Motorola Gm Series Detailed 6864115b62 A Manual

Troubleshooting Flow Chart for 25W Transmitter (Sheet 1 of 3) 3-5
2.2Troubleshooting Flow Chart for 25W Transmitter (Sheet 3 of 3)
Check Final PA Stage
NO 0V
1-4VBias 2 DC 
Voltage at 
TP3406?
YESRF Voltage 
at TP3401 
>100mV?
YESRF Voltage 
U3401 Pin 6 
>3V?
Supply
Replace Q3441
Check FGU (U3301)
NOCheck Components 
between TP3401  & 
C3417
NO YESASFIC  
U0221 Pin 6 
1-4V DC?
Check Bias Tuning 
before replacing ASFIC 
U0221
Check Components 
between ASFIC and 
Q3441 before repla-
cing Q3441
YESRF...

3-6TROUBLESHOOTING CHARTS
3.0 Troubleshooting Flow Chart for 45W Transmitter (Sheet 1 of 2)
Current in-
crease when 
keyed?
NO YESSTART
No or too low Power when keyed
Check Components between 
Q3441 and RF Output, Antenna 
Switch D3471,D3472>500mA & 5A
1V
>1V 4V 
DCReplace PCIC
U3501
NO
YESTP3404  
9.1V DC
If U3201 Pin 3 is high,  
replace PCIC 
U3501,otherwise 
check controller and 
FGU
YES
NO
TP3403 
>0.5V DC?Replace PCIC U3501Check Forward & Reverse 
Power Sense Circuitry 
(D3451 & D3452)
Check...

Troubleshooting Flow Chart for 45W Transmitter (Sheet 1 of 2) 3-7
3.1Troubleshooting Flow Chart for Transmitter (Sheet 2 of 2) 
Pin 2 
Voltage 0.62 
* Voltage at 
Pin 1?
NO
YES Check PA Stages
No or too low Power when keyed
NOYES
Replace U3401 Pin 3 
Voltage 0.51 
* Voltage at 
Pin 1?
2-4VSupply
0V
Bias 1 DC 
Voltage at 
TP3406?
NO YES
PCIC U3501 
Pin 24 2-4V 
DC?
Check Bias Tuning be-
fore replacing 
PCIC U3501
Check Voltage at Pin 2 & 3 of U3401
Replace U3401
Replace Q3421
NO 0V
1-4VBias 2 DC 
Voltage...

3-8TROUBLESHOOTING CHARTS
4.0 Troubleshooting Flow Chart for Synthesizer
+5V at 
U3201 Pin’s
13 & 30? 5V
 at pin 6 of 
D3201
Is information
from µP U0101
correct?
Is U3201 
Pin 47
= 13VDC ?
Is U3301 Pin 19
4.5 VDC in TX?  
(at VCO section)
Start
Visual 
check of the 
Board OK?Correct
Problem
Check 5V
Regulator 
U3211
Is 16.8MHz
Signal at
U3201 Pin 
19?
Check
Y3261, Y3263  and 
associated Parts
Are signals
at Pin’s 14 &
15 of U3201?
Check 
R3201
Check C3319Is U3201 pin 2  
>4.5 VDC in Tx & 

Troubleshooting Flow Chart for VCO3-9
5.0 Troubleshooting Flow Chart for VCO
Are Q3301
Base at 0.7V 
Collector at 4.5V 
Emitter at 110mV
Are Q3304
Base at 2.4V 
Collector at 4.5V 
Emitter at 1.7VAre U3301 Pins
13 at 4.4V
15 at 1.1V
10 at 4.5V
16 at 1.9V
Low or no RF Signal
at TP3001
Visual check
of board
OK?
35mV DC at
U3301 Pin 19
NO
YES
at base of Q3301
NO
NO
NO
NONO YES
YES
YES
YESYESLow or no RF Signal
at input to PA5V DC at U3301
Pin 14&18 OK ?
4.8V DC at
U3301 Pin 19
Is RF available 
at TP3401
YES...

3-10TROUBLESHOOTING CHARTS 

Chapter 4
VHF PCB/SCHEMATICS/PARTS LISTS
1.0 Allocation of Schematics and Circuit Boards
1.1 Controller Circuits
The VHF circuits are contained on the printed circuit board (PCB) which also contains the Controller 
circuits. This Chapter shows the schematics for the VHF circuits only, refer to the Controller section 
for details of the related Controller circuits . The PCB component layouts and the Parts Lists in this 
Chapter show both the Controller and VHF circuit components. The VHF schematics and...

4-2VHF PCB/SCHEMATICS/PARTS LISTS
 
 
Table 4-3   VHF 1-25W Diagrams and Parts Lists
PCB : 8486172B07  Main Board Top Side
8486172B07  Main Board Bottom Side Page 4-23
Page 4-24
SCHEMATICS
Power Amplifier 1 - 25W
Voltage Controlled Oscillator
Receiver Front End
IF
FRACN
Page 4-15
Page 4-17
Page 4-18
Page 4-25
Page 4-26
Parts List:  8486172B07 Page 4-27
Controller version is T7
Table 4-4    VHF 1-25W Diagrams and Parts Lists
PCB : 8486172B08  Main Board Top Side
8486172B08  Main Board Bottom Side Page...

VHF 1-25W PCB 8486172B04 / Schematics4-32.0 VHF 1-25W PCB 8486172B04 / Schematics
C0101
C0102C0104 C0105
C0106
C0107 C0121
C0131 C0132C0211
C0212
C0221C0222
C 0223C0224C0225
C0226
C0227
C0231C0232
C0233
C0234C0235 C 0236C0237
C0241
C0242 C0243
C0244
C0245C0246 C0251
C0252
C 0253 C0255
C0261
C 0262C0267
C0421 C0441
C0442
C0443
C0444
C0445
C0446
C0447
C0448
C0449C0451
C0452
C0453
C0454
C0455
C0456
C0457
C0458
C0459
C0460
C0461
C0462
C0463
C0464
C0466
C0467
C0468 C0470
C0471
C0472
C0473
C0474
C0476
C0477...

4-4VHF 1-25W PCB 8486172B04 / Schematics
C0103 C0111 C0112C0122 C0123
C0125
C0141
C0151 C0201
C0203
C 0204 C0205
C0254C0265
C0266
C0271C0272
C0273C0274
C0275
C0276 C0277
C0301C0302
C0303C0304C0305 C0324C0325
C0341
C0342
C0343
C0344
C0351
C0352
C0353 C0354
C0401
C0402
C0403
C0406
C0407
C0408
C0409
C0410
C0411 C0422
C0423
C0426
C0427
C0428
C0429
C0430C0431
C0485C0491 C0492
C0497 C0498
C0499C0541C0554 C0558C0559
C0560
C0575
C0576 C0591
C0592C0593
C0611
C0621C0622 C0641
C0644 C0645
C0661 C0662
C0663
C0671...