<What puzzles me is why the IMSAI folks decided to use a switching power <supply when the box and everything else already supported the needs of the <S-100 with the previously available and now quite inexpensive unregulated <supplies of yesteryear. One of the main benefits of the S-100 was that it It would hae to be regulates at Vreg(oncard)+3V to work. or every cards would ahve to have the regulators ripped off. Add to that +5V bus sag bus (STD, Multibus, Eurocard, Qbus, unibus...) were either physically short or used multiple supplies powering short segments. On a more serious vein, cost, availability and oh UL/CSA/TUV/<your favorite safety/electrical/communications standards agency here>. I should look at this hack to see how much damage there is... likely the idiots have a PC inside wiggling the lights and thats all. Allison