[Hallicrafters] sx-28 Silver Mica Re-cap kit

[Rob Copeland]

Hi Guys,

While this and all the other suggestions are great, I have already done this
and more I have measured capacitance on most of the silver micas in my radio
and found every one that I have measured to be out of tolerance. This is why
I replaced them in the RF Section ( ...besides might as well considering
what a pain it is to get in there ...right?!?! ;) ) My preferance is 5% or
less although I am sure that 10% is probably acceptable.

I was hope that someone could just quote me a price and save me the work of
going through the schematic again. I will compose a list of what I need and
post it. BTW the crystal is within spec.

Thanks!

Rob Copeland

-----Original Message-----
From: hallicrafters-bounces at mailman.qth.net
[mailto:hallicrafters-bounces at mailman.qth.net]On Behalf Of Jim Wilhite
Sent: Friday, November 03, 2006 6:36 PM
To: Hallicrafters at mailman.qth.net
Subject: Re: [Hallicrafters] sx-28 Silver Mica Re-cap kit


Could it be the knob in not in the right place on the
phasing shaft?  Do you see a notch and another 180 degrees
opposite the first?  If so, put the cap at 1/2 engaged then
put the knob back on with the 0 at the mark and recheck.
You might not need to replace the micas.

Putting a signal generator through the crystal will check
it, but remember you will see some loss of signal level
through it.

If you can's find a peak for the crystal within about 1.5 Kc
either side of the design frequency, then do as suggested
before, remove it, disassemble carefully and clean with
alcohol, then carefully reassemble.  Before removing it,
either memorize the layout of the wiring, or take a picture
of it, then when you reinstall, do so the way it was before
you disturbed it.

73  Jim
W5JO



> Hi Everyone,
>
> I have rebuilt my sx-28 to sx-28a specs everything minus
> the silver mica
> caps that are in the IF cans and the rest of the circuit
> minus those that
> are in the RF section those were done when the RF section
> was rebuilt. The
> radio works great except for The Crystal Filter. I am
> suspecting that the
> silver micas are to blame seeing how that is the only
> thing I have not
> replaced in the radio. All caps and resistors plus the
> silver micas in the
> rf section have been replaced.
>
> So I am curious if anyone has a re-cap kit for the silver
> micas minus the RF
> section?
>
> Thanks,
>
> Rob Copeland


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