Kawai Synthesizers

Hi Alan
Thank you for your reply,but can you tell me more speciffic which chip or connections and on wich board to look for?Because I'm not technician,but my friend is.I had a problem before,the first 8 keys were not working and I sent e-mail to kawai.They responded and told me exactly wich connection was bad and they sent me scheme of the board,so my friend found it right away and resolder it,so the problem was fixed.
 Please help,if you can
Thank you again
Igor
Alan Probandt <alan_probandt@...> wrote:
   Sensitivity or MIDI note-on velocity is measured by
the time from when the key starts moving from the top
to the bottom of the keystroke. Each key has two
switches.  One opens when the key starts moving down
and the other opens when the key reaches the bottom of
the stroke.  The switches on the keys themselves are
OK or there would only be one or more random keys with
problems, not one in nine.

  There must be a chip that is reading nine keys at a
time and measuring this interval on the one that got
pressed.  On a good key, press it down a little and
find where the logic is changing on the board.  See
where it changes again when that key reaches bottom.
Test again with a bad key.  With a continuity meter,
check if the connection is broken between the leg of
the chip and the trace on the printed circuit board. 
It is either a bad solder joint or a bad chip.  If the
trace shows that switch is working on the bad key and
the pin on the chip that is supposed to be connected
to to that trace shows no activity, then resolder the
connection between the pin and the trace.  Otherwise
try and replace the chip.

  Good luck.

Alan Probandt
Portland, Oregon


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