Motorola HT Series User Manual

8-42 Maintenance: 800 MHz Troubleshooting Charts
8.14.2 Troubleshooting Flow Chart for Receiver (for PCB No. 8480641Z02/
8480641Z03) (Sheet 1 of 2)
Bad SINAD
Bad 20dB Quieting
No Recovered Audio
START
Audio at
pin 27 of
U351?
Check Controller
Yes
No
Spray or inject 1st IF into XTAL
Filter
IF Freq: 109.65 MHz
Audio heard?
B
Yes
No
Check 2nd LO Control
Voltage at R365
VCO locked?
B
Yes
16.8 MHz
check at pin
21 of U351?
Activity
on U351
pin 19?
Check FGU
No
No
A
A
Yes
Check Q350 bias
circuitry for faults
Rotate Freq. Knob
Check controller
Before replacing U351, check
2nd VCO Q350. Check VCO O/P
level, C385, C387
Yes
No

Motorola HT Series Specifications

General

Battery Type	Li-Ion
Waterproof	IP54
Operating Temperature	-30°C to +60°C
Frequency Range	VHF: 136-174 MHz
Number of Channels	16