Tait TM9100 Service Manual page 334

If the RF output power and the supply current are uniformly low at all
Task 11 —
Power and Current
frequencies, one of the PAs is suspect or the input to the PAs is reduced.
Are Low
Check each PA in turn:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
Table 12.5 RF output power of individual RF power amplifiers at different frequencies
Frequency band
B1
H5
H6
334 Transmitter Fault Finding (25W Radios)
For the first PA (Q310), enter the CCTM command 331 to check the
DAC value of final bias 1 (
returned.
Note the current reading on the DC power supply.
Enter the CCTM command 331 1 to turn off final bias 1.
Enter the CCTM command 33 to place the radio in transmit mode.
Note the RF output power measured at the test set. This should be
as shown in Table 12.5.
If the RF power is correct, go to
second PA. If it is not, enter the CCTM command 32 to place the
radio in receive mode, and carry out
For the second PA (Q309), enter the CCTM command 332 to check
the DAC value of final bias 2 (
returned.
Note the current reading on the DC power supply.
Enter the CCTM command 332 1 to turn off final bias 2.
With the radio still in transmit mode, note the RF output power
measured at the test set. This should be as shown in
Enter the CCTM command 32 to place the radio in receive mode.
If the RF power measured in
Path" on page 354. If it is not, carry out
Lowest frequency
29 ± 5W
5 ± 5W
13 ± 5W
1). Record the value x
CDC TX FIN BIAS
Step 7 to repeat the check with the
Task 12
CDC TX FIN BIAS
Step 10 is correct, go to
Task 12
Frequency within band
Center frequency
34 ± 5W
12 ± 5W
19 ± 5W
© Tait Electronics Limited August 2005
and then Task 13.
2). Record the value y
Table 12.5.
"RF Signal
and then Task 16.
Highest frequency
29 ± 5W
27 ± 5W
28 ± 5W
TM9100 Service Manual