Lock Status - Tait TM9100 Service Manual

10.
A lock error indicates that the frequency synthesizer, FCL or second LO is
Task 2 —

Lock Status

out of lock. To determine which is faulty, check the lock status as described
below.
1.
2.
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7.
8.
172 Frequency Synthesizer Fault Finding
If the lock status is 111 or 110, the synthesizer is functioning in the
receive mode, and the power supplies and PLL are functioning
correctly. Go to "Loop Filter" on page 187
VCOs, and buffer amplifiers. If the lock status is 011 or 010, the
synthesizer is faulty in the receive mode. Go to
page 173.
If not already done, place the radio in CCTM.
Program the radio with the receive frequency of a channel that is
known to be out of lock: Enter the CCTM command 101 x x 0,
where x is the frequency in hertz.
Enter the CCTM command 72 to determine the lock status in receive
mode. Note the response. The action required depends on the lock
status as described in the following steps.
lock status=xyz (x=RF PLL; y=FCL; z=LO2) (0=not in lock; 1=in lock)
If the lock status is x0x, where x is 0 or 1, the FCL is suspect; go to
"Power Supply for FCL" on page
If the lock status is 011, the synthesizer is suspect, although the power
supplies are functioning correctly; go to
If the lock status is 010, the synthesizer and second LO are both out
of lock. First investigate the synthesizer, excluding the power supplies;
go to "Loop Filter" on page
later.
If the lock status is 110, the second LO is out of lock. Go to
"Receiver Fault Finding" on page
If the lock status is 111, this implies normal operation. But if the lock
error persists, replace the main-board assembly and go to
Tasks" on page 147.
to check the loop filter,
"Power Supplies" on
215.
"Loop Filter" on page
187. If necessary, investigate the receiver
227.
TM9100 Service Manual
© Tait Electronics Limited August 2005
187.
"Final