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Motorola Gm328 Gm338 Gm398 Detailed 6804112j18 E Manual

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Page 161

Troubleshooting Flow Chart for 25W Transmitter 3-3
2.0 Troubleshooting Flow Chart for 25W Transmitter  (Sheet 1 of 3)
Current 
increase 
when 
keyed?
NO YES
START
Check if Pressure Pad closes S3440
Check Components between 
Q3441 and RF Output, 
Antenna Switch 
D3471,D3472,Q3472 
VR3471,Q3471>500mA & 4A
1V
Short TP3403 to 
Ground
NO
YES
Voltage at 
TP3402 
rises?Check PA StagesNO
YES
PCIC U3501 
Pin 14 9.3V 
DC?Check 9.3 V Regulator 
U0641
NO
YESPCIC U3501 
Pin 16 >4V 
DCReplace PCIC U3501
NO
YESTP3404...

Page 162

3-4 Troubleshooting Flow Chart for 25W Transmitter
2.1Troubleshooting 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 YESDC Voltage 
at U3501 
Pin 23 =0?
2-6DC Voltage 
at U3402-1 
Pin 1?
YESPin 2 Volt-
age 0.62 * 
Voltage at 
Pin 1?
If U3201 Pin 2 is high,  
replace PCIC
NOReplace U3401
YES NODC
Voltage at 
U3402-1 Pin 
3 = 8.8V?
Check S3440, 
R3442 and R3443
YESPin 3 Volt-
age 0.51 * 
Voltage at 
Pin 1?
NOReplace...

Page 163

Troubleshooting Flow Chart for 25W Transmitter 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 
replacing Q3441
YESRF Voltage 
Q3421 Gate...

Page 164

3-6Troubleshooting Flow Chart for Synthesizer
3.0 Troubleshooting Flow Chart for Synthesizer
+5V at 
U3201 Pins
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)
Sta rt
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 Pins 14 &
15 of U3201?
Check 
R3201
Check C3319Is U3201 pin 2  
>4.5 VDC in Tx...

Page 165

Troubleshooting Flow Chart for VCO3-7
4.0 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...

Page 166

3-8Troubleshooting Flow Chart for VCO
THIS PAGE INTENTIONALLY LEFT BLANK 

Page 167

4-1
Section 4
VHF PCBS/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...

Page 168

4-2Allocation of Schematics and Circuit Boards
THIS PAGE INTENTIONALLY LEFT BLANK 

Page 169

VHF 1-25W PCBs / Schematics / Parts Lists4-32.0 VHF 1-25W PCBs / Schematics / Parts Lists
VCO-REV-T3
PA-REV-T1FE-REV-T3 IF-REV-T4 FRAC-T4
CNTL-REV-T6
C0101C0102C0104 C0106
C0107
C0131C0132C0211
C0212
C0221C0222
C0223 C0224C0225
C0226
C0227
C0228 C0231
C0232
C 0233
C0234C0235 C0236C0237
C0241
C0242 C0243
C0244
C0245C0246 C0251
C0252
C0253C0261
C0262C0267
C0421
C0441
C 0442
C 0443
C 0445
C 0446
C 0447
C 0448
C 0449
C 0470
C 0471
C 0472
C 0473
C 0474
C 0476
C 0477
C 0478
C0482
C0483
C0484...

Page 170

4-4VHF 1-25W PCBs / Schematics / Parts Lists
C0103C0105
C0111 C0112C0121
C0122 C0123
C0141
C0151 C0201C0202
C0203
C0204 C0205
C0254C0255
C0265
C0266
C0271C0272
C0273C0274
C0275
C0276
C0277
C0301
C0302
C0303C0304
C0305 C0324C0325
C0331
C0341
C0342
C0343
C0344
C0351
C0352
C0353 C0354 C0422
C0423
C 0426
C 0427
C 0428
C 0429
C0430
C0431 C0485 C0491 C0492
C0497
C0499C0541C0554 C0558
C0559C0560C0575
C0576
C0591
C0592C0593
C0611
C0621C0622 C0641
C0644 C0645
C0661 C0662
C0663
C0671 C3000
C3001C3003...
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