258
Receiver Fault Finding
TM8100/TM8200 Service Manual
© Tait Electronics Limited
November 2007
6.
Check the signal level at the output of LO1 and continue the fault
diagnosis as in
“Power Supply for FCL” on page 234
.
7.
Confirm the removal of the fault and go to
“Final Tasks” on page 163
on page 136
. If the repair failed, go to
Task 9
.
Task 9 —
Slightly Low
Sensitivity
Following the initial investigation in
Task 7
, check the circuitry as follows
when the sensitivity loss is slight.
1.
Remove the
FE
TOP
can and, if not already done, the
IF
TOP
can.
2.
Check the soldering of all the components of the front-end tuning
circuitry from
C400
to
T401
(see
Figure 10.1
and
Figure 10.3
).
3.
Check the IF-amplifier bias conditions as in
Step 4
and
Step 5
of
Task 5
.
4.
Check the LNA bias conditions as in
Step 4
and
Step 5
of
Task 8
.
5.
If the checks of
Step 2
to
Step 4
reveal no fault, go to
Step 6
. If there
is a fault, repair it and go to
Step 7
.
6.
Check the PIN switch and LPF as in Task 31 to Task 33 of
“Transmitter Fault Finding (>25W)” on page 267
or
“Transmitter
Fault Finding (25W)” on page 341
.
7.
Recalibrate the receiver using the calibration application.
8.
Confirm the removal of the fault and go to
“Final Tasks” on
page 163
. If the repair failed, replace the board and go to
“Final
Tasks” on page 163
.
Table 10.3
Front-end tuning voltages and corresponding DAC values (K5 band)
Frequency band
Tuning voltages at five different frequencies
FE TUNE0
FE TUNE1
FE TUNE2
FE TUNE3
FE TUNE4
K5 band
Frequency (MHz)
DAC value
Voltage (V)
761.9
0
0
776.1
0
0
849.9
255
3.0
860.1
255
3.0
870.1
255
3.0
Содержание TM8100 mobiles
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Страница 10: ...10 TM8100 TM8200 Service Manual Tait Electronics Limited November 2007...
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Страница 20: ...20 Introduction TM8100 TM8200 Service Manual Tait Electronics Limited November 2007...
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Страница 134: ...134 General Information TM8100 TM8200 Service Manual Tait Electronics Limited November 2007...
Страница 168: ...168 Servicing Procedures TM8100 TM8200 Service Manual Tait Electronics Limited November 2007...
Страница 184: ...184 Interface Fault Finding TM8100 TM8200 Service Manual Tait Electronics Limited November 2007...
Страница 246: ...246 Frequency Synthesizer Fault Finding TM8100 TM8200 Service Manual Tait Electronics Limited November 2007...
Страница 340: ...340 Transmitter Fault Finding 25W TM8100 TM8200 Service Manual Tait Electronics Limited November 2007...
Страница 398: ...398 Transmitter Fault Finding 25W TM8100 TM8200 Service Manual Tait Electronics Limited November 2007...
Страница 422: ...422 CODEC and Audio Fault Finding TM8100 TM8200 Service Manual Tait Electronics Limited November 2007...
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