TM9100 Service Manual Transmitter Fault Finding (50W/40W Radios) 307
© Tait Electronics Limited August 2005
Task 32 —
Repair Circuitry
If the RF output power measured in Task 31 is low, there is a fault in the
circuit between the common drain of the PAs and the test capacitor.
1. If not already done, remove the
PAF TOP can.
2. Check for faulty, shorted or misplaced components in the circuit
between the test capacitor and the common drain of Q309 and Q310
(see Figure 11.8 and Figure 11.9).
3. Repair any fault revealed by the above checks and go to Step 5. If no
fault could be found, go to Step 4.
4. Remove the test lead and test capacitor, resolder the coupling
capacitors C348, C349 and C350 in position (see Figure 11.25 and
Figure 11.26), and go to Task 26
.
5. With the test lead still connected to the test set, enter the CCTM
command 326 5 to set the transmitter power level to the maximum.
6. Enter the CCTM command 101 x x 0, where x is the lowest
frequency (in hertz) for maximum power, as given in Table 11.8
(B1 band), Table 11.9 (H5) or Table 11.10 (H7).
7. Enter the CCTM command 33 to place the radio in transmit mode.
8. Measure the RF output power. This should be:
9. Enter the CCTM command 32 to place the radio in receive mode.
10. Enter the CCTM command 101 x x 0, where x is the highest
frequency (in hertz) for maximum power, as given in Table 11.8
(B1 band), Table 11.9 (H5) or Table 11.10 (H7).
11. Repeat Step 7 to Step 9.
12. Remove the test lead and test capacitor, and resolder the coupling
capacitors C348, C349 and C350 in position (see Figure 11.25 and
Figure 11.26).
13. If the power in both the above cases is now correct, the fault has been
rectified; go to “Final Tasks” on page 147. If it is not, the repair
failed; replace the main-board assembly and go to “Final Tasks” on
page 147.
RF output power: more than 70W (B1 band)
more than 60W (H5, H7 bands)
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