
168
Frequency Synthesizer Fault Finding
TP9100 Service Manual
© Tait Electronics Limited
May 2005
Task 5 —
4.3V Power Supply
If the SMPS output and 5V DC supply are correct, check the
+4
V
3
DEC
supply next.
1.
Remove the
SYN TOP
can.
2.
Measure the supply
+4
V
3
DEC
at pin 4 of
Q508
(see
).
3.
If the voltage is correct, go to
. If it is not, go to
(UHF
radios) or
(VHF radios).
4.
With a UHF radio check for faults in the C-multiplier
Q508
(pins 3,
4, 5) and the 5V and transmit-receive switches based on
Q513
,
Q507
and
Q508
(pins 1, 2, 6) (see
). Replace any suspect
transistor. Conclude with
5.
With a VHF radio check for faults in the C-multiplier and 5 V switch
based on
Q508
and
Q513
(see
). Check the operation of
Q517 and Q513. Conclude with
.
6.
If a fault is found, repair the circuit, confirm the removal of the fault,
and go to
. If the repair failed or no fault
could be found, replace the main board, and go to
pin 4 of Q508: 4.3
±
0.15V DC
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 ...