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

[Jim Liles]

Good job David:

Perfect solution and good choice of components.

Chris, that is a superb radio --- what model is it?

Kindest regards Jim K9AXN


-----Original Message----- 
From: David C. Hallam
Sent: Monday, July 08, 2013 5:05 PM
To: Chris Kepus
Cc: hallicrafters at mailman.qth.net
Subject: Re: [Hallicrafters] Caps on Selectivity switch was: RE: SX-100 
Knobs

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.
> --
>
>

-- 
"I predict future happiness for Americans if they can prevent the government 
from wasting the labors of the people under the pretense of taking care of 
them."
Thomas Jefferson

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