[sdiy] Polymoog

[Gene Stopp]

Here's my input - 

The keys are weighted with lead weights. Once it's cleaned up it's not too
heavy, so I'm wondering if you're having what I will call the "Polymoog
sticky key syndrome". Here's the deal: the keyboard is the traditional
old-style Pratt/Read mechanics, which consists of plastic keys screwed on to
metal channels which   pivot at the back with coil springs pulling them into
the rest position. Under the channels, are 90 degree rocker arms which
translate the downward motion into a sideways motion, which pulls a rubber
spring holder into the bussbars. Anybody who has taken apart a Minimoog
keyboard will know what I mean here. Anyway, under the channel, on the
rocker arm, is a rubber button which provides the contact point between the
channel and rocker arm. On my Polymoog, a lot of these were gooey with some
sticky greasy substance, kind of like a combination of pancake syrup and
vaseline. This makes the key very hard to depress, since the rubber button
sticks to the sides of the channel. One solution is to take the whole
keyboard assembly apart and clean everything with spirits. Another solution
(I'm lazy sometimes) is to get yourself a can of Tri-Flow (which I normally
use on bicycles) with an extension nozzle and stick the nozzle way up into
the channel from under the front of the keys and spritz a couple of drops
into the rubber button contact area. Tri-Flow has teflon in it and is kind
of an ultra-WD40. You do have to unbolt the keyboard assembly to tip it up
to do this. My disclaimer here is that there has been no testing of the
eventual possible side effects of this substance on Polymoog keyboards.

Regarding the velocity sensitivity - there is a slider which I think is
called "Keyboard Dynamics". If you're in VAR mode, and this slider is all
the way up, there will be no velocity sensitivity since the value will be at
max already. If you back this down, the overall instrument volume starts to
drop and velocity starts to work. If you change the mode to "Piano", then
you should have velocity sensitivity. If you don't, I would suspect
something wrong in the Dynamics circuitry which keeps it at max value.

Regarding the tar, yuk sorry to hear that... it happens to Taurus pedals too
under the foot sliders. I hate that stuff.

Best Regards,

- Gene

Gene Stopp
Senior Support Engineer
Ixia

ph. USA 818-871-1800 x.3214
fax USA 818-871-1805


-----Original Message-----
From: Happy Harry [mailto:paia2720 at hotmail.com]
Sent: Friday, July 27, 2001 9:53 AM
To: oakley at techrepairs.freeserve.co.uk; synth-diy at dropmix.xs4all.nl
Subject: Re: [sdiy] Polymoog


Barbed wire goes stiff through work hardening dur to
the vibration of the wind whistling through it for
years...

Has yours been in the breeze long... or played THAT
heavily ???  (i guess probably not....)

H^) harry


>From: "Tony Allgood" <oakley at techrepairs.freeserve.co.uk>
>Reply-To: "Tony Allgood" <oakley at techrepairs.freeserve.co.uk>
>To: "Synth DIY" <synth-diy at dropmix.xs4all.nl>
>Subject: [sdiy] Polymoog
>Date: Fri, 27 Jul 2001 14:50:22 +0100
>
>Hi all,
>
>Well, this really is being a bit of a pain literally. And to be honest,
>if I could have picked it up, I would have thrown it out the window last
>night. I did my back in lifting the thing off the bench yesterday.
>
>But its starting to sound OK, although the slider pots are terrible and
>they have this plastic tar all over them. Sort of reminiscent of the
>Moog Rogue here. And after two hours with a box full of cotton buds and
>IPA, that's isopropyl alcohol, not the beer, I have only got about 90%
>of the keys to work. And the velocity response is zero. Is it all worth
>it??? I really don't know. The keyboard is so heavy. Is it supposed to
>be like that? It reminds me of the piano we used to have in the practice
>room at school. After ten minutes of playing, your hands ache all over.
>If this cannot be fixed the whole thing is going to spare parts.
>
>So my question is: is the keyboard problem a spring problem or a feature
>of the keyboard itself. Do they go bad? I know barbed wire goes stiff
>after a few years out in the open. Florian, Gene, are yours this bad?
>
>Many thanks,
>
>Tony Allgood, Penrith, Cumbria, England
>
>Oakley Modular Synth and TB3030:
>www.oakleysound.com/projects.htm
>My music: www.mp3.com/taklamakan
>
>
>


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