
198
Frequency Synthesizer Fault Finding
TP9100 Service Manual
© Tait Electronics Limited
May 2005
Task 28 —
Check VCO
Check that the correct receive and transmit frequencies are synthesized.
The receive frequency is that of the VCO output
SYN
RX
LO
1
at the
RX
port
shown in
. The transmit frequency is that of the output
SYN
TX
LO
at the
TX
port.
1.
Enter the CCTM command
335 1
to set the transmit-receive switch
on (transmit mode).
2.
Using a frequency counter, proceed as follows to observe the transmit
frequency at the
TX
port (see
) before and after grounding
the junction between
C541
and
R547
(see
While holding the probe from the counter on the
TX
port, use a pair
of tweezers to momentarily ground the junction. The frequency
should change to:
The loop filter will hold its output steady at 13.3 V. This should result
in a frequency equal to the maximum given in
.
3.
If the maximum frequency measured in
is correct, go to
. If it is incorrect, go to
, but if no frequency at all is
detected, go to
4.
Enter the CCTM command
335 0
to set the transmit-receive switch
off (receive mode).
5.
Proceed as follows to observe the receive frequency at the
RX
port
before and after applying 3 V DC to the junction of
C541
and
R547
;
there is a convenient 3 V level at
R544
(see
):
While holding the probe on the
RX
port, use the tweezers to momen-
tarily apply 3 V DC to the junction; do not touch the board with your
hand, and do not allow the tweezers to touch any cans when you
remove them. The frequency should change to:
The loop filter will hold its output steady at about 0V. This should
result in a frequency equal to the minimum given in
.
6.
If the minimum frequency measured in
is correct, go to
. If it is incorrect, go to
. If no frequency is detected,
.
TX port: maximum VCO frequency (see
RX port: minimum VCO frequency (see
Содержание TP9100
Страница 1: ...TP9100 portables Service Manual MPA 00005 01 Issue 1 00 May 2005 ...
Страница 4: ...4 TP9100 Service Manual Tait Electronics Limited May 2005 ...
Страница 10: ...10 TP9100 Service Manual Tait Electronics Limited May 2005 ...
Страница 11: ...TP9100 Service Manual 11 Tait Electronics Limited May 2005 TP9100 portables Chapter 1 Description of the Radio ...
Страница 74: ...74 Circuit Descriptions TP9100 Service Manual Tait Electronics Limited May 2005 ...
Страница 75: ...TP9100 Service Manual 75 Tait Electronics Limited May 2005 TP9100 portables Chapter 2 Servicing the Radio ...
Страница 78: ...78 TP9100 Service Manual Tait Electronics Limited May 2005 ...
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 ...