Tait TM8100 mobiles Service Manual page 359

Task 11 —
Power and Current
Are Low
Table 12.5 RF output power of individual RF power amplifiers at different frequencies
Frequency band
A4
B1
C0
D1
H5
H6
TM8100/TM8200 Service Manual
© Tait Electronics Limited November 2007
If the RF output power and the supply current are uniformly low at all
frequencies, one of the PAs is suspect or the input to the PAs is reduced.
Check each PA in turn:
For the first PA (Q310), enter the CCTM command 331 to check the
1.
DAC value of final bias 1 (
returned.
2. Note the current reading on the DC power supply.
Enter the CCTM command 331 1 to turn off final bias 1.
3.
Enter the CCTM command 33 to place the radio in transmit mode.
4.
5. Note the RF output power measured at the test set. This should be
as shown in Table
6. 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
7.
the DAC value of final bias 2 (
returned.
8. Note the current reading on the DC power supply.
Enter the CCTM command 332 1 to turn off final bias 2.
9.
10. 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.
11.
12. If the RF power measured in
Path" on page 379. If it is not, carry out
Lowest frequency
24 ± 5W
29 ± 5W
23 ± 5W
33 ± 5 W
5 ± 5W
13 ± 5W
1). Record the value x
CDC TX FIN BIAS
12.5.
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
Centre frequency
25 ± 5W
34 ± 5W
22 ± 5W
28 ± 5 W
12 ± 5W
19 ± 5W
Transmitter Fault Finding (25W)
and then Task 13.
2). Record the value y
Table 12.5.
"RF Signal
and then Task 16.
Highest frequency
25 ± 5W
29 ± 5W
17 ± 5W
29 ± 5 W
27 ± 5W
28 ± 5W
359