IBM ps/2 P70 Plasma screen voltages

Thomas> Well, I'm an electronics student at the university of Twente Thomas> in Holland. I got the board from a fellow student, who Thomas> didn't know what to do with it. The screen runs on 25Mhz, Thomas> reading 4 bits of pixel data at a time. Almost half of the Thomas> connector pins are ground, and the others are default vga Thomas> signal pins. It shouldn't be too hard to get some of the Thomas> pixels to light, I'd really like to know if it still works. Thomas> I don't think i have the DC-DC converter (if it's not on the Thomas> picture), but I can build a new power supply if I know the Thomas> voltages as they are coming from the DC-DC converter. Btw, Thomas> if you have any pictures i'd love to see them. Too bad yours Thomas> isn't working anymore, it's such a cool device :-) I only know plasma panels from earlier days, when they were applied by their original inventor to the terminals of the PLATO system. Those were orange color, on/off only (no grayscale, or "orange scale" I suppose). The power for those panels was quite complex and fairly critical. It wasn't a DC voltage at all, but rather a high voltage AC square wave called the "sustainer voltage". The voltage was chosen so that a pixel, once lit, would stay lit (the sustainer would "sustain" the discharge) but pixels that were off would stay off. You could then turn pixels on or off by pulsing X and Y wires either in phase (turn on) or opposite phase (turn off) -- just like coincident current addressing in core memories. So those plasma panels had inherent memory, no refresh needed. I don't know how far the panel you're looking at differs from those PLATO panels. paul