Tait TM8000 Series Service Manual page 181

Figure 9.6 Components of the interface circuitry on the top-side of the main board near the
and
IF TOP
Task 2 —
Check Input Lines
TM8100 Mobile Radio Service Manual
May 2004 © Tait Electronics Limited
cans
For an input line suspected or reported to be faulty, proceed as follows:
1. For a suspect
go to Step 2.
2. For the suspect line, apply a 3.3 V DC test signal to a connector
mated to the radio connector in question.
3. Check the internal signal for the line under test. If 3.3 V DC is
present, go to Step 7. If it is not, go to Step 8.
4. For the
CH ON OFF
connector mated to the control-head connector. Check that there
is 3.9 V DC present on the
approximately equal to the radio's primary supply voltage,
nominally 13.8 V DC.
5. Remove the short on the connector. Check that, with
open-circuit, both
6. If the voltages given in Steps 4 and 5 are observed, go to Step 7.
If they are not, go to Step 8.
IF TOP CAN
line, go to Step 4. For all other input lines
CH ON OFF
line, apply a short to ground on pin 5 of a
ITF ON OFF
and
ITF ON OFF ITF PSU ON OFF
Diagnosis of Faults on Main Board
CDC TOP
CDC TOP CAN
line, and that
PSU ON OFF
CH ON OFF
are close to 0.0 V.
is
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