I bought a nice looking Promise VLB EIDE controller for my 486 project.

I installed it on to the motherboard, powered on and suddenly one of tantalum capacitors literally exploded.

The capacitor sits between +12V line and GND on the ISA part of the card. The 12V line then continues to the Winbond W83758P chip on the ISA side of the board. I guess it is a filtering cap for +12V power line.

Anyway, despite the bang the card appears still to be working. At least as far as I could briefly tested it.

I was wondering what could be broken on the card and how exactly the +12V line is used on a multi-IO card? I was actually a surprised to see there is +12V (and even -12V) power line used on the card.

Should I be bothered replacing the capacitor? There are 5 more such caps on the board? Would you expect them to be exploding as well any time soon 😀 ?