Tait TM8100 mobiles, Service Manual

Page: 26 / 620

26 Description TM8100/TM8200 Service Manual
© Tait Electronics Limited November 2007
The main board
1^
is attached to the heat-transfer block
H
with three
M3x10 Torx-head screws
B
and the fastening elements
J
,
1#
and
1$
of the
auxiliary and RF connectors.
The inner foam D-range seal
G
seals the auxiliary connector against the
heat-transfer block. The power connector seal
1)
seals the power connector
against the heat-transfer block.
The power connector seal
1)
of the >25W radio (blue) is different to the
seal of the 25W radio (black).
Main Board
The main board
1^
is a printed circuit board in SMT design with
components on the top and bottom sides. A digital board
D
is reflow-
soldered to the main board. Most components are shielded by metal cans.
There are different main boards for each frequency band and each RF
output power configuration.
The internal options connector
E
for connecting an internal options board
and the factory connector (not illustrated) for factory use are soldered to the
top side of the main board. The control-head connector
1&
(facing the front
of the radio) and the auxiliary
F
, power
1!
and RF
1%
connectors (facing
the rear of the radio) are located on the bottom side of the main board.
The >25W radio has a black power connector
1!
and the 25W radio has a
white power connector.
For more information on the connectors, refer to “Connectors” on
page 38 .
For heat dissipation, one of the screw bosses inside the chassis is in contact
with the underside of the main board. A larger copper plate at the underside
of the main board connects to the body of the heat-transfer block.
The >25W radio has an additional gap pad between the heat-transfer block
and the main board
1^
which connects to an additional copper plate at the
bottom side of the main board.
Heat-Transfer Block
The aluminium heat-transfer block
H
dissipates heat from the main board
to the heat fins of the chassis. The heat-transfer block has a contact surface
to the larger copper plate at the underside of the main board
1^
, and a
contact surface to the rear of the chassis. All contact surfaces are coated with
thermal paste.
Two self-adhesive foam seals
G
and
I
around the aperture of the auxiliary
connector on either side of the heat-transfer block and the power connector
seal
1)
inside the aperture of the power connector are fitted to the heat-
transfer block.
25W >25W
25W >25W
>25W