Check Power Control - Tait TM9100 Service Manual

Check the power-control circuitry if the clamp current for the PA driver is
Task 21 —
Check Power
correct or if the voltage at the
Control
Important
1.
2.
3.
4.
5.
6.
7.
8.
9.
TM9100 Service Manual
© Tait Electronics Limited August 2005
SET PWR
Ensure that the current limit on the DC supply is 3A.
And, when entering the CCTM command 304 z, do not
specify a value z higher than that recorded in
ure to do so might result in the destruction of the PA driver.
Enter the CCTM command 304 z (where z was recorded in
Note the current reading on the DC power supply.
Enter the CCTM command 114 0 to switch off the power.
Note the current reading on the DC power supply.
Compare the above current readings. The current should decrease by
an amount approximately equal to the offset given in
If it does, go to Task 26
not, go to Step 6.
Check that the voltage from the DAC is changing. Measure the
voltage at the test point (
PWR
Figure 11.12).
Enter the CCTM command 114 1023. The voltage should increase
to:
PWR test point: 2.4 ± 0.1V
Enter the CCTM command 32 to place the radio in receive mode.
If the voltage at the
PWR
Task 22. If it does not, go to
page 371.
Transmitter Fault Finding (50W/40W Radios)
test point is incorrect.
in "RF Signal Path" on page
) (see
CDC TX PWR CTL
test point increases as required, go to
"CODEC and Audio Fault Finding" on
Task 12. Fail-
Task 12).
Table 11.6.
293. If it does
Figure 11.11 and
285