TM8100/TM8200 Service Manual
Frequency Synthesizer Fault Finding
213
© Tait Electronics Limited
November 2007
Task 18 —
Repair PLL feedback
If both the minimum and maximum receive frequencies are correct, the
PLL feedback is suspect.
1.
Resolder
R542
in position (see
Figure 9.11
).
2.
Remove the
VCO
BOT
can.
3.
Replace the components
C567
,
R574
(see
Figure 9.12
) and
IC503
(see
Figure 9.11
).
4.
Also check the second stage of the receive buffer amplifier based on
IC5100
(see
Figure 9.12
). Repair any fault.
5.
Confirm that the fault in the radio has been removed. If it has, go to
“Final Tasks” on page 163
. If it has not, replace the board and go to
“Final Tasks” on page 163
.
Task 19 —
Repair Receive VCO
If either or both the minimum and maximum receive frequencies are
incorrect, the receive VCO circuitry is faulty.
1.
For all bands except K5, remove the
VCO
TOP
can.
For the K5 band, remove the
VCO
BOT
can.
2.
Check the receive VCO. The circuitry is based on
Q504
(see
Figure 9.11
for all bands except K5 and
Figure 9.12
for the
K5 band
).
3.
If a fault is found, repair it and go to
Step 4
. If no fault is found, go
to
Step 6
.
4.
Repeat the frequency measurements in
Step 2
and
Step 4
of
Task 17
.
5.
If the frequencies are now correct, resolder
R542
in position
(see
Figure 9.11
), and go to
“Final Tasks” on page 163
. If they are
still not correct, go to
Step 6
.
6.
Resolder
R542
in position (see
Figure 9.11
). Replace the board and
go to
“Final Tasks” on page 163
.
Summary of Contents for TM8100 mobiles
Page 1: ...TM8100 mobiles TM8200 mobiles Service Manual MMA 00005 05 Issue 5 November 2007...
Page 10: ...10 TM8100 TM8200 Service Manual Tait Electronics Limited November 2007...
Page 12: ...12 TM8100 TM8200 Service Manual Tait Electronics Limited November 2007...
Page 20: ...20 Introduction TM8100 TM8200 Service Manual Tait Electronics Limited November 2007...
Page 64: ...64 Description TM8100 TM8200 Service Manual Tait Electronics Limited November 2007...
Page 106: ...106 TM8100 TM8200 Service Manual Tait Electronics Limited November 2007...
Page 134: ...134 General Information TM8100 TM8200 Service Manual Tait Electronics Limited November 2007...
Page 168: ...168 Servicing Procedures TM8100 TM8200 Service Manual Tait Electronics Limited November 2007...
Page 464: ...464 Spare Parts TM8100 TM8200 Service Manual Tait Electronics Limited November 2007...
