Here's an old thread that might give some insight to your confusion.
http://chipmusic.org/forums/topic/6698/
lp-please/
Here's an old thread that might give some insight to future confusion.
http://chipmusic.org/forums/topic/7615/
ch-thread/
Ok, I've broken a pin when trying to swap it, so:
I thought about vcc through USB. Will then the ground on the DMG have to be connected to the ground of the keyboard and the ground of the USB?
Couldn't you just try the pin swap again with the other half of the spliced DMG04 cable rather then bringing a usb in the mix?