Successfully Upgraded 286 to 486

[seaken]

Successfully Upgraded 286 to 486

I had been trying to repair an old MicroLab 286 that had battery damage on the motherboard. I made some progress cleaning it up but I ended up hitting a wall with my skill level and I abandoned that motherboard. So, I was looking at what I could do to replace the motherboard and get this old MicroLab computer working.

A couple weeks ago I found an old 486 in a large tower, about 25" high. I was tearing it down and cleaning it and getting ready for testing. I looked at the motherboard and I wondered if it would fit in the MicroLab case. I certainly didn't need this huge 25" tower and thought it would be better to put it in a the smaller desktop case. I tried fitting it and it fit fine. The power connector was a little hard to access and the SIMM chips were also blocked. But I could get at them by removing the power supply.

So, the final result is that I upgraded the old MicroLab 286 to a 486. This 486 board is a VLB type. It has five ISA slots and three VLB slots. The CPU is in a socket 3 and is a 486-DX4 running at 100Mhz. This makes this "MicroLab 486" my best in class 486.

I have three other 486 machines but I have never had a VLB motherboard. And my other 486's are slower speeds (one 486-33, two 486DX2-66).

The machine came with this 486 VLB board and the 486DX4-100 and 32GB of RAM. The boards were a VLB VGA card, a VLB Multi-I/O controller for the floppy, hard drive, and serial, parrallel and game ports. There was also an ISA CD-ROM card and an attached CD-ROM drive. The other cards were an ISA modem card and a second ISA Serial/Parallel card.

There were two hard drives, a 3.5" and a 5.25" floppy. When I reassembled everything into the MicroLab desktop case I ended up with the two floppy drives, a single 500 MB IDE hard drive, and the CD-ROM. The power supply in the 25" tower did not work. But I was able to use the power supply from the MicroLab case.

My only concern is whether the 486DX4-100 could overheat in the smaller desktop case. There was a lot more breathing room in the 25" tall tower. The heatsink does have a fan on it. We'll have to see how it goes.

So, my failed MicroLab 286 project turned into a MicroLab 486 success.

Here's my log for this upgraded MicroLab 486:

Sean's Old Computers

486 VLB upgrade to MicroLab Case I was unsuccessful with the MicroLab 286 motherboard. But I tested putting this 486 VLB motherboard in th...

seansoldcomputers.blogspot.com

Seaken

 

[seaken]

Some pics

Pulled 486 VLB motherboard from huge tower


The motherboard ready to go into other case


The motherboard fit to MicroLab desktop case


The power supply blocks easy access to power connector and memory chips


Testing. The MicroLab power supply worked. VGA and floppy works.


Thanks for looking
Seaken

 

[twolazy]

That tower case should fetch a good price on ebay if you are wishing to not use it.

Btw you should be fine. My dell 486 w/ 586 was in that same size case for years. Dont worry bout it getting too hot, if so just throw on a fan behind the front faceplate or get a slot based exhaust fan. I wouldn't worry about it personally.

 

[seaken]

Yes, I may do that. I haven't decided yet what to do with it. I may use it in my other room. I just wanted to keep the MicroLab case in my main lab because it stacks well and I am in the process of redoing my DOS wall. The tall tower doesn't fit in the new space.

Seaken

 

[mR_Slug]

Second on the tower case, that is real nice. The DX4 should work fine in that small case.

 

[Caluser2000]

Good work.

This is what I did on my first x86 system-a clone 286/16. First upgrade was to a second hand 486/mobo then some years later a Socket7/SS7 mobo with Pentium 200mmx fitted.

 

[seaken]

Thank you. I am happy how it turned out. But truth be told, I was hoping for a 286 success story. (I still have a chance with another 286 - just need a controller in that one). I had never used a VLB system before so I will be happy experimenting with the 486DX4-100.

I am thinking of installing DOS 5.0 and Win95, and maybe OS/2 2.11. I have a similar setup on another 486DX2-66 using System Commander for multi-booting. I am wondering if this 486DX4-100 will run W95 better. I'll give it a shot. But currently there is no sound card and I am out of ISA Ethernet cards. I may steal some stuff from my FreeDOS 486 system.

Seaken