
188
Frequency Synthesizer Fault Finding
TP9100 Service Manual
© Tait Electronics Limited
May 2005
Task 19 —
Repair Receive VCO
If either or both the minimum and maximum receive frequencies are
incorrect, the receive VCO circuitry is faulty.
1.
Remove the
VCO TOP
can.
2.
Check the receive VCO. The circuitry is based on
Q504
(see
3.
If a fault is found, repair it and go to
. If no fault is found, go
4.
Repeat the frequency measurements in
and
5.
If the frequencies are now correct, resolder
R542
in position
(see
), and go to
. If they are
still not correct, go to
6.
Resolder
R542
in position (see
). Replace the main
board and go to
Task 20 —
Check Switching
to Receive Mode
If no receive frequency is detected in the check of the receive VCO, first
check that the transmit-receive switch is functioning correctly.
1.
Resolder
R542
in position (see
2.
Enter the CCTM command
335 0
to switch on the supply to the
receive VCO.
3.
Measure the voltage at the first collector (pin 3) of
Q506
(see
). The voltage should be:
4.
Enter the CCTM command
335 1
to switch off the supply.
5.
Again measure the voltage at the first collector of
Q506
.
6.
If the voltages measured in
are correct, go to
. If they are not, the switching network is suspect; go to
.
pin 3 of Q506: 5.0
±
0.3V DC (after entry of CCTM 335 0)
pin 3 of Q506: 0V DC (after entry of CCTM 335 1)
Содержание TP9100
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Страница 74: ...74 Circuit Descriptions TP9100 Service Manual Tait Electronics Limited May 2005 ...
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Страница 100: ...100 General Information TP9100 Service Manual Tait Electronics Limited May 2005 ...
Страница 126: ...126 Disassembly and Reassembly TP9100 Service Manual Tait Electronics Limited May 2005 ...
Страница 148: ...148 Interface Fault Finding TP9100 Service Manual Tait Electronics Limited May 2005 ...
Страница 158: ...158 Power Supply Fault Finding TP9100 Service Manual Tait Electronics Limited May 2005 ...
Страница 250: ...250 Transmitter Fault Finding TP9100 Service Manual Tait Electronics Limited May 2005 ...
Страница 268: ...268 Receiver Fault Finding TP9100 Service Manual Tait Electronics Limited May 2005 ...
Страница 292: ...292 Spare Parts TP9100 Service Manual Tait Electronics Limited May 2005 Figure 13 1 Serviceable parts 3 3 3 4 4 3 4 ...
Страница 294: ...294 Spare Parts TP9100 Service Manual Tait Electronics Limited May 2005 ...
Страница 295: ...TP9100 Service Manual 295 Tait Electronics Limited May 2005 TP9100 portables Chapter 3 Accessories ...
Страница 298: ...298 Antenna Identification Chart TP9100 Service Manual Tait Electronics Limited May 2005 ...
Страница 306: ...306 TPA CH 001 Single Battery Charger TP9100 Service Manual Tait Electronics Limited May 2005 15 6 5 Circuit Diagram ...