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 ...

Linksys Wireless G Range extender, b & g.<BR>Model WRE54G. google is your friend.<BR>Extender, corded plug, wall plug, install cd and box. Changed routers at home, new one takes the big hawking ...