Yamaha CS80

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!
>
>  
>


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