Be sure to look at my upcoming contest mod for LCD replacement of the CRT on a G3 iMac. I'll be posting the mod in a few days. I'm not sure if the power supply situation is exactly similar, but there are different ways of addressing the 20 V thing. On the iMac I found that it was adequate to supply +15V to it because +15V is more than adequate for powering FireWire ports by tech specs.. most FireWire products only need 12V. The iMac has a particular problem though of not having a -15V supply (if memory serves) that it needs for balancing the other half of the op amps used for driving the audio circuitry. +30V could be used to obtain -15V by centertapping a transformer with floating common to output + and - 15 each side, but for some reason I recall, it didn't work, so i wasn't able to solve the audio problem just yet.