
3-4
TROUBLESHOOTING CHARTS
2.1
Troubleshooting Flow Chart for 25W Transmitter (Sheet 2 of 3)
Check PA Stages
No or too low Power when keyed
Measure DC Voltage at Pin 2 & 3 of U4401
>6
YES
DC Voltage
at U4501
Pin 23 =0?
2-6
DC Voltage
at U4402-1
Pin 1?
YES
Pin 2
Voltage 0.62
* Voltage at
Pin 1?
If U4201 Pin 2 is high,
replace PCIC
NO
Replace U4401
YES
NO
DC
Voltage at
U4402-1 Pin
3 = 8.8V?
Check S4440,
R4442 and R4443
YES
Pin 3
Voltage 0.51
* Voltage at
Pin 1?
NO
Replace U4401
<2V
DC
Voltage at
U4402-2
Pin 7?
>6V
Check Components
between U4402-2 Pin7
and Q4421. Check
Resistive Network at
Pins 5 & 6 before
replacing Q4421
YES
DC
Voltage at
U4402-2 Pin 5
<8.8V?
Check Components
between U4402-2 Pin7
and Q4421. Check Resis-
tive Network at Pins 5 & 6
before replacing Q4421
NO
Check Q4422
NO
Check Final PA Stage
2-6V
<2V
Check Resistive
Network at Pins 2 & 3
of U4402-1 before
replacing U4401
Check Q4442 and
Resistive Network at
U4402-1 Pin 3
before replacing
U4401
Summary of Contents for 6864115B62-C
Page 1: ...Professional Radio GM Series Detailed Service Manual 6864115B62 C ...
Page 2: ...ii ...
Page 4: ...iv ...
Page 5: ...Professional Radio GM Series Service Maintainability Issue July 2007 ...
Page 8: ...ii ...
Page 22: ...2 10 MAINTENANCE ...
Page 25: ...Professional Radio GM Series Controlhead Service Information Issue July 2007 ...
Page 77: ...Professional Radio GM Series Controller Service Information Issue May 2007 ...
Page 100: ...2 2 TROUBLESHOOTING CHARTS ...
Page 104: ...3 4 Controller schematics parts list ...
Page 154: ...3 52 Controller T12 Schematic Diagrams ...
Page 155: ...Professional Radio GM Series VHF 136 174MHz Service Information Issue May 2007 ...
Page 164: ...1 6 MODEL CHART AND TECHNICAL SPECIFICATIONS ...
Page 176: ...2 12 THEORY OF OPERATION ...
Page 186: ...3 10 TROUBLESHOOTING CHARTS ...
Page 190: ...4 4 VHF PCB SCHEMATICS PARTS LISTS ...
Page 252: ...4 66 VHF 1 25W PCB 8471235L02 Schematics VHF 136 174 MHz IF ...
Page 256: ...4 70 VHF 1 25W PCB 8471235L02 Schematics ...
Page 257: ...Professional Radio GM Series UHF 403 470MHz Service Information Issue May 2007 ...
Page 266: ...1 6 MODEL CHART AND TECHNICAL SPECIFICATIONS ...
Page 366: ...2 12 THEORY OF OPERATION ...
Page 372: ...3 6 Low Band TROUBLESHOOTING CHARTS ...