Motorola GP68, Service Manual

Page: 57 / 85

March, 1997 6881086C09-O
5-5
GP68 Portable Radios Service Manual Troubleshooting
Troubleshooting Charts
Troubleshooting Flow Chart
for Microcontroller
START
APPLY POWER TO RADIO AND
WAS GOOD OR BAD POWER-ON
YES
DONE
WAS GOOD POWER-ON BEEP
ARE ALERT TONES
ENABLED IN SPM
USE SPM TO ENABLE TONES
INVOKE FACTORY
RESET IN SPM
WAS GOOD POWER
ON BEEP PRESENT
MAIN RADIO BOARDS MUST BE
REPLACED
ARE TONES PRESENT
ON POWER UP AT
U402 PIN 23?
AUDIO PROBLEM, TROUBLE-
SHOOT AUDIO CKT
WITH POWER CONNECTED TO RADIO AND THE RADIO TURNED
ON CHECK THE FOLLOWING:
1) 5V AT PIN 32 OF U401. IF NONE CHECK U411.
2) WITH HIGH IMPEDANCE PROBE CHECK FOR 7.9488MHZ AT
PIN 7 AND 10 OF U401, IF NO SIGNAL CHECK/REPLACE
L401/Q401.
3) CHECK DC AT PIN 19 OF U401. IF < 4.5VDC CHECK U402
PIN 25 FOR 2.1 MHZ SIGNAL.
4) CHECK FOR TYPICAL VOLTAGES OF U401 AND U402
VOLTAGES.
BEEP PRESENT
TURN ON
PRESENT
DONE
DONE
DONE
YES
YES
YES
YES
YES
NO/DONÕT
KNOW
NO
NO
NO
NO
(RF & CONTROLLER)
NOTE: U401 is not replaceable. If U401 is damaged, the controller and
RF boards both need to be replaced.