andy120 wrote on 2024-08-14, 19:56:

I have 3 486's with FDD and HDD issues. UM and SIS based chipsets + a super I/O chip i think it is. What chip/s are best bet to replace to obtain FDD/DE functionality back? The BIOS can see them but thats all. I have tried a pci and isa I/O card, but it cannot use those either.

Andy

I'd first make sure the PSU is in good condition. This is very important as AT PSUs are old and can have dry capacitors. Then, the cables. Once you have one PSU that works fine with one set of cables on one motherboard, then you can be sure that the problem is with the other motherboards.

Have you disabled the on-board controller when you try to use an ISA controller card?

About ISA controller cards, in my experience they are all more or less the same, but there may be compatibility issues with some particular combinations. If you can use a VLB or PCI controller card for your hard drive that would be faster. It can be IDE or you can also go SCSI.

hi. tried everything i can think of. used different power supply, primary secondary and card, plus cf and spinning disks formated on a pentium 1. the bios sees and id's it right, just wont read it.
andy

"I have a broken car, which part should I replace to repair it?"

We need waaaayyy more info really.

what size HDD did you format on the pentium? Under 500MB?