Considering the SK-1 shares the same CPU as the SK-5 & SK-8, it could
most probably be fixed with a ROM hack. Problem is, of course, no
deompiler is available for the OKI CPU used by the SK's, and the
company have never bothered to respond to any requests I have made,
bastards.

I got to a certain point with revese engineering specific areas of the
SK code....I did this by f'king with specific areas of code (they are
seperated in ROM) and then seeing what part of the SK this would mess
up. I did this over and over again until I'd identified a good deal of
the code (envelopes, preset rhythms/melody, sample looping points etc.)

However, & a BIG however it is, bytes make little sense without a
decompiler it's hard to get predictable results with trial and
error.......

So many projects, so little time

cya

ryan

--- In CasioSK@yahoogroups.com, "gmeredith1" <gmeredith1@...> wrote:
>
> I have been doing some testing and some research about this, and
> have come to the conclusion that it is not possible to do this.
>
> I have sought to bypass the APO signal line from the SK's processor
> and connect an external 5V supply to the power circuit transistors
> to keep the keyboard awake. I thought that this would do it, and now
> the rest of the keyboard does stay powered up, but the processor
> itself actually shuts itself down after 7 mins. The lights stay on,
> but nobody's home. The keyboard will not operate.
>
> Referring to the service manual, you can basically work out what
> i've done. But I believe the processor itself has a timer in it that
> is hard-wired internally in the chip that shuts itself off, no
> matter what else goes on in the keyboard. That's a damn shame, I
> really thought I was on to something.
>
> I can pretty much assume that all other casio keyboards with the APO
> feature will operate in the same way. I have a Casio DG20 digital
> guitar which I tried it on, and it does the same thing.
>
> There IS one way that you can work around this feature, and that is
> to press any button or key on the keyboard every 6 or so minutes,
> before the APO switches off. Knowing this, it should be able to make
> a small timer circuit with a tiny relay or electronic switch that is
> hotwired to some relatively unused function button on the keyboard,
> that will do this automatically.
>
> Anyone have anything to add to this?
>
> Cheers, Graham
>