Per TRW it looks like that board has an Award 4.50G BIOS, which should support LBA and would have no business not supporting a 1.6GB drive. So it wouldn't be that.

You can try cleaning the edge connector on the ISA card with a pencil eraser to clean off any dirt/corrosion layer. You could also try moving it to another slot in case it is a mechanical issue with that slot on the motherboard. Also, try a different ribbon cable. Temporarily, disable external cache in the BIOS as flaky cache can cause all sorts of issues (but, probably not this one).

Don't bother with a caching controller especially if you're going to run Windows 95. If you were going to change this out for anything you would want a VLB Multi I/O card instead of ISA.

It has to be a hardware problem of one form or another. ISA IDE cards are very simple, and a 1.6GB drive would have been tested thoroughly with them.

Before buying more HDDs, you might consider a CompactFlash card and adapter. Sometimes those require some tinkering of their own though. Plucking certain IDE pins for better CF-IDE compatibility

Haha, "486 headache" - that pretty much sums up this hobby when you are dealing with machines from that era 🤣

My knowledge of isa IDE controllers is pretty limited, however I'm pretty sure that if you wanted one that would be better you would be looking for one that uses the VLB slot

As for CD roms - more often then not I see these go undetected by 486 bioses so that's not unusual at all, but usually my windows 98 boot floppy will detect them regardless (not sure on 95 but I don't think much changed). I have had a few systems where they were unusually picky on which CD rom that would work with though, using the oldest one I have handy for installation fixed that (for me) after which windows had no problem detecting/using a more modern one

So basically I could try installing ms dos from floppies and then try installing cdrom drivers?

You should try swapping everything. Another ISA Slot, another Controller, another ribbon cable, another HDD or CF, another ODD. Also configure the BIOS to the slowest timings and write-Through Cache or Cache disable. Try a Win98 boot floppy. It should Detect IDE ODD and you can Partition/Format your HDD or CF with it. Also check if your ODD is real IDE and not something propietary like Panasonic or Mitsumi interface. Good Luck.

The CD drive is slave to the HDD?

sunkindly wrote on 2025-10-16, 19:34:

The CD drive is slave to the HDD?

yes

Retronerd878 wrote on 2025-10-16, 15:43:

I’m putting together my first 486 build, and it’s been quite a challenge. The motherboard is a SOYO 025N2, and the CPU is an Int […]
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I’m putting together my first 486 build, and it’s been quite a challenge. The motherboard is a SOYO 025N2, and the CPU is an Intel 486 DX4-100 WB. Since the board doesn’t have an onboard IDE controller, I’m using an ISA IDE card (photo attached).

The hard drive is a 1.6 GB Fujitsu. When I try to manually enter the cylinders and sectors, the system won’t get past POST. If I use the BIOS auto-detect feature, it gives me three configuration options — none of which are correct — but if I select one, the system does go past POST and begins booting.

I’ve connected a floppy drive, a hard drive, and a CD-ROM drive (set as master/slave). The floppy is detected, and the hard drive also appears in the device table before boot. When I insert a Windows 95 boot floppy, it boots fine but reports that no drives are detected and exits. The CD ROM is definitely not detected. I don't know if it refers to the hard drive as well.

Questions:

1. Am I using a hard drive that’s too large for this system?
2. Would buying a newer or more advanced IDE controller make things easier?
3. I’ve seen IDE controllers with onboard cache — would that noticeably improve performance? (I’m considering 1.5–2 GB drives.)

Or is my current IDE controller fine, and I’m just missing something? Any help would be greatly appreciated!

I had same board with a dX2 long time ago, i have a 32GB CF card without trouble, just use ezdrive 9.03 or 9.06, dont relay on bios, believe me, is better a overlay

Then use uram to gain UMB, you will need for drivers

Does BIOS have a Type 47? This typically allows you to manually set the heads, cylinders, and other hard drive geometry to match the ones on the hard drive label.

I agree with the above about trying different cables, Hard drives, I/O controllers if you have any.
To start with I'd remove the CD drive altogether in case its conflicting with something .

Drive overlay is a good "cheat" way as well, as you can use just set it as a 40MB drive and have the software do the rest.
https://youtu.be/8LzCB6kDVC8?si=rH8v5xqsLKj63v4p

486 BIOS won't mention the CD drive at all but your Windows boot disk should pick it up. The good news is just about any drive should work, even a DVD or Burner if that's all you have. 486 won't be able to make best use of em but still an option

I tried using a larger 8.4 GB drive, but it wasn’t detected, so I switched back to the Fujitsu. I used another rig with SpinRite to check the HDD for bad sectors — but at first, the drive wasn’t detected. Turned out the master/slave jumper was in the wrong spot: it was all the way to the right, when it should’ve been on the opposite side.

The drive has six jumper pins and no clear labeling, but after tracing the PCB I found some markings elsewhere. Once corrected, SpinRite detected the HDD and confirmed it was healthy.

After that, the BIOS detected the drive correctly, though the CD-ROM still wasn’t recognized. After swapping a few CDROM drives, I finally found one my controller was happy with.

Currently installing Windows 95 — looks like everything’s finally coming together!

Nice. Sounds like it was an issue with jumpers. You may put a VLB I/O card on your wish-list though as it would be faster.

Good detective work.
While painful at the time, the challenge of getting these old systems working is what gives more satisfaction after it's completed.