Syn Lock Line - Tait TM9100 Service Manual

If all the critical inputs to the PLL are correct, check the
Task 10 —
Line
SYN LOCK
output.
1.
2.
3.
4.
5.
6.
TM9100 Service Manual
© Tait Electronics Limited August 2005
Enter the CCTM command 72 to determine the lock status in receive
mode. Note the status.
lock status=xyz (x=RF PLL; y=FCL; z=LO2) (0=not in lock; 1=in lock)
Check the line by measuring the voltage at pin 14 of IC503
SYN LOCK
(see Figure 9.2). The voltage should depend on the lock status as
follows:
lock status 111 or 110: 3.0 ± 0.3 V DC at pin 14 of IC503
lock status 011 or 010: 0 V DC at pin 14 of IC503
If the voltage measured in
page 187. If it is not, go to
Check for continuity between pin 14 of IC503 and the digital board
via R568 (see Figure 9.2) and L102 (see
If there is a fault, go to Step
faulty; replace the main-board assembly and go to
page 147.
Repair the fault. Confirm the removal of the fault and go to
Tasks" on page 147. If the repair failed or no fault could be found,
replace the main-board assembly and go to
page 147.
SYN LOCK
Step 2 is correct, go to "Loop Filter" on
Step 4.
Figure 9.6).
6. If there is no fault, the digital board is
"Final Tasks" on
"Final Tasks" on
Frequency Synthesizer Fault Finding
line
"Final
185