MOTOROLA CONFIDENTIAL - PROPRIETARY
6881036B20
November 20, 2000
37
Level 3 Service Manual
Troubleshooting
000780-O
Figure 21. Low Transmitter Power
1. Remove U300.
2. Place UUT into manual test mode,
then enter 9823# (change GSM/DCS
mode), 11062# (GSM ARFCN), 1215#
(TX level), and 310# (Pseudo-random TX).
3. PA_B+ signal modulated byDM_CS
(approximately 3V P-P@ 217 Hz) is
present on U300 Pin 13?
Check U390 and U200
See Note 1
Check Q370 Pin 1,
Pin 2, and Pin 3
See Note 1
Correct signal is
present on U390
Pin 7?
-5V is present on U903 Pin1?
No: check U903 and U904.
Yes: check Q370 and R103.
See Note 1
-5V is present on
Q370 Pin 1?
Negative bias (approximately
-3V P-P) is present on U300
Pin 2 and Pin 8?
1. DM_CS is present on Q381?
No: check U800.
See Note 1
2. Correct control signal is
present on Q380 Pin 4?
1. Replace U300.
2. Check for intermittent
fault
See Note 1
YES
YES
YES
YES
YES
NO
NO
NO
NO
NO
M
O
N
Is PA_B+ present on
Q380 Pin 5 and Pin 8?
No: replace Q380
Replace
Q381
In most cases, a reference board can be
used to compare signals.
Note 1: Check components for correct
orientation, cold solder joints, physical
damage, and functionallity.
Summary of Contents for 38C V100
Page 1: ...Level 3 Service Manual Model V100 GSM Technology Product Family 38C Personal Communicator ...
Page 2: ......
Page 73: ...V100 BOARD LAYOUT PAGE 1 2 ...
Page 74: ...V100 BOARD LAYOUT PAGE 2 2 ...
Page 77: ...V100 CONNECTOR SCHEMATICS ...
Page 78: ...V100 DISPLAY SCHEMATICS ...
Page 79: ...V100 FM SCHEMATICS ...
Page 81: ......
Page 83: ......