Now the proper vintage and obscure hardware. One Acer 486 motherboard with a lot of integration an a eurocard interface for VGA. Cant find a single reference to the PC that this MB was part of.
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It has 2 sockets for 486, maybe for DX or SX, and a co-processor for Weitek 4167.
Also an ECS FX-3000, a 386/486 motherboard with a nice cpu and co-processor combo:
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Next a Late 486 motherboard from Mitac, the PH4500A, Isa+PCI+VLB:
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Last but not the least, a beast of a motherboard from Fortron, the NetSet 486 EISA:
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It is obscure as it gets. The only info to track the brand was the uncommon bios post, that refers the model as being "NetSet Computer". It was made by Fortron, and the company is still around, now making the good quality PSU, but from 1991, I can only find a few ads from magazines. It does boot, but I have noticed some instability that I have tracked to IC U91, it needs re-flow on a couple of pins.