well . . . back when dinosaurs roamed the earth, and IMSAI was a major computer maker, the 25.2VCT was about as common as its companion, the 6.3V filament heater (starting to sound familiar?) and there were a few supplies which got away with that. If you filtered well and used only one diode at a time, you still had enough headroom to allow for 2.2 forward volts in the regulator. I've got switchers in the basement which have adjustable voltages for three (5-10Vdc, +/-12-18Vdc). The previous statement that switchers like a constant load is quite correct, though and what is meant there is that the switchers don't like capacitive loading, nor do they like loads which are intermittently on. S-100 boxes sometimes housed floppy and hard drives, though, and if it was only the 5-1/4" types, and floppies only, the +12 saw its worst nightmare. It saw nearly fully on, vs nearly fully off, since one floppy took more +12 than all the RS232 ports. I don't know where they're going to end up, but I believe that the power supply thing will have toox have quite a bit more attention than it's gotten so far. My advice to anyone wishing to sell hardware in the quantities they're likely to sell, would be to build a kit, no assembled units, find a catalog standard switcher to sell them, and use the fact that it's all just spare parts to bypass the FCC reg's. Sell the box top, sell the box bottom, the front, the rear, but no fully assembled boxes. Sell the front panel as a replacement part, too. That way there's no enclosure to require approval. What's more, it will make the phone support burden lighter. If they want a fully assembled and tested unit, tell them to buy a PC. Dick -----Original Message----- From: Allison J Parent <allisonp(a)world.std.com> To: Discussion re-collecting of classic computers <classiccmp(a)u.washington.edu> Date: Tuesday, August 17, 1999 8:00 PM Subject: Re: imsai 2