Tait TM8000 Series, Service Manual

Page: 131 / 244

TM8100 Mobile Radio Service Manual Disassembly and Re-assembly of Radio 131
May 2004 © Tait Electronics Limited
6.2 Disassembly of Control Head
Introduction
This subsection covers the disassembly of control heads with UI and the
replacement of a damaged part or assembly. There are two stages in the
disassembly procedure:
■
remove control-head board
■
replace damaged part or assembly
For the latter task the control-head board must be removed. To repair
the board, removal is unnecessary unless there is a need to gain access to
components on the underside or to replace the complete board. A
separate circuit board for a concealed or dynamic microphone might or
might not be mounted on the control-head board.
Remove Control-head
Board
The procedure for removing the control-head board is as follows. Refer
to
Figure 6.3 .
1. Pull off the knob from the volume-control potentiometer. Do not
use any tools to do so as this might cause damage.
2. If a circuit board for a concealed or dynamic microphone is fitted,
unplug it from the control-head board.
3. If a concealed microphone is fitted, unsolder the microphone leads
from the control-head board. The leads are soldered to pads on
the board as shown in
Figure 6.3 .
4. Note whether the speaker leads are connected to the control-head
board. If so, disconnect the leads. The radio will need to be
returned to the Customer in its original state.
5. Use a Torx T10 screwdriver to remove the screws securing the
control-head board. The order of removal is immaterial. The
screws are labelled screw 1 to screw 3 in
Figure 6.3 ; these numbers
are also inscribed on the PCB. The control-head board is now
held down only by the clips labelled clip 1 to clip 3 in
Figure 6.3 .
6. Pull upwards on the edge of the control-head board adjacent to
the speaker. At the same time push clip 1 and clip 2 by hand away
from the board. The board will lift up slightly.
7. Push clip 3 away from the control-head board while
simultaneously pressing on the shaft of the volume-control
potentiometer. The board will be freed from the space-frame.
Remove the board.
8. If the earlier inspections have not revealed any damaged parts,
continue with the repair of the radio as described in
Subsection 5.2 (on page 109) . If there is damage, continue with
the disassembly of the control head and rectify the damage as
described below.