Tait TM8000 Series, Service Manual

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TM8100 Mobile Radio Service Manual Introduction 21
May 2004 © Tait Electronics Limited
1.2 Radio Body
Main, Digital and
Internal Options Boards
The radio body consists of a rectangular case — or chassis — with a lid.
The chassis houses a main board with the receiver and transmitter
circuitry, and a digital board with the microprocessor that controls the
radio. There are different main boards available covering different
frequency bands and with different RF performances; refer to the
product codes in
Figure 1.8 . The digital board is reflow-soldered to the
main board. There is space in the lid for an optional internal options
board. The essentials of the arrangement are illustrated in the block
diagram of
Figure 1.6 .
Main-board Assembly
The rear edge of the main board is attached to a heat-transfer block. The
block is in thermal contact with the rear of the case, where there are
cooling fins for heat dissipation. Heat from the output stage of the
transmitter is conducted via the heat-transfer block to the rear and
radiated from the cooling fins. (The lower surface of the case is ridged
to augment the dissipation of heat.) The RF, auxiliary and power
connectors are fixed to the rear of the main board. They project through
apertures in the heat-transfer block and the rear of the case. The main
board, digital board, and heat-transfer block constitute a separate unit
called the main-board assembly.
Internal Options Boards
Either Tait-designed or custom internal options boards may be fitted in
the radio body. Full details of the boards are given in the accessories
and 3DK manuals. Any internal options board that is fitted might or
might not include an external options connector. If included, the
connector will project through an aperture in the rear of the lid. If there
is no connector, the aperture is sealed with a bung.
Internal Connections
There are three sets of internal connections to the main board; these use
the following connectors:
■
factory connector
■
control-head connector
■
internal options connector
The factory connector is for Factory use only. The control-head
connector is on the front edge of the main board; it is used to connect a
control-head loom from the control head to the main board. The
internal options connector is required when an internal options board is
fitted; it is used to connect an options loom between the two board
s.