238
Frequency Synthesizer Fault Finding
TM8100/TM8200 Service Manual
© Tait Electronics Limited
June 2006
4.
Replace all cans.
5.
Repeat
to confirm the removal of the fault. If the repair
failed, replace the board and go to
.
Task 42 —
CODEC 2 Circuitry
If the CCTM checks indicate a fault in the CODEC 2 circuitry or with the
digital signals to and from the circuitry, rectify the fault as follows:
1.
Most of the CODEC 2 circuitry is situated under the
CDC
TOP
can.
If not already done, remove the
CDC
TOP
can.
2.
Check the following digital signals at
IC205
(see
):
■
pin 10 :
DIG
CDC
2
LRCK
■
pin 12 :
DIG
CDC
2
SCLK
■
pin 8 :
CDC
2
DIG
SDTO
■
pin 9 :
DIG
CDC
2
SDTI
.
These signals to and from the digital board should all be active:
3.
If the digital signals are correct, the CODEC 2 circuitry is suspect;
go to
. If they are not, go to
.
4.
If any or all digital signals are missing, check the connections between
IC205
and the digital board (see
5.
If there are faults such as open circuits in the connections, repair the
circuitry and repeat
If the connections are not faulty, then the digital board is faulty.
Replace the board and go to
6.
The CODEC 2 circuitry comprises
IC205
and associated components
under the
CDC
TOP
can (see
) as well as
R246
under the
CDC BOT
can (see
). Locate the fault.
7.
Repair the circuitry. Note that, if the circuitry is functioning properly,
probing the
TP
501
test point
(see
) during power-up
will show a five-step staircase signal followed by a random nine-step
staircase signal — this is the expected power-up auto-calibration
sequence.
8.
Confirm the removal of the fault, and go to
. If the repair
failed, replace the board and go to
9.
Replace all cans.
10.
Repeat
to confirm the removal of the fault. If the repair
failed, replace the board and go to
digital signals: 3.3
±
0.3 V
Summary of Contents for TM8235
Page 1: ...TM8100 mobiles TM8200 mobiles Service Manual MMA 00005 04 Issue 4 June 2006...
Page 10: ...10 TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...
Page 62: ...62 Description TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...
Page 148: ...148 Disassembly and Reassembly TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...
Page 162: ...162 Servicing Procedures TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...
Page 178: ...178 Interface Fault Finding TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...
Page 258: ...258 Receiver Fault Finding TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...
Page 446: ...446 Spare Parts TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...
