbench
pad. Review the ESD
Cover precautions in Bulletins/
Safety.

1 Insert a small flat-

blade screwdriver into
Battery the top of the battery
Holder
holder cover and gently
push down and out with
the screwdriver to
release the tab.

2 Repeat on the other end

and remove the cover
from the battery holder.
Additional Procedures Battery Replacement - 5

3 Grasp the battery and

remove it from the
holder.

4 Return the battery to

Apple for proper
disposal. For battery
packaging and labeling
information, refer to the
instructions in
Bulletins/Safety.
K Service Source

Adjustments
Macintosh TV
 Adjustments Geometry - 1

Geometry
Before you begin, remove
the rear cover.

±Warning: This product

contains high voltage and a
high-vacuum picture tube.
To prevent serious injury,
review CRT safety in
Bulletins/Safety.

Adjustment WARNING:
Controls
High Voltage Areas
Adjustments Geometry - 2

Note: The controls on this

monitor require a small
hex-head plastic tool to
make adjustments. If the tool
is long, it will be too
flexible, which will make
fine adjustments difficult.
Use a short hex-head
plastic tool to minimize
flexing. Do not use metal
alignment tools—they are a
shock hazard.
Adjustments Geometry - 3

Vertical Center
1 Use Display Service
Utility to display the
All-White Screen All-White Screen test
pattern.
2 Using a hex-head plastic
adjustment tool, adjust
the vertical center (VS)
control until the raster
is centered (top to
bottom) in the display
area.
Adjustments Geometry - 4

Horizontal Center
Using a hex-head plastic
adjustment tool, adjust the
All-White Screen horizontal center (HS)
control until the raster is
centered (side to side) in the
display area.
Adjustments Geometry - 5

Vertical Size
1 Using a hex-head plastic
adjustment tool, adjust
the vertical height (VH)
All-White Screen
control until the raster
height is 7 inches (± 1/
8 inch) or 176 mm (± 2
mm).

2 Verify this height. If it

is off, repeat the
vertical size adjustment
and, if necessary, the
vertical center
adjustment.
Adjustments Geometry - 6

Horizontal Size
Note: Due to video features
and timing differences
All-White Screen across the Apple line of
Macintosh computers, the
width of the raster/image
area on the Macintosh TV
screen may vary up to 3/16
inch at each side of the
screen. Perform the
horizontal size adjustment
to set the display to its
proper width.
Adjustments Geometry - 7

Using a hex-head plastic

adjustment tool, adjust the
horizontal width (HW)
control until the raster is 9
1/4 inches (± 1/8 inch) or
235 mm (± 2 mm).
Adjustments Geometry - 8

Focus
1 Use Display Service
Utility to display the
Focus test pattern.
Focus
2 Using a hex-head plastic
adjustment tool, adjust
the focus control until
the Focus test pattern is
as clear as possible.

WARNING:
High Voltage Areas
 Adjustments Video - 9

Video
Before you begin, remove
the rear cover.

±Warning: This product

contains high voltage and a
high-vacuum picture tube.
To prevent serious injury,
review CRT safety in
Bulletins/Safety.

Note: Perform the cutoff

adjustment prior to
adjusting the white balance.

Adjustment WARNING:
Controls High Voltage Areas
Adjustments Video - 10

Replacement Note: Perform

the cutoff adjustment
whenever you replace the
CRT or the analog board.
Adjustments Video - 11

Cutoff
Note: Perform the cutoff
and white balance
adjustments after the
Gray Bars monitor has been on for at
least 10 minutes.

1 Use Display Service

Utility to display the
Gray Bars test pattern.

2 Press the Contrast Up

button and set screen
contrast to maximum.

Contrast Up Button
Adjustments Video - 12

3 Select the Brightness

Control Panel from the
Apple menu. Drag the
brightness control to
midrange.

4 Using a hex-head plastic

adjustment tool, set the
red (RB), green (GB),
and blue (BB)
background controls to
the full
counterclockwise
positions.
Adjustments Video - 13

Note: To set the green and

blue drive controls to their
3/4 position, turn the
controls to their full
clockwise position and then
turn back 1/4 turn
counterclockwise.

5 Set the green (GG) and

blue (BG) drive controls
clockwise to their 3/4
position.

6 Set the sub-contrast

control (SC) to its full
clockwise position.
Adjustments Video - 14

7 Using a hex-head plastic

adjustment tool, adjust
VG2 until the first bar
in the test pattern is
Gray Bars completely black and the
second bar is barely
visible.

