IFR Com 120-b L.O. Unlocked

This forum exists for the purposes for discussing service monitors (This includes but is not limited to Motorola, HP, Aeroflex, GD, etc). Additional topics allowed include test procedures, interpretation of test results, where to find information about specific tests, antenna VSWR, return loss testing, duplexer and filter alignment, etc.

Moderator: Queue Moderator

Post Reply
New User
Posts: 1
Joined: Mon Sep 17, 2018 11:30 am

IFR Com 120-b L.O. Unlocked

Post by W7TIC »

hello, i have an IFR com 120-b that i acquired from a silent key. it powers up but the calibration expired, and the L.O is unlocked as well as third L.O. coarse unlocked, third L.O. fine is locked, analyzer and generator are unlocked. any help would be greatly appreciated. i plan to just use this for HAM radio stuff so nothing that would require calibration certification.
Posts: 470
Joined: Fri Feb 06, 2004 3:14 pm

Re: IFR Com 120-b L.O. Unlocked

Post by jry »

you could try and use an external 10Mhz reference.
That many loops unlocked points to a reference issue
I would look at the reference signal on one of the failing loops and make sure it matches the level and freq in the service manual on repeater builders.
If the external reference doesn't resolve the problem than you may have an issue with the reference assembly which is mounted on the right side front of the unit.
Post Reply

Return to “Test Equipment & RF Equipment Alignment”