
TP9100 Service Manual
Receiver Fault Finding
259
© Tait Electronics Limited
May 2005
Task 8 —
Moderately Low
Sensitivity
Following the initial investigation in Task 7, check the circuitry as follows
when the sensitivity loss is moderate.
1.
Remove the
RX FE TOP
can and, if not already done, the
IF IQ BOT
can.
2.
Check the soldering of all the components of the front-end tuning
circuitry from
C400
to
T401
(see
and
3.
Check the 3 V supply voltage at
L404
; use the measurement point
shown in
4.
Also check the LNA bias conditions. First measure V
c
between the
collector of
Q401
and ground (see
5.
Secondly, check I
c
. To do so, unsolder and raise one terminal of
L404
(tombstone position) (see
), connect a multimeter
between this terminal and the pad for the terminal, and measure the
current.
6.
If the checks in
reveal no fault, go to
If there is a fault, repair it and go to
7.
Check the signal level at the output of LO1 and continue the fault
diagnosis as in
“Power Supply for FCL” on page 205
8.
Recalibrate the receiver using the calibration application.
9.
Confirm the removal of the fault and go to
. If the repair failed, go to
V
c
: 2.7±0.1V
I
c
: 10±1mA
Table 11.2 Front-end tuning voltages and corresponding DAC values
Frequency band
Tuning voltages at five different frequencies
FE TUNE0
FE TUNE1
FE TUNE2
FE TUNE3
FE TUNE4
B1 band
Frequency (MHz)
DAC value
Voltage (V)
135.9
15 ± 15
0.20 ± 0.20
145.1
88 ± 15
1.04 ± 0.18
155.1
138 ± 15
1.65 ± 0.18
164.1
174 ± 15
2.04 ± 0.18
174.1
210 ± 15
2.52 ± 0.18
H5 band
Frequency (MHz)
DAC value
Voltage (V)
399.9
15 ± 15
0.2 ± 0.2
417.1
44 ± 15
0.52 ± 0.18
435.1
102 ± 15
1.20 ± 0.18
452.1
153 ± 15
1.84 ± 0.18
470.1
191 ± 15
2.28 ± 0.18
H6 band
Frequency (MHz)
DAC value
Voltage (V)
449.9
64 ± 20
0.75 ± 0.24
470.1
115 ± 15
1.35 ± 0.18
490.1
156 ± 15
1.85 ± 0.18
510.1
191 ± 15
2.35 ± 0.18
530.1
217 ± 15
2.60 ± 0.18
Summary of Contents for TP9100
Page 1: ...TP9100 portables Service Manual MPA 00005 01 Issue 1 00 May 2005 ...
Page 4: ...4 TP9100 Service Manual Tait Electronics Limited May 2005 ...
Page 10: ...10 TP9100 Service Manual Tait Electronics Limited May 2005 ...
Page 74: ...74 Circuit Descriptions TP9100 Service Manual Tait Electronics Limited May 2005 ...
Page 78: ...78 TP9100 Service Manual Tait Electronics Limited May 2005 ...
Page 100: ...100 General Information TP9100 Service Manual Tait Electronics Limited May 2005 ...
Page 126: ...126 Disassembly and Reassembly TP9100 Service Manual Tait Electronics Limited May 2005 ...
Page 148: ...148 Interface Fault Finding TP9100 Service Manual Tait Electronics Limited May 2005 ...
Page 158: ...158 Power Supply Fault Finding TP9100 Service Manual Tait Electronics Limited May 2005 ...
Page 250: ...250 Transmitter Fault Finding TP9100 Service Manual Tait Electronics Limited May 2005 ...
Page 268: ...268 Receiver Fault Finding TP9100 Service Manual Tait Electronics Limited May 2005 ...
Page 294: ...294 Spare Parts TP9100 Service Manual Tait Electronics Limited May 2005 ...
Page 298: ...298 Antenna Identification Chart TP9100 Service Manual Tait Electronics Limited May 2005 ...