8 Set the sub-contrast

control (SC) to the
center position.
Adjustments Video - 15

White Balance
Note: Perform the cutoff
and white balance
adjustments after the
Gray Bars
monitor has been on for at
least 10 minutes.

1 Use Display Service

Utility to display the
Gray Bars test pattern.

2 Press the Contrast Up

button and set screen
contrast to maximum.

Contrast Up Button
Adjustments Video - 16

3 Select the Brightness

Control Panel from the
Apple menu. Drag the
brightness control to
Gray Bars midrange.

4 Note the predominant

color.

5 Using a hex-head plastic

adjustment tool,
alternately adjust the
red (RB), green (GB),
and blue (BB)
background controls
until there is no
predominant color in
the four darkest bars.
Adjustments Video - 17

Note: The darkest bar must

remain completely black
throughout the rest of the
procedure. If you notice a
Gray Bars predominant color in the
darkest bar, readjust the
appropriate background
control.

6 I f necessary, adjust the

blue (BG) and green
(GG) drive controls
until there is no
predominant color in
the four brightest bars.

7 Check the four darkest

bars, and if necessary,
adjust the red (RB),
Adjustments Video - 19

• Model 246: 25 on the

red scale

Important: Over time, light

meter tolerance can vary. If
you doubt your meter’s
accuracy, verify the
readings with a known-good
light meter or photometer.
 Adjustments Convergence - 20

Convergence
Before you begin, remove
the rear cover.

Yoke Convergence ±Warning: This product

Controls
contains high voltage and a
CRT Video
high-vacuum picture tube.
Board To prevent serious injury,
review CRT safety in
Bulletins/Safety.

WARNING:
High Voltage Areas
 Adjustments Convergence - 21

1 Use Display Service

Utility to display the
Crosshatch I test
pattern.

Crosshatch I 2 Using a hex-head plastic

adjustment tool, adjust
the convergence control
on the CRT video board
for best overall
convergence.
Convergence
Control
Adjustments Convergence - 22

3 Using a hex-head plastic

adjustment tool, adjust
the N/S amp control for
best convergence of
N/S Amp
horizontal lines at the
Crosshatch I
Upper top and bottom of the
Correction screen.
Lower 4 Adjust the lower
Correction correction control for
best convergence of
vertical lines at the
bottom of the screen.

5 Adjust the upper

correction control for
best convergence of
vertical lines at the top
of the screen.
 Adjustments Geometric Distortion - 23

Geometric
Distortion
Before you begin, remove
the rear cover.

±Warning: This product

contains high voltage and a
high-vacuum picture tube.
To prevent serious injury,
review CRT safety in
Bulletins/Safety.

Adjustment WARNING:
Controls High Voltage Areas
Adjustments Geometric Distortion - 24

1 Use Display Service

Utility to display the
Crosshatch I test
pattern.

2 Verify that the boxes on

the top row are the same
size as the boxes on the
bottom row, and the
boxes on the left side are
the same size as the
boxes on the right side.

Crosshatch I
Adjustments Geometric Distortion - 25

±Warning: The entire yoke

assembly has very high
voltage. To prevent
electrical shock, do not
touch the yoke assembly, the
Horizontal Bow anode wire, or the yoke
wires.

3 To determine which
control to adjust,
Pin Phase compare the display with
the distortions shown.

4 Using a hex-head plastic

Vertical Angle adjustment tool, adjust
the control (see next
page for control
locations).
 Adjustments Geometric Distortion - 26

5 Using a hex-head plastic

adjustment tool, adjust
the control that is
appropriate for the
distortion.

6 If the display is so
distorted that you can’t
tell which adjustments
Analog to make, perform the
Board
adjustments in the
following sequence:
• Pin Phase (KS)
• Vertical Angle (PR)
• Horizontal Bow (PB)

7 If the display is still

distorted, repeat the
vertical angle and pin
Adjustments Geometric Distortion - 27

phase adjustments. If
you can’t correct the
distortion, replace the
analog board. See
“Analog Board” in the
Take Apart chapter.
Adjustments Yoke - 28

Yoke
Before you begin, remove
the rear cover.

Plastic Yoke Collar ±Warning: This product

contains high voltage and a
high-vacuum picture tube.
Yoke Clamp To prevent serious injury,
Screw
review CRT safety in
Bulletins/Safety.

