View Full Version : Compuadd Help

October 9th, 2006, 08:04 AM
I have a really big Compuadd machine that puzzles me greatly. I haven't gotten it to work yet and Google didn't help any. It appears to be a full size AT machine since I've never seen a PSU or mobo that big before. O_O
What gets me though is it looks like its has dual processor abilities. I only saw 2 empty sockts, but after removing the mobo from the case, I find the first (?) processor was under a drive bay. Its a 486DX-33. But the markings on the mobo look as if there is a second processor socket waiting another 486dx-33. Both sockets are identical in every way. So there are 3 sockets, 2 for processors (??) and a smaller one for something else? This board also has an enormous about of RAM sockets, 16 sockets in 3 banks. Banks 1-2 are together, bank 3 is off by its self. Its got 8 ISA slots too.

So my questions are:

1. Is this thing REALLY dual processor or is that something else?
2. Why so many RAM sockets?
3. Whats the smaller socket for?

This is by far the most intresting machine I've come across. If it CAN take 2 processors, I'm sure I have another identical 486 somewhere. :rolleyes:

Pictures coming soon....


October 9th, 2006, 08:23 AM
Is the existing 486 chip a 486SX? If so, the other socket would be for a 486DX as an up grade.

In ye old days, the 486SX would come soldered onto the motherboard and you would by a special version of the 486DX chip to go in an empty socket. The special version was slightly different than a normal 486DX in that it had an extra pin (or maybe more) that would disable the existing onboard chip.

If you have a 486SX and it is soldered this would make sense. If it is a 486DX and it is socketed, well, maybe somebody did an upgrade by replacing the original 486SX chip instead of adding the correct 486 overdrive.

I doubt that it is a true dual processor motherboard. The 486 wasn't designed with multi-processors in mind, and 486 motherboards that did support it were rare and had lots of 'glue logic' to maintain cache coherency between the processors. And without special OS support, it would be wasted hardware. (Intel fixed those shortcomings with the Pentium.)

October 9th, 2006, 08:37 AM
There's 2 sockets. One has a 486DX and the other is empty. Plus the smaller one. I'll be posting pics soon.

In the main board pic, you can see the 2 sockets with gold squares in the middle. Those are the processor sockets. The one at the top has the 486DX and one on the bottom is the empty one. Then the small one between. Also RAM banks 0-2 are between the ISA slots and sockets. Bank 3 is the one at the top.

The second pic is just a shot of one of the Processor sockets. In this case, the "second" one. Both are identical though.


October 9th, 2006, 08:47 AM
Darn, no VLB slot! chuckle.

October 9th, 2006, 08:51 AM
I can't even find a year. All of the info thats printed on the case and mobo is pretty cryptic. It doesn't say much beyond revision numbers and its serial.

VLB would have been nifty though.


EDIT: Mobo says copyright 1992. Missed that....

October 9th, 2006, 08:53 AM
I had a few compuadd laptops once upon a time, but I've never seen a mobo like that one. I know they were big into point-of-sale stuff, maybe a server or something for the POS stuff?

Mo idea about the triple chip thing. :?:

October 9th, 2006, 09:04 AM
Its far too big to be POS related I'd think. I know nothing of its history and its original drives are gone, I just got its case, and mobo. I don't even know if its even capable of running. I'm going to try though. I may have taken rails for drives, but the rails are long gone too. As far as I can tell, its just a really big desktop.


October 9th, 2006, 09:27 AM
Rails? Who needs rails? I just put down a few hardback books, set the drive on the books with the cables running everywhere and voila! You should see me with my full sized tower moving Windows partitions around on about 4 drives. My stupid computers all use different drive geometries, as I found out after wasting hours. They wouldn't even boot properly on the new machine (240 vs 255 heads) I kept forgetting about that over and over as I attempted to move the drives between machines. The Compaqs gave me NO ACCESS to the drive parms so I was S.O.L. I had to copy each partition, file by file instead.

October 9th, 2006, 09:28 AM
I think it is one of the early multi cpu systems. It would take either a 386DX, 486SX (and optional 487) or 486DX (any ONE of these depending on jumper settings).

The 386 would go in the smaller socket. The 486sx would go in one of the bigger sockets. The 487 would populate the others if you were using a 486SX. Or you would just put a 486DX in there.

Here is a link to a couple of similar boards:

The 4 SIMM sockets by themselves are probably for additional Cache. The other 12 sockets probably hold 1 or 4 meg SIMMS for a total of up to 48MB.

Just my $0.02.


October 9th, 2006, 09:36 AM
There is no processor soldered to the mobo, just those sockets. In reference to the pic, the top one has a 486DX-33, what would I add to the other sockets? I have 386DX's and probably another 486DX-33 if I can find it. I'm just a little confuesed now. O_o


October 9th, 2006, 09:52 AM
There wouldn't be ANY processor soldered to the MB in what I'm trying to describe. It was just a very good multipurpose motherboard. It would allow for the user to buy a really good motherboard, and then upgrade CPU as finances allowed. Low end, it would support a 386/20. High end would be a 486dx2/66.


for a VERY SIMILAR board.

October 9th, 2006, 09:58 AM
email sent

October 9th, 2006, 10:27 AM
Ok, to my great suprise, it acutally booted and functions when I truned it on. More suprisingly is that I have its OS floppies. 2 different ones. I have Windows 3.0 and Windows 3.1, both from Compuadd. Thanks for the help everyone, I'll keep ya posted.


October 9th, 2006, 10:57 AM
Wow! What a great mobo! Booo hoooo, I'm jealous now :shock:

Terry Yager
October 9th, 2006, 11:32 AM
As Mike pointed out, the close-up is definately an OverDrive socket. Note the 'extra' pin on the inside upper right-hand corner. I'm also going with the 386/486/OD upgradable board theory, hence the three sockets. Judging by the location of the extra SIMM sockets, I'd guess that they are for extra cache.