HW-101 Warble Problem

[Jeffrey Weiss]

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
>
> --- --- --- --- --- --- --- --- --- --- --- --- --- --
> To subscribe: listserv at listserv.tempe.gov
> and in body: subscribe HEATH yourfirstname yourlastname
> To unsubscribe:  listserv at listserv.tempe.gov
> and in body: signoff HEATH
> Archives for HEATH: http://www.tempe.gov/archives
> --- --- --- --- --- --- --- --- --- --- --- --- --- --

--- --- --- --- --- --- --- --- --- --- --- --- --- --
To subscribe: listserv at listserv.tempe.gov
and in body: subscribe HEATH yourfirstname yourlastname
To unsubscribe:  listserv at listserv.tempe.gov
and in body: signoff HEATH
Archives for HEATH: http://www.tempe.gov/archives
--- --- --- --- --- --- --- --- --- --- --- --- --- --