WARNING:
High Voltage Areas
Adjustments Yoke - 29

±Warning: Because you

must make yoke adjustments
from the rear of the
computer, use a mirror to
view the computer screen.
Do not reach around the
computer to adjust collars
and rings.

Note: If you replace the

CRT, you will probably need
to adjust the yoke.
Adjustments Yoke - 30

1 Using an insulated
Phillips screwdriver,
loosen the yoke clamp
screw two or three
turns.

2 Switch on the computer.

Yoke Clamp 3 With one hand, grasp
Screw the plastic yoke collar
and rotate it until the top
and bottom edges of the
picture are parallel with
the top and bottom of the
bezel.
Adjustments Yoke - 31

4 Switch off and unplug the

Plastic Yoke Collar computer.

5 Discharge the CRT.

6 Hold the plastic yoke

collar in position and
carefully tighten the
yoke clamp screw so that
the collar cannot slip. Do
Yoke Clamp
Screw not overtighten the
screw.

7 Replace the rear cover

and switch on the
computer.
Adjustments Yoke - 32

8 Verify that the top and

bottom edges of the
picture are parallel with
the top and bottom of the
bezel.
Adjustments Light Meter Setup - 33

Light Meter Setup

This topic covers setup for
three light meter models:
R77, L-248, and 246.
Model R77 (Apple part
number 076-0310) is the
newest model available.

Model R77
The R77 light meter is
capable of reading luminance
from 10 to 1,000
footcandles (fc).

Before you begin, remove

the 10X multiplier plate
Adjustments Light Meter Setup - 34

from the lens.

Three scales are shown on

the light meter:
• 200-1000 fc
• 50-250 fc
• 10-50 fc

Because display screen

luminance typically ranges
from 10 to 50 fc, take
readings from the bottom
scale only.
Adjustments Light Meter Setup - 35

To measure a display
screen’s luminance,

1 Set the scale switch to

the bottom position (to
set up the 10-50 fc
scale).

2 Place the lens against the

middle of the screen and
read the bottom scale.

Note: When the light meter

is not in use, slide the scale
switch to its top position,
and store the meter in its
protective case.

Important: If you suspect the

light meter is giving false
Adjustments Light Meter Setup - 36

readings, verify the

readings with a known-good
light meter or photometer.
Also check the age of the R77
light meter by its four-digit
manufacturing date stamp
(such as 0398 for March
1998).

Caution: Dropping the

meter can permanently
damage its accuracy. A
shock-damaged meter might
read incorrectly or its
pointer may not drop to
zero.
 Adjustments Light Meter Setup - 37

Lens Model L-248

1 Press the red button on
the back of the light
Side Switch
meter. If the reading is
Read Button out of the red area,
replace the battery.

2 Move the side switch to

its upper position so that
the scale reads 10
through 18.

3 Uncover the lens of the

meter.

Red Area 4 Place the lens against the

middle of the screen and
Scale
press the read button to
read the scale.
Adjustments Light Meter Setup - 38

Model 246
1 Remove the metal slide,
Lens if installed, from the
top of the light meter.

2 Install the white lens

Swivel Head
with the red dot.

3 Rotate the swivel head

so the lens of the meter
Scale
faces the monitor.

4 Place the lens against the

middle of the screen and
read the scale.
K Service Source

Exploded View
Macintosh TV
Exploded View 1

Exploded View
Screw (5)

I/O Door Rear Housing

922-0884 922-0883
Screw

Rear Case Fan

Access Cover 922-1803

Rear Case
Access
Cover Shield

Rubber Feet

Internal
Microphone
Assembly
CRT
661-1666
Analog Board
661-0872 Front Bezel
Hard Drive 922-0881
Connector
Adapter Drive Bezel
922-1820 922-0882
Hard Drive
661-1750
Hard Drive
Carrier
922-1806
Screw (4)
Floppy Drive Floppy
Shield Drive
Logic Board 922-1808 661-0474
6ii61-1724

Screw (4)
Chassis Floppy
Harness Drive
Assembly Carrier
922-0767 922-1807
Floppy Drive
922-1824
Connector Adapter
CD 922-1823
Audio CD
Adapter Connector CD-ROM Drive
922-1822 Adapter 661-0023
922-1821 CD-ROM
Screw (4) Drive Carrier
922-0850