Need identifying this Motherboard (486DX4 rev.A04)

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Need identifying this Motherboard (486DX4 rev.A04)

Post by noname_user »

Hello. Nedd manual for this mobo. The model name is DX4rev.A04.
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Re: Need identifying this Motherboard (486DX4 rev.A04)

Post by evasive »

Thank you for putting in the picture.

Are there any other markings on the board anywhere?
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Re: Need identifying this Motherboard (486DX4 rev.A04)

Post by noname_user »

Yes. There is.
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Re: Need identifying this Motherboard (486DX4 rev.A04)

Post by evasive »

Hmmm not was I was hoping for. I have so far checked between 50-100 boards with a sis471 chipset, not one is matching your layout.

The bios chip may give up some secrets but for that there needs to be a CPU, memory and a VGA card in the board so it can boot until the bios screen. For the CPU to go in there we need to know how to set the jumpers. For that we need to know what board it is and a manual. Catch 22.

Unless, you have a way to read out the bios chip, either from an EPROM programmer or another motherboard (the hotflash method). For that you need to have another board that is using the same size/voltage eprom chip...
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Re: Need identifying this Motherboard (486DX4 rev.A04)

Post by evasive »

OMG.

I decided to check my ancient collection of favorites. Because there was this Japanese website with pictures of motherboards...

Well...
http://home.att.ne.jp/alpha/pcboard/0439NN.jpg

Bang, 100% match.

0439
:CMC
:486DX4
:REV .A01
:SIS
:85C407
:85C471

So much for the good news. We know the make is CMC and the model is actually 486DX4.

The bad news is, even back in the day it was extremely difficult to find info on this company. I found a reseller in Norway that was guarding the info like a golden egg or something (REC computers). Nothing else. So now, 15 years later, this is a challenge. But I've surprised myself before,
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Re: Need identifying this Motherboard (486DX4 rev.A04)

Post by evasive »

Ok so REC was owned by Cinet who went bankrupt in 2003. They were bought by Itegra AS (from Sweden?) so that is the next stop. Good old-fashioned info-hunting.
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Re: Need identifying this Motherboard (486DX4 rev.A04)

Post by Dozer »

Hi,

I have this exact motherboard, but no manual. However, I have it working, with a cpu. This means we can get some more info from it.

I have an AMD 486 DX2 66MHz in the computer, but it is performing rather poorly. It registers as 66MHz, but it performs slower than 486 DX33 https://imgur.com/6GkdVlg
Bootscreen is like this
(for some reason, images didn't work, so edited that...)

https://imgur.com/CfFdv76

AmiBIOS, CMCDX4 VLPG-E05

ID: 40-P908-001608-00101111-072594-SIS471G-U

As you have seen from the previous pictures, there are quite a few jumpers. My board is configured for 128k cache.

Now, the 072594-SIS471G-U actually has a match. http://www.elhvb.com/webhq/specs.htm gives us MS-4138 / 486SI5 Motherboard, but the images of that board does not match ours

So, any software I should run to get more info ?
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Re: Need identifying this Motherboard (486DX4 rev.A04)

Post by evasive »

Right, the bios screen is showing a little "i" in the processor name, which leads me to believe the board is actually set for an Intel 486DX2-66 instead of an AMD one.

P908-001608 are for revision P908 and manufacturer ID 1608 = CMC
By taking those out you will get matches on boards from other manufacturers that have been using the same chips from SiS to build their own boards.

Now then. Right now the board appears to be set for the wrong CPU. I just pray there are ANY marjings at all somewhere near the jumpers. JPxx etc. If we are really lucky there are some tables on the board that tell something about those JPxx settings. If not, Could you make detail pictures of the jumpers. There is a remote chance this board has been filed somewhere including setting but just under "unknown manufacturer"/"unknown board". By matching the layout we just might... Maybe.

One other route is: in what system is the board, any brand name, anything known where it was sold, that sometimes gives surprising results.
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Re: Need identifying this Motherboard (486DX4 rev.A04)

Post by Dozer »

So, I did another image. Unfortunately, I cannot get a clear image of the text around the jumpers, so .. this might help:

https://imgur.com/a/sIclaoz

This motherboard was just given to me, out of any box .. "Here, a 486 mother board I had lying around" was more or less the deal :) So, sorry, can't give any more info on that (and the person I got it from, can't remember).
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Re: Need identifying this Motherboard (486DX4 rev.A04)

Post by evasive »

hmmm, my Norwegian is non-existant:
https://snl.no/Cinet
https://www.digi.no/artikler/itegra-bad ... net/301696
https://www.cw.no/artikkel/fortsatt-norske-pc

I don't know where to contact people, even less if they are speaking English or not. Could you try and find someone that might tell if there is any documentation left for the machines REC was making? I know this is a long shot, but as far as I can tell and find, REC was the only retailer to ever use CMC motherboards.
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