HW-101 Warble Problem

[Kechkaylo, David]

Dear Jeffery Weiss:

Many of the ball-bearing type of Jackson Drives used in several of the
Heathkit amateur products had this problem from time to time. There may
be spots on the dial as you're tuning around and you won't hear this;
other spots (depends on the point you are on the VFO cap rotation), and
you can't seem to tune the station in, it warbles so bad.....it is like
your "pie-eyed" or drunk.

Anyway, the problem is almost always a mechanical one here. Sometimes it
helps if you disassemble the VFO unit entirely, meaning the mechanical
VFO tuning capacitor from the VFO unit where it is mounted, the dial
assembly, and the Jackson drive unit. Then carefully put it back
together, but try to do this without any mechanical stress.....just let
the parts fit back together like they're supposed to...like a glove with
no forcing, according to the manual. No need here to get involved with
the electrical assembly, just the mechanical VFO capacitor drive parts.

Once assembled, tighten the front tuning knob set screws associated with
the Jackson drive after you've rotated the main tuning knob back and
forth a couple of times to make sure this drive and the VFO tuning
capacitor shaft are straight in line. Then tighten the set screws. This
makes sure, if the VFO cap is off center, you won't warp the Jackson
drive a bit as you go thru all the possible tuning rotation. Sometimes
it helps to squeeze the tabs tighter around the collar of the Jackson
drive, too, as this may make the tuning a bit stiffer to rotate, but may
reduce some of the "slop".

On the other hand, in difficult cases, direct replacement of the Jackson
drive cures the problem altogether. I hope this helps. The SB-104 uses
similar Jackson drives (actually two of them), and I absolutely HATE it
when the VFO warbles like that. The above explanation will sometimes
cure the problem on all Heath VFO units utilizing similar drive
mechanisms. If this solves your problem, then proceed to re-align the
VFO unit according to the manual. It won't be off by much, though.

Regards,

Dave Kechkaylo

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