[sdiy] Pots for Oberheim SEM

[John L Marshall]

Okay, Here are the details on the ones that I have: The wiper on these 100k
linear pots goes through the usual 300 degree arc. But the 1/4 inch diameter
by 3/8 inch long shaft makes more than 10 complete revolutions. The 1/4 inch
shaft is only 0.100 inch diameter once inside the pot. Three large ball
bearings are pressed against the shaft and the outer shell. The bearings
make a planetary reduction. Cool!

 John

----- Original Message -----
From: KA4HJH <ka4hjh at gte.net>
To: <synth-diy at dropmix.xs4all.nl>
Sent: Sunday, January 27, 2002 10:35 PM
Subject: Re: [sdiy] Pots for Oberheim SEM


> >> I was recently fixing up a number of SEMs and then I discovered that
> >> one of the pots where not behaving well. It was one of the frequency
> >> pots which have a built-in gear and the bearing comes out in the back
> >> as three great metal balls rotating along.
>
> >I have a few ten-turn 100k linears that are as you describe. Is this what
> >you need?
>
> It's a single turn pot with a planetary drive. Ball bearings, no gears.
> There's a shaft and a sleeve. The sleeve turns the pot directly while the
> shaft has the reduction. Haven't seen those around lately.
>
> Still looking for one of those little black caps to replace the one that
> got lost.
> --
>
> Terry Bowman, KA4HJH
> "The Mac Doctor"
>
> "By the end of Chuck Statler's 'Rock Videos' of Devo we agreed that even
if
> Devo did not take the stage it was still the best concert any of us had
> ever attended." --Kim Thayil (Soundgardern), 1995