260
Transmitter Fault Finding (40W/50W)
TM8100/TM8200 Service Manual
© Tait Electronics Limited
June 2006
Frequency Bands
Where test procedures or figures differ according to the frequency band of
the radio, the frequency band is given in brackets. The frequency band may
be referred to as either ‘VHF’ (very high frequency) or ‘UHF’ (ultra high
frequency) or identified by the frequency sub-band, such as ‘B1’ or ‘H7’.
For example:
A definition of frequency bands is given in
Some fault-diagnosis tasks require programming the radio with the lowest,
centre or highest frequency in the radio’s frequency band. The relevant
frequencies for the different bands are listed in
.
Emergency
Frequencies
The following frequency ranges are reserved worldwide for use as maritime
emergency frequencies or by distress beacons:
■
B1 band: 156.8MHz ± 375kHz
■
H5 band: 406.0 to 406.1MHz
Do not program the radio with any frequency in the above ranges.
Can Removal
There are five cans shielding the bulk of the transmitter circuitry:
■
PAD
TOP
■
PAF
TOP
■
DIRC
TOP
■
PIN
TOP
■
LPF
TOP
.
To remove any can, first remove the board from the chassis. In the case of
the
PAD
TOP
and
PAF
TOP
cans, first detach the heat-transfer block from the
main board. Secure the block again after removing the cans. Follow the
procedures given in
“Disassembly and Reassembly” on page 129
.
Can Replacement
Replace all cans that have been removed only after repairing the board.
An exception is the B1 band, however, where the
LPF TOP
can must be in
place if the transmitter is to operate correctly.
RF output power: > 60W (
VHF
), > 52W (
UHF
)
current: < 15A (
VHF
), < 12A (
UHF
)
Table 11.2
Lowest, centre and highest frequencies in MHz
Band
Lowest
frequency
Centre
frequency
Highest
frequency
B1
H5
H7
136
400
450
155
435
485
174
470
520
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...
