372
CODEC and Audio Fault Finding
TM9100 Service Manual
© Tait Electronics Limited
August 2005
13.1
Power Supplies
Introduction
First check that a power supply is not the cause of the fault. Of these
supplies, the 3.3 V DC supply (
+3
V
3
) will already have been checked in
“Power Supply Fault Finding” on page 153
. The remaining supplies that
need to be checked are:
■
Task 1
: 9 V DC supply from 9V regulator (
+9
V
0
)
■
Task 2
: 3 V DC supply from 3V regulator (
+3
V
0
AN
)
■
Task 3
: 2.5 V DC supply from 2.5V regulator (
+2
V
5
CDC
)
Two other supplies used in the CODEC and audio circuitry are a 1.8V DC
supply (
+1
V
8
) from the digital board and the 13.8 V DC supply (
+13
V
8
BATT
)
from the power connector. Faults in these supplies are dealt with elsewhere.
Task 1 —
9V Power Supply
First check the 9V DC supply (
+9
V
0
), which is required by IC201.
1.
Remove the main-board assembly from the chassis.
2.
Remove the
CDC
BOT
can.
3.
Measure the voltage
+9
V
0
at pin 4 of IC201 (see
Figure 13.1
).
4.
If the voltage is correct, go to
Task 2
. If it is not, go to
Step 5
.
5.
The fault will be at IC201 (see
Figure 13.1
), since any fault with the
9 V regulator in the PSU module will already have been rectified.
Therefore, check the soldering of IC201. Repair any fault.
6.
Confirm the removal of the fault and go to
“Final Tasks” on
page 147
. If the repair failed or the fault could not be found, replace
the main-board assembly and go to
“Final Tasks” on page 147
.
Task 2 —
3V Power Supply
If the 9V supply is correct, check the 3V DC supply (
+3
V
0
AN
) next.
1.
Measure the voltage
+3
V
0
AN
at the
TP
601
test point
(see
Figure 13.1
).
2.
If the voltage is correct, go to
Task 3
. If it is not, go to
Step 3
.
3.
The 3V regulator IC603 is suspect (see
Figure 13.1
). Check the
regulator as described in
Task 3
of
“Power Supply Fault Finding” on
page 158
.
pin 4 of IC201: 9.0
±
0.3V DC
TP601 test point: 2.9
±
0.3V DC
Summary of Contents for TM9100
Page 1: ...TM9100 mobiles Service Manual MMA 00017 01 Issue 1 August 2005 ...
Page 4: ...4 TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 10: ...10 TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 22: ...22 Introduction TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 62: ...62 Description TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 96: ...96 TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 138: ...138 Disassembly and Reassembly TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 152: ...152 Servicing Procedures TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 168: ...168 Interface Fault Finding TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 244: ...244 Receiver Fault Finding TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 396: ...396 CODEC and Audio Fault Finding TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 420: ...420 Fault Finding of Control Head TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 426: ...426 Spare Parts TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 430: ...430 TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 444: ...444 TMAA04 05 Ignition Sense Kit TM9100 Service Manual Tait Electronics Limited August 2005 ...
Page 448: ...448 TMAA10 01 Desktop Microphone TM9100 Service Manual Tait Electronics Limited August 2005 ...