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 U3401
>6
YES
DC Voltage
at U3501
Pin 23 =0?
2-6
DC Voltage
at U3402-1
Pin 1?
YES
Pin 2 Volt-
age 0.62 *
Voltage at
Pin 1?
If U3201 Pin 2 is high,
replace PCIC
NO
Replace U3401
YES
NO
DC
Voltage at
U3402-1 Pin
3 = 8.8V?
Check S3440,
R3442 and R3443
YES
Pin 3 Volt-
age 0.51 *
Voltage at
Pin 1?
NO
Replace U3401
<2V
DC Voltage
at U3402-2
Pin 7?
>6V
Check Components
between U3402-2 Pin7
and Q3421. Check
Resistive Network at
Pins 5 & 6 before
replacing Q3421
YES
DC Voltage
at U3402-2
Pin 5 <8.8V?
Check Components
between U3402-2 Pin7
and Q3421. Check
Resistive Network at Pins
5 & 6 before replacing
Q3421
NO
Check Q3422
NO
Check Final PA Stage
2-6V
<2V
Check Resistive Net-
work at Pins 2 & 3 of
U3402-1 before replac-
ing U3401
Check Q3442 and
Resistive Network at
U3402-1 Pin 3
before replacing
U3401
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 ...