[sdiy] Polysix keys

GRAHAM ATKINS gatkins at blueyonder.co.uk
Wed Jan 16 19:20:02 CET 2008 

I can recall at some time in the past being able to buy conductive  
rubber contacts as a sheet that
could be cut to size to suit any application. That might be ideal if  
nothing else works but sadly I can't
remember seeing any recently, but thats not to say there may be some  
out there.

Graham
On Jan 16, 2008, at 4:18, Bob Weigel wrote:

> 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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