Hmm, IMSAI's didn't have ROMs (or PALs and FPGAs, programmable logic had yet to be invented), unless you added them in yourself. As for checking the power supply, an IMSAI was extremely easy to eyeball...huge transformer, diodes, and beer can size capacitors. One problem I never had with IMSAIs was in the power supply, the design was right out of Electronics 101, nothing beats a big lump of iron for simplicity. Now rust might be a problem... Actually, the only real problem I've ever found with S-100s is the bus connectors wearing out. I have an old Ithaca Intersystems DPS-1 in need of a replacement Morrow motherboard. Well, not really in a hurry to fix it, all the Ithaca boards have been in the IMSAI for the last 10 years, but I hate to throw out the DPS-1 since it had the neat front panel with the PDP style toggle switches. Jack Peacock