VX-261 VHF SM Ec128n90e
VX-261 VHF SM Ec128n90e
VX-261 VHF SM Ec128n90e
VHF FM Transceiver
©2016 Vertex Standard LMR, Inc.
VX-261 EC128N90E
Service Manual
Introduction
This manual provides the technical information necessary for servicing the VX-261 VHF FM
Transceiver.
Servicing this equipment requires expertise in handing surface-mount chip components. At-
tempts by non-qualified persons to service this equipment may result in permanent damage not
covered by the warranty, and may be illegal in some countries.
Two PCB layout diagrams are provided for each double-sided board in this transceiver. Each side
of the board is referred to by the type of the majority of components installed on that side (“Side
A” or “Side B”). In most cases one side has only chip components (surface-mount devices), and
the other has either a mixture of both chip and leaded components (trimmers, coils, electrolytic
capacitors, ICs, etc.), or leaded components only.
As described in the pages to follow, the advanced microprocessor design of the VX-261 Trans-
ceiver allows a complete alignment of this transceiver to be performed without opening the case
of the radio; all adjustments can be performed from the front panel, using the “Alignment Mode”
menu.
While we believe the information in this manual to be correct, Vertex Standard assumes no li-
ability for damage that may occur as a result of typographical or other errors that may be present.
Your cooperation in pointing out any inconsistencies in the technical information would be ap-
preciated.
Important Note
This transceiver is assembled using Pb (lead) free solder, based on the RoHS specification.
Only lead-free solder (Alloy Composition: Sn-3.0Ag-0.5Cu) should be used for repairs performed on this apparatus.
The solder stated above utilizes the alloy composition required for compliance with the lead-free specification, and
any solder with the above alloy composition may be used.
Contents
Specifications................................................................................................................................................................. 2
Exploded View & Miscellaneous Parts ....................................................................................................................... 4
Parts List ....................................................................................................................................................................... 5
Block Diagram .............................................................................................................................................................. 6
Circuit Description ....................................................................................................................................................... 7
Alignment ...................................................................................................................................................................... 9
Cloning ........................................................................................................................................................................ 16
Main Unit Circuit Diagram ....................................................................................................................................... 17
KNOB (VOL)
RA161270A
LATCH PLATE
RA1453400
KNOB (FREQ)
RA1612800
PTT KNOB ASSY VX-261/264
CB7131000
SHIELD CASE COVER (FET)
RA125020A
MAIN UNIT ASSY
CB6992000
RING NUT
RA157250A (x 2 pcs)
RUBBER BOOTS
RA1458000
SHEET (6x6)
RA037690B
MECHANICAL PARTS
KNOB (VOL) RA161270A
KNOB (FREQ) RA1612800
Unit
During alignment, you may select the value among
dBμV, μV (EMF or PD), or dBm by the “UNIT”
Action of the switches box.
When the transceiver is in the “Alignment mode,“ the ac-
tion of the SIDE-1, SIDE-2, and PTT keys are ignored.
All of the action is controlled by the PC.
Caution
Please never turn off the power supply during
alignment. If the power supply is turned off during
alignment, the alignment data will be corrupted.
When perform the RX Tune and SQL alignment,
the RF level shows this unit according to this set-
ting.
Frequency Oscilloscope
Counter
1. Turn both transceivers “off”. 6. Press the PTT switch on the Source transceiver. The
2. Remove the plastic cap and its two mounting screws LED indicator on the top of the transceiver will glow
from the MIC/SP jack on the right side of the trans- Red, and the data will be transferred.
ceiver. Do this for both transceivers. 7. If there is a problem during the cloning process, the
3. Connect the optional CT-27 cloning cable between the LED indicator on the top of the transceiver will blink
MIC/SP jacks of the two transceivers. Red; check your cable connections and battery volt-
4. Press and hold in the PTT and SIDE-1 switches (just age, and try again.
below the PTT switch) while turning the transceiver 8. If the data transfer is successful, the LED indicator on
“on” (the order of the switch-on operation does not the top of the transceiver will turn off. Turn both trans-
matter). When Clone mode is successfully activated in ceivers “off” and disconnect the CT-27 cable. You can
this step. then turn the transceivers back on, and begin normal
5. On the Destination transceiver, press the SIDE-1 operation.
switch. The LED indicator on the top of the transceiv- 9. Replace the plastic cap and its two mounting screws.
er will glow Green.