
TP9100 Service Manual
Frequency Synthesizer Fault Finding
179
© Tait Electronics Limited
May 2005
Task 12 —
VCO Faulty
If the loop voltage is correct, the loop filter is functioning properly.
The VCO and related circuitry is therefore suspect. The section to proceed
to depends on the type of the radio and the nature of the fault.
1.
. With a VHF radio go to
Related Circuitry (VHF Radios)” on page 196
2.
If a UHF radio exhibits a lock error or a receive fault. the receive
VCO is suspect; go to
“Receive VCO and Related Circuitry (UHF
.
If it exhibits a system error or a transmit fault, the transmit VCO is
suspect; go to
“Transmit VCO and Related Circuitry (UHF
.
Task 13 —
Check Reference
Voltage
If the loop-filter circuitry is suspect, first check the reference voltage for the
filter.
1.
Remove the
SYN BOT
can.
2.
Measure the reference voltage at pin 5 of
IC505
(see
).
The result should be:
3.
If the voltage is correct, go to
. If it is not, the reference-
voltage circuitry is suspect; go to
4.
Check
R5017
(see
5.
If a fault is found, repair the circuit, and confirm that the reference
voltage is now correct. If it is, go to
. If it
is not, or if no fault could be found, replace the main board, and go
to
.
IC505 pin 5:
2.5
±
0.05V 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 ...