TM8100/TM8200 Service Manual
Frequency Synthesizer Fault Finding
201
© Tait Electronics Limited
June 2006
Task 15 —
Check
DIG
SYN
FAST
Line
If the loop filter is suspect but the reference and feedback voltages are
correct, check the
DIG
SYN
FAST
line, which is input to the inverter.
1.
Enter the CCTM command
389 1
to set the synthesizer mode to fast.
2.
Measure the voltage at the collector of
Q505
(see
The result should be:
3.
Enter the CCTM command
389 0
to set the mode to slow.
4.
Measure the voltage at the collector of
Q505
(see
The result should be:
5.
are correct, go to
. If they are not, go to
6.
Remove
R105
(see
).
7.
Enter the CCTM command
389 1
to set the mode to fast.
8.
Measure the voltage at the via between
R105
and the digital board
(see
). The result should be:
9.
Enter the CCTM command
389 0
to set the mode to slow.
10.
Measure the voltage at the via between
R105
and the digital board
(see
). The result should be:
11.
If the voltages measured in
are correct, go to
. If they are not, the digital board is faulty; replace the board
and go to
12.
Check and resolder
R105
in position (see
continuity between the collector of
Q505
(see
digital board via R105.
13.
If a fault is found, repair the circuit, and confirm that the voltages are
now correct. If they are, go to
. If they are
not, or if no fault could be found, replace the board and go to
.
Q505 collector: 14.2
±
0.3 V DC (after entry of CCTM 389 1)
Q505 collector: 0 V DC (after entry of CCTM 389 0)
via at R105: 0 V DC (after entry of CCTM 389 1)
via at R105: 3.3
±
0.3 V DC (after entry of CCTM 389 0)
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...
