Check Switching To Transmit Mode - Tait TM9100 Service Manual

If no transmit frequency is detected in the check of the transmit VCO, first
Task 26 —
Check Switching
check that the transmit-receive switch is functioning correctly.
to Transmit Mode
1.
2.
3.
4.
5.
6.
204 Frequency Synthesizer Fault Finding
Resolder R542 in position (see
Enter the CCTM command 335 1 to switch on the supply to the
transmit VCO.
Measure the voltage at the second collector (pin 6) of Q506
(see Figure 9.9). The voltage should be:
pin 6 of Q506: 5.0 ± 0.3 V DC (after entry of CCTM 335 1)
Enter the CCTM command 335 0 to switch off the supply.
Again measure the voltage at the second collector of Q506.
pin 6 of Q506: 0 V DC (after entry of CCTM 335 0)
If the voltages measured in
Task 27. If they are not, the switching network is suspect; go to
Task 21.
Figure 9.9).
Step 2 and Step 4 are correct, go to
TM9100 Service Manual
© Tait Electronics Limited August 2005