Motorola SSETM 5000 service manual DC Supply Failure-Page

Troubleshooting Charts: DC Supply Failure 9-5

9.4DC 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)

Voltage	No
= B+?

Check

Continuity of

Fuse F901

on transceiver

No

Fuse OK?

Replace

Fuse

Yes

Check Voltage

at pin 1 of

Q501

Voltage	No
= B+?

Yes

Check Voltage

at pin 3 of

Q502

Yes

Check Battery

Connections for

Good Contact

Voltage		No	Replace Front
			Cover Housing
= B+?
			Assembly
	Yes

1

Check Voltage

at pin 2 of

Q502

Fixed?

Yes

End

Replace

Q501

Yes	Voltage	No
	= 0V?

No

Replace

Q502

MAEPF-27391-A

6881094C12-A November 11, 2004