Tait TM8100 mobiles, Service Manual

Page: 454 / 620

454 Fault Finding of Control Head with 1-, 2- or 3-Digit Display TM8100/TM8200 Service Manual
© Tait Electronics Limited November 2007
15.7 Speaker Faulty
If the speaker functions only intermittently or the audio level is low:
1. Replace the speaker.
2. Check the continuity from the speaker connector SK2 to pin 17
(
SPK
–
) and pin 18 (
SPK
+
) of the control-head connector SK1 (see
Figure 15.2 ). If there is no fault, go to Step 3 . If there is still a fault,
go to “Volume Control Faulty” .
3. Reconnect the control-head loom, test the speaker to confirm the
removal of the fault, and return to
“Initial Tasks” on page 155 .
15.8 Volume Control Faulty
If the volume control works only intermittently, works only at full volume,
or does not work at all:
1. Disconnect the control-head loom.
2. Check that the resistance between pins 1 and 2 of the volume-control
potentiometer RV1 varies linearly between about 0
Ω
and 10k
Ω
. (see
Figure 15.2 ). If it does, go to Step 3. If it does not, go to Step 6 .
3. Replace the speaker.
4. Re-assemble the control head. Reconnect the control-head loom.
Confirm the removal of the fault, and return to
“Initial Tasks” on
page 155 .
5. Remove the control-head board.
6. Replace the potentiometer RV1. See Figure 15.1 .
7. Re-assemble the control-head board. Reconnect the control-head
loom. Confirm the removal of the fault, and return to
“Initial Tasks”
on page 155 .