Subject: TW-4100A - Repeater Stop Scan on the UHF Band
Date: December 17, 1987
During repeater cross band operation, the TW-4100A may not detect a UHF
signal while it is alternating between the two bands. This is due to the
electric field generated by the strong UHF receiving signal causing the
busy circuit to malfunction. The following modification will allow detection
of the UHF signal.
REQUIRED PARTS:
(1) RESISTOR 4.7K OHM, 1/8th WATT PART # RD14BB2B472J
(1) CAPACITOR, ELECTROLYTIC 4.7uF, 16V PART # CE04CWlC4R7M
(1) DIODE lS1555 PART # V11-0076-05
Remove the 4 screws securing the top cover.
Remove the 10 screws securing the bottom cover.
Carefully remove the top and bottom covers. Do not damage the speaker
cable attached to the bottom cover. Refer to FIGURE 1 for the next 3 steps.
Locate connector number 12 on the Composite unit (RX-TX) on the bottom
of the transceiver.
Carefully strip 1/8 inch of insulation from the wire attached to pin 2
connector 12 approxiamently 1/4 inch from the connector (do not break
the wire).
Solder the 3 components (listed above) between the wire and ground.
A good ground location is the can around TC2 and L8.
Assemble the transceiver by reversing steps 1 - 4.
