Com120B deviation meter selftest fail

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lc4600
New User
Posts: 16
Joined: Mon Aug 03, 2009 7:29 am

Com120B deviation meter selftest fail

Post by lc4600 »

Com120B deviation meter self test fail at boot up
I calibrated both gen deviation and rec deviation meter. They both work fine when checked in gen and rec. Any insight on the deviation meter check during boot up self-test would be appreciated.
I'm kinda stuck where to go when the meter is working fine in the rec screen but fails during self test.
I replaced the baseband with known working one.
I replaced the receiver WKWO.

Carl NØPXJ
jry
Posts: 465
Joined: Fri Feb 06, 2004 3:14 pm

Re: Com120B deviation meter selftest fail

Post by jry »

the COM-120 loops back using the RF path in the power termination assembly for the various tests.

The problem may be the RF section specifically the synthesizer sections not locking at the specific frequency used during the self test.

Usually its the 1st LO modules that have issues ...there are two of them used for the independent generate and receive.

I believe in previous posts the specific frequency used in the self test was mentioned.

Other option may be to swap the modules between units.... like the synthesizer and generate.
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