[Hallicrafters] Caps on Selectivity switch was: RE: SX-100 Knobs

[David C. Hallam]

I had expected it to be a real horror story, but turned out to be not 
too bad.  Although that may be an understatement.  What I did was to 
take the switch loose from the front panel.  There was enough slack in 
the wires to allow me to pull the switch shaft through the chassis and 
rotate the rear of the switch up about 30-45 degrees.  I then replaced 
the capacitors and resistors on the back wafer.  Then I loosen the nuts 
on the two screws that hold the wafers on the switch.  By removing the 
rear wafer I was able to move it out of the way to get to the resistors 
and capacitors on the center wafer.  I didn't do anything with the 
resistor on the front wafer.

I used CDE 5% axial film capacitors from Mouser.  I also ordered some 
Panasonic 0.0047 and 0.01 3% radial polypropylene but they didn't have 
any in 0.022 uF.  I thought I might be able to find some 0.022 3% but 
didn't by the time my Mouser order arrived.

The rest of the film capacitors used were standard 10% axial.  All the 
replacement resistors were 1% metal film.

Hope that helps.

73 David
KW4DH

On 7/8/2013 5:41 PM, Chris Kepus wrote:
> Sounds like a first class project, David.
>
>
> Don't know about the knobs but I am curious about your re-cap effort.
> (others who have been "there - done that" feel free to chime in)
>
> What did you do to replace the caps on the selectivity switch? I am in the
> re-cap process working my way in that direction.  All I have to do to feel
> nauseous is look at that darn switch.  I think I'd rather chew on aluminum
> foil than attack that mess. ;-)  Anyway, please tell me how you accomplished
> the job and then tell me exactly how much fun it was (and that it isn't as
> bad a job as it looks.)
> Thanks es 73,
> Chris
> W7JPG
>
> -----Original Message-----
> From: hallicrafters-bounces at mailman.qth.net
> [mailto:hallicrafters-bounces at mailman.qth.net] On Behalf Of David C. Hallam
> ent: Monday, July 08, 2013 10:39 AM
> To: hallicrafters at mailman.qth.net
> Subject: [Hallicrafters] SX-100 Knobs
>
> Did Hallicrafters use anything protective varnish or similar on the knob
> skirts?  Mine were all yellowed and I assumed it was cigarette smoke
> residue.  After a trip through the ultrasonic cleaner, whatever was peeling
> off the skirt.  Nor just dissolving but peeling off in little pieces.
>
> I just finished the replacing of electrolytic and film capacitors. I used
> 10% polypropylene except for the pass band where I used 5%. I also replaced
> any resistors more than 7% out of spec using 1% metal film.
>
> It is working but is a little deaf.  I was listening to 40M with a 2 ft
> piece of wire.  Now to start the alignment.  It is SX-100 MK2.
>
> David
> KW4DH
>
> PS: All the film capacitors were the red Tiny Chiefs.  I tested all of them
> with my Sprague capacitor tester after removal.  I did only a quick test to
> see if a capacitor had rated capacitance.  Only one was bad but I knew it
> was bad before removal.  The resistor associated with it was burned.
>
> Since these capacitors were 60 years old, I decided it was time for them to
> be retired.
> --
>
>

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