Strange problem. My guess: either the keycoder is putting out wrong
data or the dac is having problems with it note-ladder-network. Maybe
some faulty resistors in the network ?
I can't imagine someone having soldered wrong the wires coming from
the keyboard to the kas-board. But it can't be wrong checking:
solderpoint 25 on the KAS, D# input, must be a yellow wire for
instance.
Good luck !
--- In yamahacs80@yahoogroups.com, David Rogoff <david@...> wrote:
>
> 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
> >
>