To Next Page

To Previous Page

162 Power Supply Fault Finding TM9100 Service Manual

Task 6 —

Check Provision of

External Power

External power is supplied to pin 8 of the auxiliary connector SK101.

The power is normally switched, but will be unswitched if all the links LK5

to LK8 are inserted. (With all the links inserted, the power at the other

connectors is also unswitched.)

External power, either switched or unswitched, is supplied to pin 2 of the

control-head connector SK100. The power is switched or not depending on

the links LK5 and LK6:

■ switched power: LK5 in, LK6 out

■ unswitched power: LK5 out, LK6 in

External power is also supplied to pin 1 of the internal-options connector

SK102. The power is switched or not depending on the links LK7 and LK8:

■ switched power: LK7 in, LK8 out

■ unswitched power: LK7 out, LK8 in

If there is a fault with the supply of external power to any of these

connectors, first confirm the link settings required and then carry out the

following procedure:

1. With the radio powered up, confirm that 13.8V DC is present at pin

3 of IC605 (see Figure 7.1) and more than 3V DC at pin 2.

2. Check that 13.8 V is present at pin 5 of IC605. If there is, go to

Step 3. If there is not, go to Step 4.

3. Check for an open circuit between pin 5 of IC605 and the relevant

pin of the connector in question. Repair any fault, confirm the

removal of the fault, and go to “Final Tasks” on page 147. If the

repair failed or the fault could not be found, replace the main-board

assembly and go to “Final Tasks” on page 147.

4. Check for continuity between pin 5 of IC605 and the relevant pin of

the connector in question. Check for shorts to ground, check C718

at the auxiliary connector (see Figure 7.1), and check C715 at the

internal-options connector (see Figure 8.2).

5. Repair any fault found in the above checks. If no fault could be

found, replace IC605.

6. Confirm the removal of the fault and go to “Final Tasks” on

page 147. If the repair failed, replace the main-board assembly and go

to “Final Tasks” on page 147.

Tait TM9100 Service Manual

Other manuals for Tait TM9100