
TP9100 Service Manual
CODEC and Audio Fault Finding
285
© Tait Electronics Limited
May 2005
Task 12 —
Initial Checks of the
External (Accessory)
Microphone
Carry out the following checks to isolate the part of the circuitry that is
faulty.
1.
Check the connector
PL1
(see
) and the flexible acces-
sory board connection to the main board as defined in
. Assuming this is correct, proceed to
2.
Check the DC level on the
ACC MIC
signal on pin 6 of
PL1
.
3.
If the DC level is not present check and repair components and
soldering around
PL1
,
E901
, and
C910
(see
). If the
signal is present, the audio path is suspect; go to
.
4.
Confirm the removal of the fault and go to
. If the repair failed, the DC bias is suspect; go to
Task 13 —
Check External
(Accessory)
Microphone Audio
To check the modulation from the external microphone:
1.
Apply an AC-coupled 1 kHz audio signal with level 9.5mV
rms
to the
ACC MIC
signal on pin 6 of the connector PL1.
2.
Check that the audio signal appears at the junction of
R229
,
R232
,
and
C213
(see
):
3.
If the signal is not present, check and repair components and
soldering around
R229
,
R232
, and
C213
(see
). If the
signal is present go to
“Frequency Synthesizer Fault Finding” on
4.
Confirm the removal of the fault and go to
. If the repair failed or the fault could not be found, replace
pin 6 of PL1: 3.0 ±0.3V (typical)
junction of R229, R232, and C213: 9.5mV
rms
with 1.5V DC offset
Summary of Contents for TP9100
Page 1: ...TP9100 portables Service Manual MPA 00005 01 Issue 1 00 May 2005 ...
Page 4: ...4 TP9100 Service Manual Tait Electronics Limited May 2005 ...
Page 10: ...10 TP9100 Service Manual Tait Electronics Limited May 2005 ...
Page 74: ...74 Circuit Descriptions TP9100 Service Manual Tait Electronics Limited May 2005 ...
Page 78: ...78 TP9100 Service Manual Tait Electronics Limited May 2005 ...
Page 100: ...100 General Information TP9100 Service Manual Tait Electronics Limited May 2005 ...
Page 126: ...126 Disassembly and Reassembly TP9100 Service Manual Tait Electronics Limited May 2005 ...
Page 148: ...148 Interface Fault Finding TP9100 Service Manual Tait Electronics Limited May 2005 ...
Page 158: ...158 Power Supply Fault Finding TP9100 Service Manual Tait Electronics Limited May 2005 ...
Page 250: ...250 Transmitter Fault Finding TP9100 Service Manual Tait Electronics Limited May 2005 ...
Page 268: ...268 Receiver Fault Finding TP9100 Service Manual Tait Electronics Limited May 2005 ...
Page 294: ...294 Spare Parts TP9100 Service Manual Tait Electronics Limited May 2005 ...
Page 298: ...298 Antenna Identification Chart TP9100 Service Manual Tait Electronics Limited May 2005 ...