I'd guess you are looking at a cap failure in the original PSU. 386 era is what, early 90s. 30+ years is a good run. If a replacement PSU doesn't have a switch, you could always hook it to a surge ...

I'm looking to build out my storage box a bit with a bunch of old 1TB drives and a 16 port SATA RAID card (3Ware/LSI 9650SE-16ML) I have lying around. My server motherboard has 8x SATA 3 ports which ...

Switch-mode power supplies are ubiquitous. Standard off-the-shelf modules in a consistent range of form factors available from multiple manufacturers. Globalized manufacturing and trade has turned ...