230
Frequency Synthesizer Fault Finding
TM8100/TM8200 Service Manual
© Tait Electronics Limited
June 2006
9.9
VCXO and TCXO Outputs
Task 35 —
VCXO Output
If the 3V power supply is not faulty, check the VCXO output as follows:
1.
Use an oscilloscope probe to check the VCXO output at the
following position:
2.
If the signal is correct, go to
. If it is not, go to
3.
The VCXO circuitry under the
VCXO
BOT
can is faulty. Remove the
VCXO BOT
can.
4.
Locate and repair the fault in the VCXO (
Q501
,
Q503
,
XL501
and
associated components) (see
5.
Confirm the removal of the fault and go to
. If the repair
failed, replace the board and go to
C536
— probe the via next to C536 (see
). The signal
should be:
VCXO output at C536: sine wave of 1.1
±
0.2 V
pp
on 1.4
±
0.2 V DC
A4 band:
IC509, pin 4
— probe the via next to
R5044
(see
). The signal should be:
VCXO output at pin 4 of IC509: square wave of 1.5
±
0.2 V
pp
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...