The Kawai & Teisco Analog Synths Group

I guess there should be some kind of similarity between the 240 and
210. You might do well trying to use the 240's schematics ;)

An audio probe wil help as well. As I said, already two bad 4066 on
mine, so I won't be surprised at all if you find a bad one on yours as
well...


--- In kawai-teisco@yahoogroups.com, "Travis Shire" <boardjunkie@...>
wrote:
>
> There are sites which sell the service manual. I got the SM for my 240
> from Celedonia Organ Service. Cost me 15$. I doubt getting datasheets on
> chips will do much for you....you need to know how each IC is used
in the
> circuit. Without a schematic you'd likely be chasing your tail.
> 
> 
>   I'm not sure if it's on all the voices; I'll check in the next few
>   days. You're probably right, Gil, about the op amp. AND the need
>   for a schematic. If I can't find one, I guess I'll just make a list
>   of all the ICs on the synth board, google the datasheets, and
>   play 'hunt & peck' with the scope. Luckily, I'm not seriously
>   hobbled without it. I'm really glad that I don't have to depend on a
>   bunch of old, cobbled together gear to gig with, like the old days...
> 
>   --- In kawai-teisco@yahoogroups.com, "gil_we" <gil_we@> wrote:
>   >
>   > My bet is that there's a bad opamp, or another 4xxx chip in the
>   Cutoff
>   > circuit... Does it happen on all voices ?
>   >
>   > I had two bad 4066 in mine, so you might want to check in that
>   > direction. But again, I think you'll need the schematics.
>   >
>   >
>   >
>   >
>   >
>   >
>   >
>   >
>   > --- In kawai-teisco@yahoogroups.com, "jfloydhumanoid"
>   > <capstoneliving@> wrote:
>   > >
>   > > --- In kawai-teisco@yahoogroups.com, "gil_we" <gil_we@> wrote:
>   > > >
>   > > > Can you describe the problem more precisely ?
>   > > >
>   > > >
>   > > >
>   > > > --- In kawai-teisco@yahoogroups.com, "jfloydhumanoid"
>   > > > <capstoneliving@> wrote:
>   > > > >
>   > > > > --- In kawai-teisco@yahoogroups.com, "gil_we" <gil_we@>
>   wrote:
>   > > > > >
>   > > > > > We're still looking for one. The only scans that I managed
>   to
>   > > get
>   > > > > was
>   > > > > > of the main CPU board... (in the Files section)
>   > > > > >
>   > > > > >
>   > > > > >
>   > > > > > --- In kawai-teisco@yahoogroups.com, "jfloydhumanoid"
>   > > > > > <capstoneliving@> wrote:
>   > > > > > >
>   > > > > > > I bought it new in '84, gigged with it a few years, got
>   > > married,
>   > > > > & just
>   > > > > > > dug it out of storage a few months ago. Of course the
>   patch
>   > > > > memory was
>   > > > > > > gone, but amazingly the Ni-Cd battery hadn't leaked. I
>   > > replaced
>   > > > > it,
>   > > > > > > loaded the factory patches, & it fired right up! It's in
>   > > great
>   > > > > shape,
>   > > > > > > except for a sort of 'garbled' artifact in sounds with
>   the
>   > > filter
>   > > > > > > somewhat stopped down. If the filter cutoff is all the
>   way
>   > > open,
>   > > > > it's
>   > > > > > > not present. Anybody have a PDF (or other form) of the
>   > > service
>   > > > > > > manual? I'd be happy to send $ for your trouble...
>   > > > > > >
>   > > > > >
>   > > > > Thanks for looking, Gil... Anybody have any suggestions
>   where I
>   > > > > could point my scope probe & discover the origin of this
>   > > > > unwanted 'distortion'? I'm not afraid to troubleshoot
>   without a
>   > > > > schematic...you can't be timid & repair 'vintage'
>   electronics.
>   > > > > - J -
>   > > > >
>   > > >
>   > > It sounds similar to the 'overdriven' sound of a tube amplifier
>   > > stage, but 'garbled', and not clipped. When the filter is
>   completely
>   > > open, the artifact isn't audible; only when the filter cutoff
>   freq is
>   > > low enough for the heavily 'filtered' sounds. It also has an
>   aspect
>   > > of being periodic (having a set, repetitive pattern), suggestive
>   of
>   > > possibly being a result of some other signal bleeding through,
>   but
>   > > that's purely speculative...
>   > > In the next few days, if it's possible (and allowed) I'll post an
>   MP3
>   > > in the files section. Would that be proper protol in this
>   group? I
>   > > don't have much experience in this area, so please forgive me if
>   > > it 'isn't done'.
>   > >
>   >
> 
>   
> 
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