MOTOROLA CONFIDENTIAL - PROPRIETARY
6881036B20
November 20, 2000
31
Level 3 Service Manual
Troubleshooting
Figure 15. Device Will Not Receive GSM Signals
1. Connect an RF signal generator
to EXT CONN
TP1
. Set generator
(or GSM BCCH
#62
) as follows:
Frequency:
947.4 MHz
Level:
-30 dBm
2. Place unit under test (UUT)
into manual test mode, then enter
the following key sequences:
9823#
(change GSM/DCS mode)
450062#
(GSM ARFCN)
Is fault GSM only?
NO
YES
RX_VCO
signal (1347.4
MHz) is present on
C2456
?
NO
YES
947.4 MHz signal present on
output of
FL400
?
NO
YES
See "Q" Figure 18.
"No Receive VCO".
Check (in order):
FL400
,
U150
,
and
U151
.
See Note 1
400 MHz signal present on
C460
?
NO
YES
400 MHz signal present at
C480
?
NO
YES
400 MHz signal present on
C481
?
NO
YES
Check (in order)
U200
and
U800
.
See Note 1
Correct signal present on
C405
?
NO
YES
RX275_GSM
signal present on
collector of
Q400
?
No: See "P" Figure 17. "No
Yes: Check
Q400
See Note 1
Correct signal present on
C453
?
YES
Check
FL401
.
See Note 1
Correct signal present on
C460
(400 MHz)?
YES
RX275
signal present on
Q450
Pin 1
and
RX275_GSM
on
L450
?
No: See "P" Figure 17. "No
Receiver Control Matrix"
Yes: Check
Q450
See Note 1
RX275
signal present
on
Q450 Pin 1
and
RX275_GSM
on
L450
?
No: See "P" Figure 17.
"No Receiver Control
Yes: Check
Q450
See Note 1
Check
FL457
.
See Note 1
Check
Q480
.
See Note 1
Check for
intermittent faults
then end.
Note 1: Check components for correct
orientation, cold solder joints, physical
damage, and functionallity.
START
NO
NO
In most cases, a reference board can be
used to compare signals.
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: ......