Motorola GP series Service Manual

Troubleshooting Flow Chart for Receiver (Models with PCB 8486686Z02) (Sheet 1 of 2) 3-3
3.0 Troubleshooting Flow Chart for Receiver (Models with PCB
8486686Z02) (Sheet 1 of 2)
Bad SINAD
Bad 20dB Quieting
No Recovered Audio
START
Audio at pin 8
of U301?
Check Controller
Yes
No
Spray or inject 1st IF 44.85
MHz into
XTAL Filter
Audio heard?
B
Yes
No
Check 2nd LO signal
44.395 MHz at C367
Signal
Present?
B
Yes
Voltages
ok?
Biasing ok?
Check circuitry
around U301.
Replace U301 if
defect
No
No
A
Yes
Check Q302 bias
circuitry for faults.
Rotate Freq. Knob
Replace Q302.
Go to B
Yes
No
Check voltages on
U301
Check circuitry
around Y300.
Replace Y300 if
defect

Motorola GP series Specifications

General

Operating Temperature	-30°C to +60°C
Frequency Range	136-174 MHz
Number of Channels	16
Channel Spacing	12.5 kHz / 25 kHz
Battery Life	8 hours (with standard battery)
Operating Voltage	7.5V DC
Ingress Protection	IP54
MIL-STD	810 C, D, E, F