[Milsurplus] BC-342N Volume Control

[Mark K3MSB]

Well,  rotating the knob CW and pulling, after loosening the screw,
didn't do anything,  but CCW and a little force worked.  Knob and
skirt came off nicely.   The DxOxit cleaned up the audio pots too.

Thanks!!

Mark K3MSB

On Thu, Sep 25, 2008 at 11:19 PM,  <WA5CAB at cs.com> wrote:
> Mark,
>
> I just removed the VOL knob from a BC-312 here to be sure memory was
> correct.  The knob has a brass core that the bakelite was molded around.
> The setscrew hole is tapped through the brass.  The panel face of the
> bakelite has three tapped holes (probably #3-48 but I didn't actually check
> as it doesn't matter to your problem).  The dial graduations are on a disk
> (skirt) that is slightly coned and attached to the face of the knob with
> three screws.  First thing you do not want to do is to try to remove the
> knob by pulling or prying on the skirt.  99 and 44/100% probability that you
> will ruin it.
>
> The knob is, as you assumed before it wouldn't come off, held onto the solid
> potentiometer shaft by the single setscrew.  What's happened is that
> tightening the screw has raised a burr on the shaft.  Someone before you
> tried to remove it and twisted the knob with the shaft locked by the stop at
> one end of rotation.  So there is now a circumferential groove cut in the
> brass.  The knob will rotate but won't come off.
>
> Pull lightly on the knob and rotate it CCW until the zero lines up with the
> line on the panel.  The setscrew hole is now probably over the burr (I'm
> assuming you already completely removed the screw) unless the last person to
> tighten the screw didn't have the knob in the right position.  Push the knob
> sideways toward the screw hole and pull hard.  You might be able to get it
> to move and come off.
>
> If not, you are going to have to make or modify a guillotine puller that
> fits the reduced knob diameter just above the skirt.
>
> In a message dated 9/25/2008 9:32:45 PM Central Daylight Time,
> mark.k3msb at gmail.com writes:
>
> One evening after the local radio club meeting,  one of the members
> says he something in his trunk that I may be interested in.  A nice
> BC-342-N followed me home that evening.  The guys uncle had passed
> away, and he used the 342 fairly regularly until his death.  Nice
> condition inside and out (although I could do without the SO-239 below
> the band change knob).   It works,  but needs restoration throughout.
>
> The Volume knob is scratchy, so I thought I'd remove it and hit it
> with some DeOxit.  Seemed simple enough.
>
> I feel embarrassed to ask this, but how the devil do you get the knob
> off?   The screw comes out nicely,  but the knob will not budge, and I
> don't want to force it.   I tried putting a few drops of WD-40 in the
> hole, but that didn't work.  With the screw loose, the knob (not the
> shaft) will turn freely, so something's holding it in.
>
> Second,  looking at the pots,  I don't really see a way to get any
> DeOxit inside;  not any large openings near the lugs (which I guess
> makes sense as it was intended to operate in harsh environments.  So,
> suggestions on cleaning it?
>
>
> Robert & Susan Downs - Houston
> wa5cab dot com (Web Store)
> MVPA 9480