[Heathkit] Mohican Shaft coupler, Antenna Trimmer capacitor, need information.

[WA9VRH Larry]

Hi Phil,

I have said bushing from a Mohican and be glad to send it to you. Is
your address ok on QRZ?

73 Larry WA9VRH

----- Original Message -----
From: "Philip Atchley" <beaconeer at sbcglobal.net>
To: <heathkit at mailman.qth.net>
Sent: Monday, February 21, 2005 12:45 PM
Subject: [Heathkit] Mohican Shaft coupler, Antenna Trimmer capacitor,need
information.


> Hi,
>
> Today I thought that perhaps I'd go ahead and do an RF alignment of the
> Mohican that I've been overhauling (the set now plays pretty good).
>
> Anyway, I noticed that the Ant Tuning control seemed quite stiff and
> seemed to turn a 'little' easier over part of the range.  Examination
> disclosed the following.
>
> 1.  The Ant Trimmer capacitor has a shaft smaller than the standard 1/4
> inch shaft.
>
> 2.  The shaft coupler is the standard 1/4 inch to 1/4 inch aluminum job
> with two setscrews (1 each end).
>
> 3.  The shaft to the front panel knob is a standard 1/4 inch phenolic or
> similar material.
>
> 4.  The specified trimmer capacitor for this circuit is 3 to 20 pF, Part
> Number 26-24.  This one has about 20 plates with a printed P/N of 20M11.
> It DOES have the correct rectangular threaded section to fit the hole.
> But it seems to have far more plates than 20pF would indicate.
>
> 5.  The "binding" is occurring because when you tighten the setscrew
> down on the capacitor end of the coupler, the tuning capacitor shaft
> isn't centered in the oversized hole, so the phenolic shaft isn't lined
> up with the front panel.  This causes the entire thing to twist back and
> forth as you tune.  It also somewhat displaces the bracket the capacitor
> is on during part of the rotation.
>
> FIRST:  A QUESTION.  Does anybody know if that 1/4 inch coupler was the
> "standard" for this receiver.  The limited parts list from BAMA doesn't
> show that part.
>
> NEXT:  If somebody has a Mohican and it's not too inconvenient, could
> they look at the Antenna trimmer capacitor, and perhaps the coupler and
> see if it fits the descriptions I've given here.  I don't want to
> proceed with alignment until I know everything is "right". IF the
> capacitor DOES have too many plates/capacity I can always put a series
> capacitor in the circuit to reduce it's range (right now it seems like I
> have to fully open the plates to get it to align).
>
> FINALLY: I figure that if all else fails, I can fill part of one end of
> the shaft coupler (side opposite of the setscrew) with JB Weld, let it
> set up and then "file to fit".  I DON'T have the shop facilities to make
> a correct coupler or bushing to fit.
>
> It's been a lot of work, but when it's finished I THINK that it is going
> to be one nice Mohican, just like new. . .
>
> 73 de Phil,  KO6BB
> http://www.geocities.com/ko6bb/
> Merced, Central California, 37.3N  120.48W  CM97sh
>
>
>
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