HW-101 Warble Problem

[Kechkaylo, David]

Dear Jordan:

Yeah, from Dave K. here, thanks also for the input. Many of the VFO
tuning caps used in the Heath VFOs (less expensive tuning caps) don't
have a ball bearing adjustment there at the end of the rotor shaft;
instead, this bearing is held onto the shaft end by the end of the
tuning capacitor tub or shell, which holds the entire stator plates,
know what I mean? The only way to add more force here is to clamp the
tub shell down tighter from front to back with a vise, but carefully.

Anyway, your suggestion is a possibility, too. I forgot about that.

Dave Kechkaylo

> ----------
> From:         Jordan Arndt[SMTP:jordana at nucleus.com]
> Sent:         Wednesday, November 11, 1998 4:34 PM
> To:   HEATH at LISTSERV.TEMPE.GOV
> Subject:      Re: HW-101 Warble Problem
>
> Jeffrey Weiss wrote:
> >
> > Hi, David,
> >
> > ** Reply to message from "Kechkaylo, David" <dkechkaylo at MDSROC.COM>
> on Tue, 10
> > Nov 1998 17:37:24 -0500
> >
> > > 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.
> >
> > Can this problem exist when you're ON a station and don't touch the
> VFO knob?
> > It warbles for me, then.
> > CW signals , most noticeable, pop up and down slightly in frequency
> about a
> > center frequency while I'm sitting back and just listening.
> >
> > If it really sounds like the same problem I will happily disassemble
> the darn
> > thing as you suggest. Cheap fix!
> >
> > Thanks,
> >
> > Jeffrey N0IRR
> >
> > >
> > > 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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>
> In my experience the problem is not with the Ball drive but the rear
> capacitor bearing... there is an adjustment but it needs to be cleaned
> as it is the ground contact for the rear of the rotor plates... you
> might get away with tightening the adjustment but it's safer to remove
> the VFO and clean and or replace the bearing... it does tend to
> "Flake"
> after some time... 73 de Jordan...
>
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