[sdiy] Korg Poly61 a peculiar design!!

[Paul Burns]

I take the contacts out with plastic  tools rather than damage them with
metal...plastic chopsticks , plastic flat blade...

On occasion I have rebuilt the traces bridging with wire ... it depends how
badly the nicad corroded/exploded before it was removed ... .. I have done
about five or six... each one different depending the way it was stood when
the battery leaked ...sometimes a small amount of drilling of the pcb
involved ...

The rubber pads were available but I have not bought any recently ... but
the old ones are easily cleaned, as are the contacts...

A good example ...

 http://www.oldcrows.net/~oldcrow/synth/korg/polysix/keyclean2.html


Regards

Paul

From: synth-diy-bounces at dropmix.xs4all.nl
[mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of Paul Cunningham
Sent: 07 April 2011 22:25
To: synth-diy at dropmix.xs4all.nl
Subject: Re: [sdiy] Korg Poly61 a peculiar design!!

Repairing the keyboard is relatively easy if you take your time to
completely disassemble it. The trickiest part is removing the conductive
rubber contacts without tearing them. Does anyone have a good approach to
this? I usually use a tiny philips and push the tabs back through to the
other side.

How do you repair the traces? I've seen one P61 where only solder was
used... That looked a bit tedious though.... Is there a better way?

I'm still in the "completely redesign the motherboard camp" for now. It
doesn't really look like it would be too hard. Dealing with voltage
differences between arduino and this board would seem to be the only hurdle.
The rest is multiplexing a (higher resolution) DAC and clocking as far as I
can tell. I presume its possible to get rid of at least 50% of the existing
electronics if you are going to redesign the control panel anyways. At
current prices, why not have two analog boards?

-pc

On Apr 7, 2011, at 4:42 PM, "Paul Burns" <paul at fitvideo.co.uk> wrote:

> Is the keyboard totally dead , or just partially ? They can be resurrected
> with a bit of TLC...I have done so with a number and also rebuilt the
> damaged traces from the nicad corrosion ...
>
> Regards
>
> Paul
>
> From: synth-diy-bounces at dropmix.xs4all.nl
> [mailto:synth-diy-bounces at dropmix.xs4all.nl] On Behalf Of
m.bareille at free.fr
> Sent: 07 April 2011 17:48
> To: synth-diy at dropmix.xs4all.nl
> Subject: Re: [sdiy] Korg Poly61 a peculiar design!!
>
> Hi
>
> I have a Poly61 too but with a dead keyboard. The keyboard is the true
weak
> point of this synth, and there is no MIDI(sic)
>
> I had +/- in mind to design a special MIDI interface for it to emulate the
> keyboard.
>
> To rebuild /hack the cpu board seem to be a lot of work to do anyway , but
> nothing impossible , just time consumming.
>
> A programmer like my MCV32 ( or like) could probably do the job to manages
> CVs
> and extra panels pot. I have adapted this board to replace the CPU into
many
> RSF
> PolyKobold who are much morecomplex devices  , so it should work on a
Poly61
> ,
> but this will not replace the keyboard anyway.
>
> I am interested  by a readable schematic , at least to help me to decide
> what
> todo with this synth who is taking dust here since many years ...
>
> Thanks,
>
> Marc B.
>
>
>
>
>>
>> I do have some actual paper on this model,  if anybody wants it.  I'd
have
> to
>> dig a bit to be sure of exactly what I have,  though...
>>
>>> KD
>>> --- Den ons 2011-04-06 skrev Tom Wiltshire <tom at electricdruid.net>:
>>>
>>>> Have you got a link to some decent
>>>> schematics for the Poly 61, Karl?
>>>>
>>>> I've got a service manual PDF for it, but it's more-or-less
>>>> unreadable.
>>>>
>>>> Thanks,
>>>> Tom
>>
>>
>> --
>> Member of the toughest, meanest, deadliest, most unrelenting -- and
>> ablest -- form of life in this section of space,  a critter that can
>> be killed but can't be tamed.  --Robert A. Heinlein, "The Puppet Masters"
>> -
>> Information is more dangerous than cannon to a society ruled by lies.
> --James
>> M Dakin
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