After destroying the switch on my kiddie casio yesterday, and replacing it, the darn thing still had trouble functioning, so I cut lots of wires and re-did a lot of them. I'm not sure precisely what happened after that, but I've got a nice little burn on my finger now. I think that I managed to set up a short-circuit that channeled most of the battery power right back into the batteries. Oi.
I still can't get the darn thing to work, but I'm starting to really dislike that particular toy, and it may be too screwed up to work with anyhow at this point. *chews on plastic casing thoughtfully*
The next keyboard has pretty much the same circuitry, but it's much tighter (the first keyboard was chunky and oversized, about 11X17. This one's a narrow little strip, maybe 10X5 or so, if not smaller.
I guess I just overreached. I tried to include EVERYTHING that could possibly work. This time, I'm just going to limit myself to 1) a few small connections that 2) don't reach outside the actual keyboard. I'm thinking if I confined myself to two 1mg pots (dials) and two push-button connectors, and a handful of body contacts (points where skin contact is sufficient to change the musical tune) that'll be sufficient.
It's such a small keyboard, it'd be sexier if it didn't need a "breakout box" to house its controls. But the batteries sit right against the circuitboard, and there's v-e-r-y little front panel that doesn't have text all over it.