Okay, here's what I did just now. I took the "new" cable and swapped the green and white wires on just one side - we'll call that side A, while side B has the original wire order.
When I plug side B into the pcb (black wire toward the top of the keyboard, red toward the bottom) and side A into the USB header adapter cable, I get nothing. No message, no sound.
When I swap the cable, side A is now in the pcb upside down (red wire toward the top of th ekeyboard, black toward the bottom), side B is in the USB adapter cable. Error message.
In both cases, I lined up the red and black wires from the header cable with the wires on the header socket first, then flipped it and got the opposite result from what I wrote down.
Thus, to make the error message appear while having all the wires match up, I have to plug the new cable into the pcb with the red wire toward the north end of the keyboard, and then match up the red wires along all connections. If I reverse it at any point, it does nothing - just like my old cable. Weird thing is, my old cable should be the standard, since it actually came plugged into the keyboard, and it only plugs in one way - red toward the south of the keyboard, which produces no sound or message.
So after reading all that, I figured I could get the old error message to appear with my old cable by connecting the usb adapter cable backward - red to black and black to red. Indeed it did. It seems that if I try to match up all the power wires they way they're supposed to go, nothing happens, and if I reverse them at any point, I get an error message.
Note that I also get a disconnection sound effect when I unplug the keyboard, after getting the initial error message. Probably doesn't matter.
I don't know which pin on the pcb is ground and which is vcc, but if I had to assume by the fact that the included ribbon cable only plugs in one way, with the red on the bottom, I'd guess that vcc is on the bottom. But, the keyboard only produces a response when I swap vcc and gnd, and is dead otherwise.
I also tried (still using the original cable plugged in with red wire down) to swap the data wires around in every combination and the only one that produced a response was when the cable was left as-is, but plugged backward into the usb header.
Note: there's an LED that is supposed to turn on when the keyboard gets power. I haven't seen it come on since the time I tried to straighten the pins on the usb connector and it flashed on and off intermittently as I wiggled the USB around in the connector. The light does not turn on when I get an error message from windows. I don't know if that means it isn't getting any power, or if the light doesn't come on until it is fully recognized and connected to windows.
