[sdiy] Polysix keys

[Bob Weigel]

WHen the traces start to get fried around the battery a lot of things 
can be affected indeed.

The contacts are weird on these things. Occasionally you have ones that 
just didn't get enough of the conductive part in the mix and they only 
conduct on the very surface and once it's worn they are done.  I've seen 
lots  of them (as in production 'lots'...lot numbers except without any 
numbers :-) ) I believe that are more susceptable to this problem. I'd 
like to get some of the stuff that you can coat on them to rejouvinate 
them but the web sites seem DEAD that sell this stuff.  Fill out the 
form, get a bogus error message.

Anyway on occasion you can remove a tiny amount of the rubber with 
acetone rub down.  It doesn't always work but does sometimes if it's 
just a glazed surface problem.  Other times I'm scaled them down some 
and gotten them working again.  But IN GENERAL you should be able to lay 
probes on them and get below 600 ohms pressing them side by side flat 
ways.  Fine probes of course.  If you get 1000 they are probably going 
to be sporratic or delayed contacts.  If 2000 they probably won't work 
at all.  400 or less is typical for really good ones.

I just got a polysix in that the guy used plastic bags for end padding.  
I kid you not.  I went over it with him but he was in a hurry and just 
did the stupid thing.  Both ends cracked in half.  I'll have to makes 
some oak ends to get the dollar out of that one.  Was a decent unit 
before that happened to it.  But I got it with an analog and digital 
board extra for 330 I think it was and he gave me 50 back for the bungle 
so I should come out good on it. -Bob
Tom Wiltshire wrote:

> The other likely faults on a sick polysix beyond the already- 
> mentioned battery leakage are:
>
> 1) The bank and program switches. These tend to lose their caps and  
> often the switches themselves pack up too.
> 2) The keyboard contacts. These suffer like many cheap rubber-contact  
> keyboards, and repairs are done the same way - careful cleaning and  
> perhaps treatment with one of the products designed for the purpose.
>
> It's amazing how many other weird faults on a polysix can actually be  
> due to battery leakage though - I've seen the sub oscillator  
> disappear, and the PWM only act as PW, for example.
>
> The voice and effects boards actually seem to be pretty reliable, and  
> the power supplies aren't bad either.
>
> Can anyone else think of anything else that I've forgotten?
>
> T.
>
>
> On 15 Jan 2008, at 20:23, Bob Weigel wrote:
>
>> The low C is the same as all other C's.  The HIGH C is full width  
>> and unique.  I only have one in stock and thought it was spoken  for. 
>> -Bob
>>
>> Sean Ellis wrote:
>>
>>> Thanks for all the replies guys! Got quite a few offers but I need  the
>>> lowest C key, it appears the end keys are different to the rest.
>>>
>>> -----Original Message-----
>>> From: synth-diy-bounces at dropmix.xs4all.nl
>>> [mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of Martin  
>>> Pavlas
>>> Sent: Monday, January 14, 2008 9:00 PM
>>> To: synth-diy at dropmix.xs4all.nl
>>> Subject: Re: [sdiy] Polysix keys
>>>
>>> Hi,
>>>
>>> Senso from www.vintageplanet.nl seems to have them. Check that out.
>>>
>>> -- 
>>> martin
>>>
>>>
>>>
>>> Sean Ellis wrote:
>>>
>>>> I am picking up a sick polysix that is missing a key and has some  
>>>> other unknown problems, probably due to battery leakage. Does  
>>>> anyone know a source for a replacement key?
>>>>
>>>> It's great to have Scott Rider's excellent polysix repair page  
>>>> (here: http://www.oldcrows.net/~oldcrow/synth/korg/polysix/ 
>>>> index.html ), looks like I'll be needing it very soon :) Not sure  
>>>> if Scott is on this list but I'm curious about the missing page  
>>>> labeled "Give your Polysix a Korg PS3100-Style Triple resonant  
>>>> filter". Sounds very interesting but the schematics for the  
>>>> Polysix are a nightmare to read.
>>>>
>>>>
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>>>
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