[Boatanchors] [BoatAnchors] The "Hallicrafters Wobble."

[Garey Barrell]

Dave -

I can't find the article......  I believe the problem is that the thin metal dividers between 
sections of the VC are very flimsy, and it only takes a tiny bit of movement on BAND 4 to shift 
the frequency of the HFO.  I think the variable capacitors were the weakest link in 
Hallicrafters radios. I've found all sorts of problems like bearings not 'loaded', to 
non-centered plates, to ....

But heavy wire soldered to the front and back frame and soldered to each of the divider plates 
helps a lot.......

73, Garey - K4OAH
Glen Allen, VA

Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line
and TR-4/C Service Supplement CDs
<www.k4oah.com>

David Stinson via BoatAnchors wrote:
> Just about every Hallicrafters receiver I've ever resurrected has what I call the 
> "Hallicrafters Wobble" on Band 4.
> It's mechanical instability.  I just gave a nice SX-110 CPR
> and, while it sounds really nice on bands 1-3, a fan on the
> end of the bench makes the Oscillator "dance" on Band 4.
> I'm sure it's also wobbling on the other bands but since
> the operating freq is lower, it's not so pronounced.
> Has anyone investigated this "wobble?"  Is it centered on the bandset/bandspread variable 
> caps, which seems most likely,
> or elsewhere in the Osc.?   Has anyone tried to correct it?
>
> 73 Dave AB5S
>