Motorola SSETM 5000 service manual VHF U1

Troubleshooting Charts: DC Supply Failure 9-7

DC Supply Failure—Page 3

3

Check Voltage

at pin 5 of

U505 (VOCON)

	Voltage		No	Check R503,
	= 5.0V+/-5%?			D501, C509,
				C510, and C508
		Yes
	Check Voltage
	at TP5
		* per Standard Bias Table
				Check
	Voltage		No	700-800: E6, C15,
	= V2?*			C16, C17, and D2
				VHF: E6, C6,
				C8, and D2
		Yes
	Check Voltage
	at TP7
		* per Standard Bias Table
				Check
	Voltage		No	700-800: D3, R704,
	= V2?*			C19, and C20
				VHF: E7, C9, C10,
				C11, and D3
		Yes
No	Is unit
	VHF?

Yes

Check Voltage

at TP6

* per Standard Bias Table

Components No OK?

Yes

Replace

700-800: U505

VHF: U1

Components No OK?

Yes

Replace

U2

Components No OK?

Yes

Replace

U3

Replace

Problem

Component

Replace

Problem

Component

Replace

Problem

Component

Voltage		No	Check	Components		No
= V2?*			E8, C18, C19,
			C20, and D4	OK?
	Yes				Yes
Check Voltage				Replace
at TP3				U5
			Check
Voltage		No	700-800: D1, E5,	Components		No
			C12, C13, and C14
= 5.0V+/-5%?
			VHF: E5, C3, C4,	OK?
			C5, and D1
	Yes				Yes
End				Replace
				U1

Replace

Problem

Component

Replace

Problem

Component

MAEPF-27393-C

6881094C12-A November 11, 2004