I think that I might have the same problem. My keybed acts funny from the top key down to the C#. It will trigger, somewhat strange noises, if I have another key pressed in a lower octave. Is this the same problem? How did you troubleshoot it and fix it?
-Mike
--- In yamahacs80@yahoogroups.com, "tmoravan" <moravanskyt@...> wrote:
>
> I originally reported a problem w. my CS80 in that the top octave of keys wasn't triggering any sound. I had some good suggestions from various techs and I verified that the actual keybed was sending the correct voltages from all keys.
>
> The testing and debugging centered around the KAS board. After carefully measuring the values for various keypresses up and down the keyboard, I came to the conclusion that the YM26600 was creating and assigning the right codes, but the YM26700 IC was not working properly.
>
> Thanks to the kindness of a listmember, I popped in a replacement YM26700 and now I have the full range of keys again.
>