[Hallicrafters] Caps on Selectivity switch - Additional Info

[David C. Hallam]

I had tested all of the CD Tiny Chiefs for capacitance as I removed 
them.  To the limits of the calibration of my Sprague TO-4 tester, they 
were close to spec except for one.  I did not test insulation 
resistance.  I happened to have one of the removed 0.022 uF capacitors 
left on the bench.  I decided to run an insulation resistance check on 
it.  To my surprise, it read 0 which meant it was less than 150 Meg ohm 
on my tester.  I then took a new 0.022 uF and tested it.  The reading 
was about 200K Meg ohms.  The tester manual says that a film resistor 
should test at least 5K Meg ohm.

What does this mean?  I don't know.  I would seem that maybe this 
capacitor could be leaky under some circumstances.

David
KW4DH

On 7/8/2013 6:45 PM, Jim Liles wrote:
> 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
>


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