First post, by athlon-power
So, a while back, I decided to try to force a motherboard from an IBM PC 350 Type 6581 with a Intel 486 DX2-66 into a Packard Bell PB400 case, and while it "worked," it had a few issues, which were pointed out to me in the original post. The case underwent extreme modification, and so did the motherboard (well, the riser card did at least), and it also happened to look ugly as sin. Skip forward a few months, and I've worked on it quite a bit and fixed some of the original glaring issues that were there, to try to attempt to make things a little better.
First major fix: the riser card.
In order to fit the riser card from the IBM system into the Packard Bell case, I had to cut 1/3 of it off. Yep, my instructor at my technical school took a diamond grinder wheel to it. Anyways, this left exposed traces and rough edges, which I immediately covered in electrical tape and left there. This, among an uneven cut, made it look genuinely awful, and I also had bent parts of the retaining arm down where it was cut just too short to hold it in place, which also looked awful.
I took the electrical tape off, and sanded down the board until it was as level as I could get it using sandpaper and subsequently inhaling what was likely an incredibly unsafe amount of PCB dust because I did it indoors and didn't wear a mask of any kind like an idiot, and glued over the exposed, albeit rounded and flat edges, with contact glue, and let it dry. It was the closest thing to PCB sealant I could get, so I had to work with what I had. I then ripped off the bent portions of the retaining arm, and took two heatsink clips that were lying around and manually bent them back and forth until they were the right length, and then bent them into 'v's, and put them through the holes in the retaining arm where they then gripped the riser card, preventing it from moving it back and forth entirely. I put masking tape on the clips themselves where they contacted the PCB to prevent shorts. This part took the longest, with me spending a week trying to find ways to prevent the riser from moving both left and right, using multiple ideas and methods, before I finally asked my mom and she suggested I put clips on it.
Second fix: Making the ISA cards not bend when installed. Now, while I didn't actually fix the base problem, I was able to alleviate it by removing the SCSI controller and using an IDE CD-ROM drive instead. The idea here was that now that the SCSI controller was no longer there, I could put the sound card of my choice in the top slot and not worry about it bending. I feel like the sanding down of the riser card helped for some reason as well, but I'm not sure why.
Third and fourth fixes:
When I was modifying the case to make things fit, I realized that the 3.5" HDD bay was right over where the processor socket was on the IBM motherboard, which wasn't a problem until I realized that the 486 I was using had a fairly tall glued-on heatsink attached to it, which caused it to not fit when it was installed. My instructor cut off all of the 3.5" bay, and now it fits perfectly, but of course, I now have no 3.5" HDD bay. What I ended up doing is using a garbage 3D printed 5.25" to 3.5" adapter which looked utterly awful, which I later replaced with a metal 5.25" to 3.5" adapter that originally went to a 1GB Seagate HDD that I got out of a 486 server that had been left outside for months, needless to say the HDD and most of the components inside were dead. Because of the way the adapter fit into the case, it actually still looked pretty bad, so I changed it out with a two-piece solution (one bracket on each side), which looks much better now.
The IDE CD drive I decided to use (or, the only free beige one I had at the time that worked) was a 48x drive- a massive upgrade from the 4x drive, but the problem was that it had "48x MAX," written on the drive's front, which made it obvious that the drive was far outside of that computer's time. A magic eraser later, and the problem no longer existed.
While this isn't perfect, I think it's far better than it was before. This motherboard likely has bad capacitors as I completely cleaned it and it still:
A) Will refuse to work with cache over 256KB, saying the upper chips are bad, when they are known good chips. Does not happen with 128KB of L2.
B) Has an incredibly unstable PS/2 mouse port, which sometimes works, and sometimes doesn't. Have tested multiple mice, still only partial dice. Sometimes it will lock up the whole computer on POST if a mouse is plugged in, sometimes it will give a pointing device error in POST, sometimes it will work just fine at first but in games like DOOM glitch out all over the place after 5 minutes of play, and sometimes it works just fine.
This photo of the outside of it I took a few weeks ago, but everything else other than some adjustments on the CD/floppy drives to make them more centered are the same: