[AH] AW: cs-50

[Larry P. Torre]

I've got a CS-50 that also makes a high whine, although possibly at lower
volume than described here. It isn't through the audio output though, and
I've always assumed it was from the power supply. The beastie works fine,
and the faint high-pitched whine has not been a problem as I often use
headphones in the studio. The whine does not start immediately upon power-up
but within a minute or so. Also, I get a faint smell within a few minutes
which smells like "warm circuitry" (the CS-50 is packed with analogue
circuitry compared to today's computer-based modules/keyboards).
 Got mine for $120 five years ago in a Seattle mom & pop organ store!

Anyone know if Kenton or somebody currently makes a midi retro-fit for this
synth?

-----Original Message-----
From: Haible Juergen <Juergen.Haible at nbgm.siemens.de>
To: s9610068 at chelt.ac.uk <s9610068 at chelt.ac.uk>
Cc: DIY <synth-diy at mailhost.bpa.nl>; analogue <analogue at hyperreal.org>
Date: December 09, 1998 10:27 AM
Subject: [AH] AW: cs-50


> >I recently purchased a Yamaha CS-50 for £40 (uk sterling). A
>bargain?
>
>Absolutely. I'd pay that price for a completely non-working
>(but physically intact) one without hesitation. (I'd even pay that
>for the mere keyboard action, if it's mint condition ...)
>
> >The only problem with it is that a high pitched noise starts after
>about
> >15 minutes of switching on. It is independent of the volume
>controls,
> >and sounds the same as when pressing the highest key with the sine
>wave
> >an octave up. I assume somehow this setting is shorting to the
>output.
> >Does anyone have any ideas before I take a look inside? It makes
>some
> >great sounds but it's getting really annoying.
>
>Hmm, I'm quite bad on repair stuff (modifying is much more my
>deal), but anyway, a few guesses:
>
>You don't have the Ring Modulator on all the time ?
>("Off" means that the Modulation Slider is UP, not down !!)
>The 15 minute delay is strange, though ...
>Your Ring modulator sliders might have an intermittent contact ...
>Does the pitch change, if you alter the ring modulator frequency ?
>
>If it's not the Ring mod, it might be one of the voices. Does the pitch
>change if you play a four-fingered chord in the lower range ?
>If so, the VCA might leak. If not, you would have a leaking VCA
>*and* a stuck pitch CV or bad VCO at the same time. Not
>likely, but possible ...
>
>That's all that comes to mind at the moment. Next step should
>be a careful inspection of the interior, loose wires, conductive
>objects stuck between the boards, that stuff.
>
>If you have to trace the error thru the circuit, Yamaha still sell service
>manuals.
>
>Good luck !
>
>JH.
>
>