On/Off Key Faulty - Tait TM8100 mobiles Service Manual

14.8

On/Off Key Faulty

436 Fault Finding of Control Head with Graphical Display
When battery power (13.8V) is applied to the radio, a press of the
will create an active low signal (
the power-on or power-off sequence. This key-press will also be detected
by the FPGA of the control head through Q611 as an active high signal
( ). For more information on the start-up process, refer to
3 3
POWER ON OFF V
"Software Architecture" on page
Figure 14.9 Circuit diagram of the
Control-Head 13V8
Connector
R606
CH ON OFF
J103
9
R610
Power
On/Off
If the key is faulty:
/
ON OFF
1. Use isopropyl alcohol and a soft lens-cleaning cloth to clean the pads
S610 on the control-head board for the
2. Check the
CH ON OFF
head connector J103.
J103 pin 9: 13V
If the signal is approx. 13V, continue with
If near or at ground, continue with
3. Visually inspect pin 9 of connector J103 for open or shorted contacts.
4. Verify the source of the signal to pin 9 of connector J103 from the
radio (without the control-head connector).
5. Visually inspect R610, R606, and R624 for short-circuit to adjacent
components. Replace if necessary. Return to
6. Visually inspect R610 for shorted or open circuits. Repair if
necessary. Retest switch.
7. Verify continuity between R610 and switch S610, and continuity
between switch S610 and ground.
If the continuity cannot be restored, replace the control-head board.
) back to the radio body to initiate
CH ON OFF
49.
key
/
ON OFF
3V3
R628
R626
Q611
R627
1
S610
2
ON
signal level from the radio at pin 9 of the control-
Step 3.
© Tait Electronics Limited November 2007
/
ON OFF
POWER ON OFF 3V3
FPGA
key.
/
OFF
Step 5.
Step 2.
TM8100/TM8200 Service Manual
key