Yes it does sound like it is a bad IG00158 waveshaper chip. I have them if you need one.
Doug
synthparts.com
--- In yamahacs80@yahoogroups.com, Bob Stewart <bob@...> wrote:
>
> Sounds like you have a faulty waveshaper on channel one. I don't have the
> service info in front of me so can't guide you through it.
> If you're confident opening it up, I'd remove the M card for that voice
> from the frame and put a scope on the triangle out of the waveshaper
> chip and see if you're getting anything.
> If you are, trace the signal with the aid of the schematic up to the switch
> and so on to see where it disappears.
> AT fault with either be a faulty sensor, or a faulty chip. Again if your
> confident opening it up, I'd trace the AT signal from the key sensor, and
> trace it back.
> If you're not sure about opening it up, get someone who knows CS series to
> have a look. These are sensitive machines, so you have to show a bit of
> respect when poking around.
>
> Hope that helps.
>
> On Tuesday, May 21, 2013, pyjamagroove wrote:
>
> > ∗∗
> >
> >
> > Hello,
> > This is my first post here so - Hello everybody! My name is Tobias and
> > last weekend I fulfilled my long time dream of getting (and actually
> > playing for the first time) a Yamaha cs80. Unfortunately initial deep tests
> > revealed two flaws of my machine - I have no aftertouch on middle G key and
> > no sawtooth wave on voice1 card (channel 1). There are noise and square so
> > I don't think it's a VCO or VCF or VCA chip. On the other cards at all
> > channels everything seems to work fine. Anybody have an idea what it might
> > be? Thanks in advance!
> >
> >
> >
>
>
> [Non-text portions of this message have been removed]
>