Yamaha CS80

skkatter wrote:
> Hello! I'm one of the new members mentioned a while ago. :)
>
> I just bought a Yamaha CS60, which according to the seller was in
> great working condition, but upon arrival it is exhibiting a problem.
> Perhaps somebody has come across this before or could guide me on what
> to check?
>
> Basically some of the keys are playing incorrect notes. On each
> octave, when I press c, c#, d, f#, g, g# they all play fine.
>
> However when I play the other notes they do the following:
>
> I press d#, I hear a c#
> I press e, I hear a c#
> press f, I hear a d
> press a, I hear a g
> press a#, I hear a g
> press b I hear a g#
>   
Ok, this is strange.  First, look at the KAS chip spec 
(http://www.therogoffs.com/cs80/manuals/CS60_Service_Manual/06%20-%20KAS%20ICs.jpg).

Note  N4N3N2N1  Note heard
C     0001      Good
C#    1111      Good
D     1110      Good
D#    1101      1111 - N2 stuck @ 1
E     1011      1111 - N3 stuck @ 1
F     1010      1110 - N3 stuck @ 1
F#    1001      Good
G     0111      Good
G#    0110      Good
A     0101      0111 - N2 stuck @ 1
A#    0011      0111 - N3 stuck @ 1
B     0010      0110 - N3 stuck @ 1

I don't see anything obvious. Anyone else?
Have an Oscilloscope? A spare KAS chip :^)

 David
> All the notes are perfectly "in tune", but exactly half of them are
> playing the wrong note. This happens for all octaves, each wrong note
> is in the same octave as the other notes (ie when I press f3 I hear a
> d3, when I press f4 I hear a d4).
>
> The seller assured me it was working fine when it left him, and he
> tuned it before it left. It travelled via a courier company from Paris
> to Berlin so perhaps something has moved around a bit inside (the
> seller seems genuine so I believe that it left his place in working
> order).
>
> This is my first Yamaha CS synth so don't know much about them (for
> example, how do you open up the front panel? :)) I do own a multimeter
> and would be willing to measure voltages to find the source of the
> problem. Has anybody come across a fault like this before, or knows
> what I could check?
>
> One other thing which may be worth nothing, according to the seller, a
> French technician called Jean-Loup Dierstein has installed a simple
> little kit inside the CS60 which tells you via 8 leds which voice you
> are playing when you press a key. (this might come in handy!) I can
> hold 8 keys down (ones which play different sounding notes anyway) and
> hear 8 notes at the same time .
>
> So, what to check next? (thanks in advance)
>
> -Stephen
>