Motorola Mototrbo - 5.0 Troubleshooting Flow Chart for Rx VCO

Troubleshooting Flow Chart for Rx VCO 1-11
5.0 Troubleshooting Flow Chart for Rx VCO (Sheet 1 of 3)
No Receive Signal at C0468
Visual Check of Board Ok?
No
Correct Problem
Yes
Is 8.2V DC at L0301 & L0304?
Radio did not boot up properly or
check 9V3 regulator
No
No
Yes
Vbe ~ 0.62 VDC for Q0300 & Q0301?
Check
R0308, L0302, R0303, R0304,
R0305, R0318, R0319, R0314,
R0316, R0315
Yes
No
RF Signal present at C0315?
Check components between C0315
and C0321 for short or open
Is RF prescaler level at C0170 between
200-300mV
No
No
Yes
Yes
No
RF Signal present at R0313?
Check components between C0386
to C0170 and C0315 for any
short or open.
Change Q0301 if needed
Yes
No
Yes
Check 0V at TP0005?
No
Check 1.8V at TP0301?
Check any RF signal at C0321?
No
No
Check R0383=5V?
Yes
Change Q0380
Change U0300
Yes
Yes
Check Controller troubleshooting
flow chart
Check the radio is programmed for
Receive mode