Unmarked 486ISA/VLB mobo (plz help to identify) \ VOGONS

Unmarked 486ISA/VLB mobo (plz help to identify)

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First post, by Helmatt

Posted on 2026-08-17, 15:00

Helmatt Offline

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Greetings!

Currently trying to get back to life some unmarked TriGem (perhaps) 486 ISA/VLB mobo.
The problem is 'black screen' start with any DX4 processor I have, probably due to wrong jumper setup.
BIOS dump looks healthy, all components I use (cpu/video/SIMMs) been tested separately and work fine.

I've done a plenty of search and even found very similar model on theretroweb, but It's jumper layout didnt match to mine.
There are some features I noticed:
- Missing JP4 jumper (placeholder doesnt seem broken);
- 5-pin JP17;
- AWARD bios;

Is there anyone who knows what excaltly is that model?
Maybe it's dead, but I want to find some mobo manual before I decide what to do with it.

Thans in advance <3

Reply 1 of 6, by Helmatt

Posted on 2026-08-17, 15:11

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Helmatt wrote on 2026-08-17, 15:00:

- Missing JP4 jumper (placeholder doesnt seem broken);

Typo: not JP4, JP14, my bad.
Clearly visible on the 3rd picture

Reply 2 of 6, by Intel486dx33

Posted on 2026-08-17, 15:31

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3 pyramids ?

Reply 3 of 6, by BitWrangler

Posted on 2026-08-17, 15:38

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I found this one which looks right, but no jumper info...
https://theretroweb.com/motherboards/s/mitac- … unknown-sis-461

Edit: though I doubt there are jumper settings for a DX4 on that board, looks too early, being socket 2 and there's no regulator. Best you can do without mods or interposers would be a DX2

Unicorn herding operations are proceeding, but all the totes of hens teeth and barrels of rocking horse poop give them plenty of hiding spots.

Reply 4 of 6, by Helmatt

Posted on 2026-08-18, 20:56

Helmatt Offline

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BitWrangler wrote on 2026-08-17, 15:38:

I found this one which looks right, but no jumper info...
https://theretroweb.com/motherboards/s/mitac- … unknown-sis-461

Thank you very much! You set me on right track. This was not TriGem, it was really MiTAC/Trigon, I didnt recognize the logo.
Today I've done some AI search and found enough to make it start on DX4-100.

I'll make jumper setting documentation for the retroweb later on 😀

Reply 5 of 6, by Babasha

Posted on 2026-08-19, 05:33

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Very interesting is research method

Need help? Begin with photo and model of your hardware 😉

Reply 6 of 6, by Helmatt

Posted on 2026-08-19, 07:46

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Babasha wrote on 2026-08-19, 05:33:

Very interesting is research method

Suprisignly, but yeah.

Tbh I'm not a hardware engineer, and I have poor skills of debugging hardware.
I traced PCB paths, wrote detailed text description of chips / jumper locations, made of hi-res photos and used it as a promt for GPT5.6 with web search.
It used all available public data of SIS471 motherboards with jumper descriotion and matched it to mine.

It found the most matching motherboard models by composition:
1. MiTAC QP486SX Rev.B
2. Chicony CH-471B
3. MLE SiS471 Rev.B

Having the info of the most important jumpers I made it start.
There are some jumpers are still unknown to me, trying to discover their meaning

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