Dc Supply Failure - Motorola ASTRO XTS 5000 Detailed Service Manual

Troubleshooting Charts: DC Supply Failure
5.4 DC Supply Failure—Page 1
NOTE: Since the failure of a critical voltage supply might cause the radio to automatically power
down, supply voltages should first be probed with a multimeter. If all the board voltages
are absent, then the voltage test point should be retested using a rising-edge-triggered
oscilloscope. If the voltage is still absent, then another voltage should be tested using the
oscilloscope. If that voltage is present, then the original voltage supply in question is
defective and requires investigation of associated circuitry.
Problem with
DC Distribution
Network
Check Voltage
at pin 5 of
Q501 (VOCON)
No
Voltage
= B+?
Yes
Check Voltage
at pin 1 of
Q501
No
Voltage
= B+?
Yes
1
6881094C31-C
Check
Continuity of
Fuse F901
on transceiver
Check Battery
Connections for
Good Contact
Check Voltage
at pin 3 of
Q502
Check Voltage
Yes
Replace
Q501
No
Replace
Fuse OK?
Yes
Replace Front
No
Voltage
Cover Housing
= B+?
Assembly
Yes
at pin 2 of
Q502
No
Voltage
= 0V?
Fuse
Yes
Fixed?
No
Replace
Q502
MAEPF-27391-A
October 14, 2003
5-5
End