192
Frequency Synthesizer Fault Finding
TM8100/TM8200 Service Manual
© Tait Electronics Limited
June 2006
9.3
Phase-locked Loop
Introduction
If there is no fault with the power supplies, check the critical output from,
and inputs to, the PLL:
■
: supply for charge pump
■
: reference frequency input
■
DIG
SYN
EN
line input
■
SYN
LOCK
line output.
The measurement points for diagnosing faults concerning the PLL inputs
and output are summarized in
.
Task 7 —
Supply for
Charge Pump
First check the supply for the charge pump of the PLL.
1.
Measure the supply for the charge pump at pin 16 of
IC503
(see
).
2.
If the voltage is correct, go to
. If it is not, go to
3.
Check the C-multiplier
Q512
(see
IC503
itself; if necessary, replace the transistor or IC.
4.
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 16 of IC503: 5.0
±
0.3 V DC
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...
