[sdiy] Siel opera6 schematics

[Tom Wiltshire]

Damian,

There are Opera6 schematics available somewhere, 'cos I've got a  
copy. Furthermore, the quality is pretty good - way better than some  
of the unreadable rubbish you find online (JX3P?!).
  It's one of the ones I've been looking at whilst thinking about DCOs.
If you don't find it anywhere (or can't be bothered to look), I'll  
send it to you.

To determine whether the synth is repairable, you'd need to know  
which ICs have been removed. The design has 8253 counter-based DCOs,  
followed by SSM2044 filter and SSM2024 quad VCA, controlled by a  
SSM2056 Envelope generator per voice. It's very similar to the Korg  
Polysix (except that had VCOs) or the Poly61.

If someone thought the synth wasn't a viable repair, they might well  
have removed the valuable SSMs to sell. You could probably cover the  
cost of the synth like that. The SSM2044 filters are still available,  
but the envelope generators might be hard to find. Alternatively,  
find a dead Polysix (not hard - they die all the time) that hasn't  
been stripped and use that for parts.

Regards,
Tom

On 17 Dec 2008, at 13:17, damsagain at free.fr wrote:

> Hi everybody,
>
> I was searching a vintage Siel Opera 6 Analogic synthesizer when I  
> found an ad
> about it but the seller said to me that I would have to restore it.
> Indeed he told me that integrated circuits missed on his Opera 6.
> So I have a question :
> - Does Siel Opera 6 schematics exist ?
> I search on the web but I found nothing.
>
> However I wonder :  Does it a good idea trying to fix that  
> synthesizer while I
> don't really know why IC have been removed ?
>
> :-/
> Thank you for your interest.
> Best regards,
> Damien
>
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