Motorola HT Series Detailed Service Manual page 136

8-46
8.14.6 Troubleshooting Flow Chart for Transmitter (for PCB No. 8480641Z02/
8480641Z03)
Replace F501
No
Replace
Q101
No
Replace
U101
Low Power
No
Is the fuse
F501 OK?
Is the voltage
at R105 and
C116 between
1.8V and
2.2V?
Yes
Is the voltage
at pins 6, 5, 8, 9 of
U101 between 5.5V
and 7.5V?
Yes
Troubleshoot
VCO
Maintenance: 800 MHz Troubleshooting Charts
START
No Power
No Power out or Low
Power
No
Check L101, L102, C101,
CR101 for open circuit
Yes
Is the voltage
at pin 4 of
U102
between 2V
and 5.6V?
Yes
Is the voltage
at pin 32 of
U102 between
6V and 9V?
Yes
Is the
voltage at pin 24
of U102 between
2V and 5V for High
Power, 0V for
Low Power?
Yes
Is overall
radio current
Yes
between 0.8
and 1.3 A
when
transmitting?
No
Is there a
short circuit
after C113?
No
Replace
Find and remove
U102
short circuit from
antenna switch or
harmonic filter
No
No
Yes