TM8100/TM8200 Service Manual
Frequency Synthesizer Fault Finding
195
© Tait Electronics Limited
June 2006
Task 9 —
DIG
SYN
EN
Line
If the supply for the charge pump and the reference frequency are correct,
check the
DIG
SYN
EN
line input.
1.
Check the
DIG
SYN
EN
line at pin 10 of
IC503
(see
).
Enter the CCTM command
334 0
to switch off the synthesizer, and
measure the voltage at pin 10.
2.
Enter the command
334 1
to switch on the synthesizer, and measure
the voltage again.
3.
are correct, go to
. If they are not, go to
4.
Remove
R104
(see
) and repeat the above measurements
as follows:
5.
Enter the CCTM command
334 0
to switch off the synthesizer, and
measure the voltage at the via between
R104
(see
) and
the digital board.
6.
Enter the CCTM command
334 1
to switch on the synthesizer, and
measure the voltage at the via between
R104
(see
) and
the digital board.
7.
are still not correct, the
digital board is faulty; replace the board and go to
. If the voltages are correct, go to
.
8.
There is a fault between the digital board and
IC503
. Locate the fault.
Check and resolder
R104
in position (see
continuity between pin 10 of IC503 (see
) and the digital
board via R104.
9.
If there is a fault, repair the circuit, confirm the removal of the fault,
and go to
. If the repair failed or no fault
could be found, replace the board and go to
pin 10 of IC503: 0 V DC (after entry of CCTM 334 0)
pin 10 of IC503: 2.5
±
0.3 V DC (after entry of CCTM 334 1)
via at R104: 0 V DC (after entry of CCTM 334 0)
via at R104: 3.3
±
0.3 V DC (after entry of CCTM 334 1)
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...