Tait TM8100 mobiles - Page 322

322 Transmitter Fault Finding (>25W) TM8100/TM8200 Service Manual
© Tait Electronics Limited November 2007
Task 2 7 —
Output of First
Stage of Exciter
If the synthesizer output is correct, check the output at C3505 for the
VHF/UHF bands or C313 for the K5 band of the first stage of the exciter
circuit.
1. If not already done, remove the
PAD TOP can.
2. Enter the CCTM command 326 x, where x defines the power level
selected in Task 26
.
3. Enter the CCTM command 101 x x 0, where x is the frequency
selected in Task 26
.
4. Enter the CCTM command 33 to place the radio in transmit mode.
5. Measure the RF voltage after C3505 for the VHF/UHF bands
(see Figure 11.21) or Q300 for the K5 band (see Figure 11.22).
(Use an RFP5401A RF probe or the equivalent.) The required
voltage should be as given in Table 11.8 (B1), Table 11.9 (G2),
Table 11.10 (H5), Table 11.11 (H7), or Table 11.12 (K5).
6. Enter the CCTM command 32 to place the radio in receive mode.
7. If the voltage measured above is correct, go to Tas k 29
. If it is not, go
to Step 8.
8. Check the components around Q3501 for the VHF/UHF bands
(see Figure 11.21) or Q300 for the K5 band (see Figure 11.22).
9. Repair any fault revealed by the above checks. Replace Q3501 for
the VHF/UHF bands (see Figure 11.21) or Q300 for the K5 band
(see Figure 11.22) if none of the other components is faulty.
10. Confirm the removal of the fault and go to “Final Tasks” on
page 163. If the repair failed, replace the board and go to “Final
Tasks” on page 163.