Motorola Mototrbo - 6.0 Troubleshooting Flow Chart for Tx VCO

1-14 Troubleshooting Flow Chart for Tx VCO
6.0 Troubleshooting Flow Chart for Tx VCO (Sheet 1 of 3)
No Transmit Signal at C0703
Visual Check of Board Ok?
No
Correct Problem
Yes
Is 8.2V DC at L0301 & L0304?
Radio did not boot up properly or
Change U0300
check 9V3 regulator
No
No
Yes
Vbe ~ 0.62 VDC for Q0300 & Q0301?
Check R0306, R0308, L0302, R0303,
R0304, R0305, R0318, R0319,
R0314, R0316, R0315
Yes
No
RF Signal present at C0315?
Check components between C0315
and C0321 for any 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
Yes
Yes
Check 1.8V at TP0005?
No
Check 5V at
TP0300?
Check 0V at
C0385?
No No
Check R0383, Q0380 and
change if needed
Yes
Check any RF
signal at C0321?
Yes
Check Q0381, R0384, C0384 and
change if needed
Check the radio is programmed for
Receive mode