
TP9100 Service Manual
Frequency Synthesizer Fault Finding
203
© Tait Electronics Limited
May 2005
Task 32 —
Repair Switching
Network
If the transmit-receive switch is not functioning correctly, first check the
DIG
SYN
TR
SW
line to confirm that the digital circuitry is not the cause. If the
digital circuitry is not faulty, the switching network is suspect.
1.
Enter the CCTM command
335 0
to set the transmit-receive switch
off (receive mode). Measure the voltage at the end of the
DIG SYN TR SW
line at
R576
(see
).
2.
Enter the CCTM command
335 1
to set the transmit-receive switch
on (transmit mode). Again measure the voltage at
R576
.
3.
If the voltages measured in
and
are correct, go to
4.
Enter the CCTM command
335 0
and measure the voltage at the left
side of
R720
(see
5.
Enter the CCTM command
335 1
and again measure the voltage at
the left side of
R720
.
6.
If the voltages measured in
and
are correct, go to
. If they are not, the digital circuitry is faulty; replace the main
board and go to
.
7.
Check for continuity between
R576
(see
) and
R720
.
8.
If no fault is found, go to
. If a fault is found, repair the circuit,
confirm that the voltages are now correct, and go to
. If the repair failed, replace the main board and go to
.
9.
Check the circuitry for the transmit-receive and 3 V switches (based
on
Q515
and
Q510
) (see
10.
If a fault is found, repair the circuit, confirm that the voltages are now
correct, and go to
. If the repair failed or
the fault could not be found, replace the main board and go to
.
R576: 0V DC (after entry of CCTM 335 0)
R576: 3.0V DC (after entry of CCTM 335 1)
left side of R720: 3.3
±
0.3V DC (after entry of CCTM 335 0)
left side of R720: 0V DC (after entry of CCTM 335 1)
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 ...