Check Transmit-Receive Switch - Tait TM9100 Service Manual

If no frequency is detected in the check of the VCO, first check that the
Task 31 —
Check Transmit-
transmit-receive switch is functioning correctly.
Receive Switch
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
212 Frequency Synthesizer Fault Finding
Resolder R542 in position (see
Remove the can.
VCO BOT
Enter the CCTM command 335 0 to switch on the supply to the
port.
Measure the voltage at pin 2 of D5004 (see
noise might be observed.) The voltage should be:
pin 2 of D5004: 5.0 ± 0.3 V DC (after entry of CCTM 335 0)
Enter the CCTM command 335 1 to switch off the supply.
Again measure the voltage at pin 2 of D5004.
pin 2 of D5004: 0 V DC (after entry of CCTM 335 1)
If the voltages measured in
Step 8. If they are not, the switching network is suspect; go to
Task 32.
Enter the CCTM command 335 1 to switch on the supply to the
port.
Measure the voltage at pin 1 of D5004 (see
noise might be observed.) The voltage should be:
pin 1 of D5004: 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 pin 1 of D5004.
pin 1 of D5004: 2.1 ± 0.4 V DC (after entry of CCTM 335 0)
If the voltages measured in
Task 33. If they are not, the switching network is suspect; go to
Task 32.
Figure 9.12).
Figure 9.13). (Some RF
Step 4 and Step 6 are correct, go to
Figure 9.13). (Some RF
Step 9 and Step 11 are correct, go to
TM9100 Service Manual
© Tait Electronics Limited August 2005
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