[sdiy] Yamaha CS80

[Sarth]

Are you sure that's not just an admonition that the footpedals won't work
properly without being connected before power-on? It seems so odd that a
synth could be damaged or even work improperly if powered up without
footpedals connected.

----- Original Message -----
From: <WeAreAs1 at aol.com>
To: <Linc at christeld.freeserve.co.uk>; <synth-diy at dropmix.xs4all.nl>
Sent: Tuesday, March 19, 2002 5:02 PM
Subject: Re: [sdiy] Yamaha CS80


>
> In a message dated 3/19/02 1:17:08 PM, Linc at christeld.freeserve.co.uk
writes:
>
> << I've been given a CS80 for a short while with no footpedals or
> instructions.
> On the front someone has put a label: 'Important, connect footpedals
before
> switching on'. As a bodge can I put a tip-ring shorted quarter inch jack
in
> the footpedal (expression) socket or is there something special about the
> proper pedal? Is it just a potential divider and where can I get one? I
know
> a volume pedal could be rewired but would this give an adequate range from
> nothing to full level?
>
> I'm assuming no sound will come out without the pedal and that no harm
would
> actually occur if it were switched on.
>  >>
>
> The CS-80 (and almost all of Yamaha's pre-1987 instruments) used an
optical
> footpedal.  It contained a photoresistor and a smal incandescent light
bulb.
> The pedal moved a little "curtain" between the light bulb and the
> photoresistor.  I think that one of the three terminals was DC voltage for
> the bulb, the other two were ground and the "wiper" of the photoresistor.
> The early DX7 volume pedals worked pretty much the same way.
Unfortunately,
> I don't have access to the schematics right now, so I can't give any more
> detailed help.  For safety's sake, you probably shouldn't directly short
any
> of those wires to ground (without some sort of current-limiting resistor
in
> series with the short, at least 1K).  Maybe someone who has the schematics
> will chime in here...
>
> Mike B.
>