This is the closest to mine as I could find - SIS 486-471. It has support for numerous of processors, AMD among them. I find that rather good news as the old processor was in fact AMD 486 DX4. This is the only model with the similar configuration.
The only difference is that the 70-pin slots are on the inner side of the board. This is with all the 471 models with this chipset.
The other clue I noticed is that I have only 38 jumpers. And the most manuals for 471 state to close either JP41 or JP42.
SIS 486-471 manual has 38 jumpers as well, so tomorrow I will try the new config and let you know.
If someone here does now what the motherboard is, please do let me know.
There is a picture of it in the upper comments.
Thanks

Ironically the one Sis 85C471 motherboard that I have stopped working. I took it out of its anti-static bag today and it behaves like you describe: no boot, no image and no beeps 🙁 It was working fine last time I tried it, which was around mid-2007. Bummer.

Any luck with yours, or is it really dead?

Well,
I managed to burn some resistors 😀))). The jumper settings seems to be incorrect, so I gave up. I bought a nice 486 laptop with VGA output, so I am happy now (Toshiba T2100).
At the end of January I will buy a UMC MB457 Socket 3 Motherboard + U5SX 486-25/33 GREEN CPU + 12 Mb RAM fully operational and configured 😁.
Then everything will be fine.
I also bought OEM Pentium II machine - Dell OptiPlex G1 (GX1) for 15 euro 😀). Very good condition and working perfectly. So it has been a nice month.

Marry Christmas and Happy New year 😁