Kawai Synthesizers

Hello,

  I have never worked on a synth keyboard but I am
very interested in learning them.  I am an electronics
technician with experience in microcontrollers and
programming.
  If you have the K1 schematic in digital form, such
as a PDF file or GIF file, you could attach it to an
e-mail message.  With the schematic I might be able to
suggest which chips to examine.  If the schematic is
on paper and you have a scanner, then I suggest
scanning it at 300 dots-per-inch, 2-color (Black and
White only, not grey scale) and saving the scan as a
GIF (not JPG) file.  That makes a very detailed, but
compact, file of the schematic.
  I hope that I can be of more help.

Alan Probandt
Portland, Oregon USA

--- igor nikolovski <pianoigor@...> wrote:

> 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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