Howdy,

the procedure is pretty much the same as all PCM systems, if that is
what you have.

1) remove back
2) locate the big long chips
3) run the keyboard and touch different parts of the circuit board with
your finger. Use drum patterns, sequences, etc. Most Casios, if you
extend certain wires such as battery power and possibly speaker
(although I just remove the speaker with wiring intact), you can fold
the PCB out from under the unit and have it laying down behind the unit.
4) When you touch something that makes a difference in speed or pitch,
use a small metal jewelers screwdriver t ofind the exact points that
cause the change. Mark them with a small "p" with a sharpie. These wil
be your clock controls.
5) The big long chips(usually off to one side), you can take a very
fine peice a wire, 30 gauge pin wrap wire is perfect, and start
shorting out the pin connections. Soldering a small (10 ohms or so)
resistor will help if you are afraid of shorting something out. Start
with one pin and touch each individual pine of the chips. write down
what happens.
6) If the unit ceases to work, turn it off and then back on to reset
it. Sometimes you might have to remove a battery for a "hard" reset.
7) solder a normally closed push button in series with one of the
battery leads so you can reset by merely pushing the button.
8) After you have done this, reveiw your list of what pins effect what
other pins in ways that you like.
9) Carefully solder a 30 gauge wire from each pin, through a single
pole switch. You may want to use double ploe as you can get 2 responses
from 1 switch on occasion.
10) Mount the switches in the keyboard itself or run to an external box.
11) where you found the "clok" point, wire the middle tab of a pot and
find another point to solder one the outside tab of the pot to vary
clock speed. If you hunt around enough, you may find a point to slow it
and another point to speed it up.
12) Buy Reed Ghazala's book and the book "Handmade Electronic Music" by
nicholas Collins so you can see actual pictures and different
procedures to expand your knowledge.
Rig

-- In CasioSK@yahoogroups.com, "eliotclayton" <eulett@...> wrote:
>
> Hi everyone.
>
> I was recently given a Casiotone 501 professional keyboard that was
going to be thrown
> away (gasp...) Has anyone out there had a chance to mod one of
these??
>
> I cant help but think the potential is there.
>
> Just curious.
>
> Thanks,
>
> E.
>