Tait TP9100 - Page 247

TP9100 Service Manual Transmitter Fault Finding 247
© Tait Electronics Limited May 2005
Task 22 —
Repair PIN switch
If the RF power at the PIN switch is low, the switch is not drawing the
expected current. Check the circuit as follows:
1. Check D101 (see Figure 10.11). If it is not faulty, go to Step 2.
If it is, replace D307 and go to Step 3.
2. Check the +5
V0 TX supply to the PIN switch via the following
components:
■ B1 band: L123 (see Figure 10.11),
D103, L109, R189, R190, R192 (see Figure 10.12)
■ H5, H6 bands: L123, L126 (see Figure 10.11),
D105, D106, D107, R171, R172, R173 (see Figure 10.12)
Replace any faulty component.
3. 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.
4. Enter the CCTM command 101 x x 0, where x is the lowest
frequency (in hertz) for maximum power, as given in Table 10.6
(B1), Table 10.7 (H5), or Table 10.8 (H6).
5. Enter the CCTM command 33 to place the radio in transmit mode.
6. Again measure the RF output power. This should exceed 5W.
7. Enter the CCTM command 32 to place the radio in receive mode.
8. Enter the CCTM command 101 x x 0, where x is the highest
frequency (in hertz) for maximum power, as given in Table 10.6
(B1), Table 10.7 (H5), or Table 10.8 (H6).
9. Repeat Step 5 to Step 7.
10. Remove the test lead and test capacitor, and resolder the blocking
capacitors C160 (see Figure 10.11) in position.
11. If the power in both the above cases is now correct, the fault has been
rectified; go to “Final Tasks” on page 134. If the repair had failed,
replace the main board and go to “Final Tasks” on page 134.
RF output power: more than 6W (B1), more than 5W (H5, H6)