Hi all. First post here.

I'm resurrecting an old 486 system with a Biostar 1433/50UCV-E mobo. System is unbranded, but it was pretty well tricked out when new, with 4MB ram, 120MB HDD, VLB Floppy/IDE controller, VLB Mach64 Video, and ISA Sound/CD controller. I'd really like to get this beast rolling again.

Problem is that I get no response when I hook up a VGA monitor and power up. HDD spins up and CD door works, but nothing on screen.

I suppose that this could be a video card issue (hopefully not - I don't have a spare VLB video card lying around), but there is one other clue that baffles me. The POWER led does not light up. TURBO switch toggles the TURBO led on/off, but no PWR light. Other than the TURBO led, the only other indication that the board is alive is small 'D5' led on the corner of the board that lights up. Same symptoms when I first pull all three expansion cards.

Should I ignore the unlit POWER led, or is this the smoking gun? Power supply, or mobo?

I have a couple of spare AT power supplies, but they don't have a power switch and I'm not quite sure how to hook one up. Both have just Black/Brown/Blue/White wires with spade connectors. I can't reference my target system for guidance because its power switch leads have been soldered on.

Thanks for any guidance in advance.