TM8100/TM8200 Service Manual
Frequency Synthesizer Fault Finding
217
© Tait Electronics Limited
June 2006
9.7
VCO and Related Circuitry (VHF Radios)
Introduction
If there is no fault with the power supplies, the PLL inputs and output, and
the loop filter, check the VCO and related circuitry. The procedures in this
section apply only to VHF radios; the VHF frequency bands are defined in
. There are six aspects:
■
: check VCO
■
: repair PLL feedback
■
: repair VCO
■
: check transmit-receive switch
■
: repair switching network
■
: check buffer amplifier.
The measurement points for diagnosing faults in the VCO and related
circuitry are summarized in
Table 9.5
Minimum and maximum frequencies for the different VHF frequency bands
Frequency band
Frequency in MHz
Minimum
Maximum
A4
55
±
5
125
±
5
B1
84
±
5
200
±
5
C0
137
±
5
247
±
5
D1
167
±
5
287
±
5
Summary of Contents for TM8235
Page 1: ...TM8100 mobiles TM8200 mobiles Service Manual MMA 00005 04 Issue 4 June 2006...
Page 10: ...10 TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...
Page 62: ...62 Description TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...
Page 148: ...148 Disassembly and Reassembly TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...
Page 162: ...162 Servicing Procedures TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...
Page 178: ...178 Interface Fault Finding TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...
Page 258: ...258 Receiver Fault Finding TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...
Page 446: ...446 Spare Parts TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...