Motorola GM328

Troubleshooting Flow Chart for Transmitter 3-3
2.0 Troubleshooting Flow Chart for Transmitter
No
DC Voltage
@ Gate of
Q1401
No
Yes
START
No or Low
TX
DC Voltage
@Drains of
Q1402 &
Q1403
@ Cathode of
D1401 &
D1402
DC Voltage
Drains of Q1402 &
AC Voltages @
Q1403 both sine or
both distorted
Check 9T1 and
Diode Bias Circuit
Verify RF Continuity
to gates of
Q1402 & Q1403
Check circuitry
between Q1402 &
Q1403 and
Antenna Port
Check
MOSBIAS_1
Supply and
Feed Network
No
<<18V pp
Yes
No
Yes
< 1 A
No
Check
Q1401
Device
Yes
CURRENT
RF @
Junction
R1413 & R1414
DC Voltage
@ TP1402 &
TP1403
Ye s
Check
MOSBIAS_2
MOSBIAS_3
and Feed Networks
Check DC/AC
Gate Circuits
of Q1402 & Q1403
Check Supply Feed
and/or PowerControl
Circuits.
No
>18V pp
Check
U1401
Device
AC Voltage
@ Gate of
Q1401
Yes
DC Voltage
@ U1401
Yes
No
Power Out
> 1 A
Look for
short on
Supply Line
Check Pressure Pad
and/or
Switch Circuitry
Ye s
No
TX
Safefy
Switch