Yamaha CS80

ok,

So, all keys up until the top D key work fine. If i press a single key  
above top D i get no sound whatsoever BUT if i hold a key below the  
top D key and one above at the same time it will produce the note  
below top D correctly and the note above with lots of distortion and  
the wrong pitch.

If i press 8 keys located below the top D key, all voices work fine so  
i know it's not an issue with a M board.

I have checked the ICs on the lower boards and have found some strange  
behaviour on IC12 of the KAS board (4016). If i measure the voltage  
between ground and pins 8 or 9 while pressing a low key on the  
keyboard, i get a small voltage (1-3 volts) on the meter. If i press a  
key above that D key i get a negative voltage around -4.5 volts. No  
lower key press gives a negative voltage.


Andrew


On 16/07/2011, at 5:19 AM, Quazimodo wrote:

> That don't make sense... can you explain it better Andrew..!
>
> "...unless a key from an octave below it" ...?
>
> --- In yamahacs80@yahoogroups.com, Andrew Kirkby <kirkbyte@...> wrote:
> >
> > I now have another problem on the top octave now - i can't get any
> > sound unless a key from an octave below it, then i get crazy sounds
> > without correct pitch. Looks like a morning on the scope is  
> needed :)
> >
> > AK
> >
>
>
> 

Andrew Kirkby
(e) kirkbyte@...
(m) 0416 000 070






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