No FT-980 ever had GEN TX unless it was modified by the owner.? I did have one years ago that Phil K4DPK modified? and he did not use the risky Yaesu recommended mod.?
-----Original Message-----
From: Fred_N8YX
Sent: Jun 5, 2020 1:30 PM
To: [email protected] Subject: Re: [Yaesu-FT-980] GEN mode probelm
I did a little research in the Technical Supplement. Short of a circuit malfunction or (unknown) modification, there should be no way that Ham/Gen VFO selection logic should unbalance the various mixers, the Balanced Modulator or alter the BFO frequency.
So, a couple of questions: Did the radio ever work properly? If so, what happened immediately prior to the failure?
One thing I would check is the setting of TC4001 (another member hinted about this). Consult the Technical Supplement for the procedure and the frequency to which it is set. The symptoms are characteristic of a malfunctioning Balanced Modulator; that is, one whose Carrier Null point isn't set properly. Since everything in this rig is tied to a couple of reference oscillators and logically derived from them, we need to figure out if it's an adjustment issue or a logic fault.
