i might be wrong but i think that the 486 cpus tend to have the multiplier circuitry built in, so as long as it's the same FSB and voltage, it will work.

the jumper settings in that manual show the same configuration for a dx 33mhz as well as a dx2 66mhz - so a dx4 100mhz should also use the same settings.

Spitz wrote on 2021-01-23, 08:08:

Guys, […]
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Guys,

I've bought MS 4138 mobo along with DX4 100Mhz cpu - fom now on my consternation started. Refering to the manual:

https://stason.org/TULARC/pc/motherboards/M/M … 86-MS-4138.html

it's stated that it supports only DX2 but seller said that DX4 was correct detected ... any ideas how it's possible?

What's more I've found same mobo over internet showing.... DX2 100mhz? ... And what about required voltage 3.3 - 5 ?

There´s a voltage regulator on your mainboard, so - if jumpered correctly - a DX4 should run with a Vcore of 3.3V.
Your BIOS also identifies it correctly. Maybe there´s a different (earlier) revision of this mainboard on Stasons.

As for the DX2 @ 100 MHz we can only speculate. Maybe it´s running an earlier BIOS that lacks the DX4 ID and identifies a 100 MHz DX4 (or DX4 Overdrive) as DX2.
Or someone managed to oc a DX2 66 to 100 MHz pushing the FSB to 50 MHz 😉

Arrived... Tommorow need to check it out.

If everything is up and running fine, give it some decent VLB graphics.

http://www.win3x.org/uh19/motherboard/show/3617
I have already added the picture. Would love to have a bios dump from the board if you can manage to make one. Also, it is now still listed as being 5V-only but I guess we'll find some more jumper settings on yours.

I will have to convert this into a PDF before uploading to UH19... For now I hope this helps.

Looking at the manual evasive sent, it says it supports DX4.

The manuals on stason.org/TH99/Microhouse Technical Library/win3x.org are imprecise or just wrong and need to be corrected ... Which is what we do on win3x.org 😀
I'm adding the DX4 to the win3x page.

Thanks guys for great info! It's nice to know that You're running win3x.org! I'll try to make BIOS dump, first I need to setup those things today, and convert ATX to AT PSU.

Aftet quick analyse of the manual I've encountered that it is not coresponding to this MB:

- In section cpu type setrings: JC1 for example has 14 pins and my mobo has 20, JC2 in manual 14 pins in mobo has 16

So sadly I think it's not that MB. It's VERY similar at first look, but it's different mobo.

What is more - manual at stason is not ok as well - some differences in pins as well!

Spitz wrote on 2021-01-26, 14:05:

Aftet quick analyse of the manual I've encountered that it is not coresponding to this MB: […]
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Aftet quick analyse of the manual I've encountered that it is not coresponding to this MB:

- In section cpu type setrings: JC1 for example has 14 pins and my mobo has 20, JC2 in manual 14 pins in mobo has 16

So sadly I think it's not that MB. It's VERY similar at first look, but it's different mobo.

What is more - manual at stason is not ok as well - some differences in pins as well!

I think it actually matches, pay a closer look at the pin labeling, MSI boards can be confusing at times. JC1 has 14 pins, JC2 has 16 pins (in the manual as well)

Stason is just another TH99 clone. We at UH19 linked the original MTL manuals directly. This explains why you saw the same "error" on Stason as well.

Still it doesn't match. Look at the manual and mobo again 14 vs 16 pins... there's one more thing:

In manual to set 3.3V on CPU You need to bridge JC2 PIN 1-14 different than signs at mobo PIN 2-15 <---that's how it is now

If you start counting from pin 2, it matches with the printed manual. Have a look at the DX/SX jumper patterns, you'll see that they match.

It is possible the printed manual is based on a earlier/later revision of the PCB, compared to the MTL manual.

Still... same - doesnt match!

My mobo (if agreed with Your pin countage method) is set to 7-8 at JC1 Yes? Refering to the Manual, it should be then a 486 SX/DX CPU!
I don't have SX/DX - I have installed DX4....

it's probably just the difference between Rev.1 and Rev.1.3

here you can find a picture of the original revision (VRM not populated) with the 14pin jumper:
https://computer-retro.de/Bilder/Mainboards/M … mibios-1993.jpg

you can see that the marking on your motherboard for 3.3V CPU has the additional row marked on the board as opposed to the Ver.1 motherboard which only shows 14 pins in the markings.
so it should be the second row then like marked on your board, so according to the picture it should be currently jumpered to 3,3V

the manual probably just refers to Ver.1 and they probably included a seperate piece of paper with the changed jumpers on later revisions as is usual with motherboard manuals from that era.

imi wrote on 2021-01-26, 15:04:

it's probably just the difference between Rev.1 and Rev.1.3 […]
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it's probably just the difference between Rev.1 and Rev.1.3

here you can find a picture of the original revision (VRM not populated) with the 14pin jumper:
https://computer-retro.de/Bilder/Mainboards/M … mibios-1993.jpg

you can see that the marking on your motherboard for 3.3V CPU has the additional row marked on the board as opposed to the Ver.1 motherboard which only shows 14 pins in the markings.
so it should be the second row then like marked on your board, so according to the picture it should be currently jumpered to 3,3V

Bullseye... it's not manual for my 1.3 REV. Thanks imi!

Spitz wrote on 2021-01-26, 15:02:

Still... same - doesnt match!

My mobo (if agreed with Your pin countage method) is set to 7-8 at JC1 Yes? Refering to the Manual, it should be then a 486 SX/DX CPU!
I don't have but SX/DX - I have installed DX4....

It's simple, you need to add the extra jumper on JC2 pin 13&14 and the extra ones on JC1.
It just happens the scanned manual is slightly newer/older than your board, with some minor differences.

(Photo below is an example of how it should be on your board.)

computerguy08 wrote on 2021-01-26, 15:12:

Spitz wrote on 2021-01-26, 15:02:

Still... same - doesnt match!

My mobo (if agreed with Your pin countage method) is set to 7-8 at JC1 Yes? Refering to the Manual, it should be then a 486 SX/DX CPU!
I don't have but SX/DX - I have installed DX4....

It's simple, you need to add the extra jumper on JC2 pin 13&14 and the extra ones on JC1.
It just happens the scanned manual is slightly newer/older than your board, with some minor differences.

Perhaps, but it's working now on Dx4 without placing additional jumpers, what's more the 3.3V pin setup step is telling us clearly that it's not the manual for this mobo, despite the fact of 80-90% similarity of those PCBs

Don't take old manuals for granted, you'll oftenly see things like this.