Tait TM8100 mobiles Service Manual page 183

Task 2 —
Check Input Lines
Task 3 —
Bi-directional Lines
TM8100/TM8200 Service Manual
© Tait Electronics Limited November 2007
For an input line suspected or reported to be faulty, proceed as follows:
1. For a suspect
CH ON OFF
to Step 2.
2. For the suspect line, apply a 3.3V DC test signal to a connector mated
to the radio connector in question.
3. Check the internal signal for the line under test. If 3.3V DC is
present, go to Step
4. For the
CH ON OFF
mated to the control-head connector. Check that there is 3.9V DC
present on the
ITF ON OFF
equal to the radio's primary supply voltage, nominally 13.8V DC.
5. Remove the short on the connector. Check that, with
open-circuit, both
6. If the voltages given in
If they are not, go to
7. The fault lies with the radio's internal circuitry. If the power-supply
circuitry or the CODEC and audio circuitry is suspect, continue with
the fault diagnosis as in
and "CODEC and Audio Fault Finding" on page
If the digital board is suspect, replace the board and go to
Tasks" on page
8. The fault lies in the filtering, basic processing, or connector for the
line under test. Re-solder components or replace faulty components
as necessary. Confirm the removal of the fault and go to
on page 163. If the fault could not be found, replace the board and
go to "Final Tasks" on page
For a bi-directional line suspected or reported to be faulty, proceed as
described below. In the procedure the direction of the line will need to be
configured. For information on this topic consult the on-line help facility
on the programming application's "Programmable I/O" page.
1. Configure the suspect line as an output, and then carry out the
procedure given in
2. Configure the suspect line as an input, and then carry out the
procedure given in
line, go to Step
7. If it is not, go to
line, apply a short to ground on pin 5 of a connector
line, and that
and
ITF ON OFF ITF PSU ON OFF
Step 4 and Step 5
Step 8.
"Power Supply Fault Finding" on page 169
163.
163.
Task 1.
Task 2.
4. For all other input lines go
Step 8.
is approximately
PSU ON OFF
CH ON OFF
are close to 0.0V.
are observed, go to
399, respectively.
"Final
"Final Tasks"
Interface Fault Finding
Step 7.
183