
June 1999
68P02945C75-A
4-3
GTX/GTX LTR/LTS 2000 Portable Radios Service Ma nual
Troubleshooting
Troubleshooting Charts
Is the
LEDÕs red light
on or not?
Inspect:
1) Front cover ßexible circuit
2)Voltage regulator
Is biasing of
Q400 OK?
Troubleshoot
Power Control
circuit
Is Power Out
of pin 4 at PA
OK
Is PA drive
OK?
Is control
voltage high
or low?
Troubleshooting Flow Chart
for Transmitter
Start
No
power
Is
current
OK?
Troubleshoot
VCO
1. Check coupler U111
2. Check PIN diodes
3. Check harmonic Þlter
Inspect/repair
TX output
network
NO
NO
LOW
HIGH
YES
NO
NO
YES
YES
YES
Is Tx B+
OK?
Replace PA
module
Replace
Q400
NO
Replace PA
module
YES
NO
YES