214
Frequency Synthesizer Fault Finding
TM8100/TM8200 Service Manual
© Tait Electronics Limited
June 2006
Task 24 —
Repair PLL feedback
If both the minimum and maximum transmit frequencies are correct, the
PLL feedback is suspect.
1.
Resolder
R542
in position (see
2.
Remove the
VCO
BOT
can.
3.
Replace the components
C570
,
R578
(see
IC503
(see
4.
Confirm that the fault in the radio has been removed. If it has, go to
. If it has not, replace the board and go to
Task 25 —
Repair Transmit
VCO
If either or both the minimum and maximum transmit frequencies are
incorrect, the transmit VCO circuitry is faulty.
1.
Remove the
VCO
TOP
can.
2.
Check the transmit VCO. The circuitry is based on
Q510
(see
3.
If a fault is found, repair it and go to
. If no fault is found, go
4.
Repeat the frequency measurements in
5.
If the frequencies are now correct, resolder
R542
in position
(see
), and go to
. If they are
still not correct, go to
6.
Resolder
R542
in position (see
). Replace the board and
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...