Are you sure that the CD-ROM is actually IDE? There were at least three different pre-IDE "standards" and two of them (IIRC) had the same connector as IDE. If you can find SoundBlaster 16 MCD, that one had all three interfaces. It may be cheaper and easier to use different CD drive anyway.

I'm quite sure, as the drive is just a re-branded LG GCD-R542B drive. Plus the soundcard has four interfaces (IDE, Panasonic, Mitsumi, and Sony). Plus I don't know of any Panasonic or MItsumi interface drives that have a master/slave jumper.

I see. On-card IDE controllers could be very picky, you should have better chances with motherboard controller. Did you check IDE configuration in BIOS? Old AMI BIOS was not PnP, you had to manually specify the drive, sometimes force it to rescan from BIOS. Some drives just refused to work as slave devices. Other than that -- check if the drive actually works in another computer. Also, try different IDE cable (make sure it is 40-wire version, not the newer 80-wire).
The motherboard looks quite typical for late 486 era. Unfortunately, that was a time of great instability 😉 so I would not trust PCI slots to work correctly. OTOH, the IDE controller is fairly standard UMC part.

Actually it's the other way round. Back in the day very few IDE CD ROM drives would work as master and they have been set default to slave since they were brought onto the market. Also, I've never heard of PCI slot 'instability' even in the crappiest of crap ALI chipsets. The only time PCI fails in 486 generation machines is when it's overclocked too far from 33mhz - then it can lead to instability and even slot/device burn outs.

ALi was fairly compatible and stable but not much better (or worse) than the rest. When I said "instability" I was talking more about the market, constantly changing specs, etc. It was quite common then to buy a new card and find that it does not work in some slot or with some other cards -- certain sound cards were known to do funny stuff with the bus. Many ISA/PCI motherboards had known issues with "shared" slot. 486 boards with PCI had their own set of quirks. On the positive side, they had more robust I/O hardware, not like the original ISA MIO cards that tended to die all the time.
As for CD-ROMs working better as master or slave -- hard to tell now. The first batches had to be configured as slaves, there was no choice on many boards. At the time when that particular board was made (ca 1996) the situation was already changing and there was another variable -- hard drive PIO level support. So, it's not that CD-ROM did not work as slave at all, it just did not work well with some hard drive and settings. In many cases it could be fixed by playing with BIOS but I had at least one case when I had to physically rearrange drives.

NightSprinter wrote:

Unfortunately I cannot get it to recognize the 4x CD-ROM that came with it (regardless of whether I use the board's IDE ports or the built-in one on the Reveal K2Y-PRO16 card that came with the machine).

Let's try to fix this first... What exactly do you mean with 'recognize'? The CD-ROM drive does not show up anywhere at bootup or in the BIOS setup? This is perfectly normal on 486 and early Pentium machines, as their IDE controllers weren't ATAPI compliant and couldn't boot from CD-ROM. A connected CDROM drive will not show up until you load the drivers.

A few hints:
- Forget about the soundcard or other add-in cards (too much stuff to go wrong). Use the IDE ports on the mainboard.
- Check and re-check the IDE cable connection between the board and the drive. Old boards and drives don't have plastic guides around the connector pins, it's awfully easy to plug the cable the wrong way around or missing a whole pin row, especially when many connectors are cramped in a small area.
- Jumper the CDROM as master and hook it up as a single drive. IDE specs were not well-defined back in the days, so often two drives refused to work together on the same IDE channel.
- If it still doesn't work, try a newer CDROM drive.

About early PCI boards:
All 486 and first-generation Pentium PCI chipsets were buggy in some way. The Intel Saturn chipset needed three revisions until it was useable without crashing, and the other chipsets were not much better. Common problems were busmastering and burst-mode timing, most boards were "fixed" by simply turning these features off, resulting in lame performance. Typical PCI cards at that time had incomplete configuration space entries or did not decode addresses correctly.
Another 486-specific problem was the bus speed: Pentium systems (up to SuperSocket 7) simply halved the FSB, resulting in PCI clocks of 25, 30 or 33 MHz, all within spec. On 486 board designs the host and PCI clock rate was the same, which could be as low as 16 MHz and reach up to 50 MHz. Popular AMD chips (DX2-80, DX4-120) had a 40 MHz host clock, which caused instabilities on the PCI bus.
A common buyer advice in the mid-nineties: Forget about Pentium and PCI, get a DX4 with VLB instead. This was valid until 1996/1997, when the second-generation Pentium chipsets (i430FX/HX/VX) became mainstream.

I've never used a ALI M1487 board myself, but it is reputed to be one of the better 486 chipsets. Unlike the others, it supports PCI 2.1, and it was late on the market, so it may have fewer PCI quirks.

What I meant was that the BIOS does not show a CD-ROM drive connected, regardless of whether it it set to master or slave, single drive or conected to another. Only my 408MB harddrive shows in the list.

This was using the IDE ports on the board, and having disabled the card's IDE port via jumper. I have checked the connections, since the board does label pins 1, 2, 39, and 40 on the board. The cables stripe are lined up with the pin 1/2 side.

Tried a 56x drive with no luck.

NightSprinter wrote:

What I meant was that the BIOS does not show a CD-ROM drive connected, regardless of whether it it set to master or slave, single drive or conected to another. Only my 408MB harddrive shows in the list.

Like I mentioned earlier, this is normal. 486-era BIOSes don't list anything when a CD-ROM drive (or any other ATAPI device, like an internal ZIP drive) is connected. It's also not possible to boot from a CD-ROM.

If you don't have an OS installed, get one of these Bootdisks (make sure you download one with CDROM support). I'm sure your CD-ROM will work just fine once the drivers are loaded.

There was a bad cable. Plus, thread can be closed for now. The BIOS won't detect the drive, but the driver loads it just fine. Dunno how I did it, but it's working so far. 😁 I'll ask a mod to re-open it if trouble flares up again.