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Level 3 Service Manual
VAG (approximately 1.4V)
is present on R920?
1. Connect a headset.
2. Place UUT into manual
test mode, then enter 430#
(change audio path), 36#
(initiate acoustic loopback),
4707# (set audio level)
Approximately 1V is
Check J504, U900 and
related components.
See Note 1
Figure 29. Headset Microphone Not Functioning
6881036B20
START
NO
YES
YES
present on C1025?
NO
MOTOROLA CONFIDENTIAL - PROPRIETARY
Check U900
See Note 1
1. Remove headset.
2. 2.7V is present on
R977?
YES
1. Connect headset.
2. Approximately 0.5V
is now present on R977?
NO
Check J504
See Note 1
November 20, 2000
NO
Check R976,CR901
See Note 1
Check R928 and
C927.
See Note 1
NO
YES
MIC signal is
present on C1025?
YES
Check U800 and
U900
See Note 1
Note 1: Check components for correct
orientation, cold solder joints, physical
damage, and functionallity.
Troubleshooting
000788-O
45
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Table of Contents
Troubleshooting
