PC Hoarder Patrol wrote on 2024-05-18, 13:35:

jnemo2004 wrote on 2024-05-18, 06:59:

Hello!, good morning.
I would like to find any info about this motherboard: OP3486H
Thank you and regards.

Don't see it on The Retro Web (might be worth submitting here https://theretroweb.com/info/contributions ), but possibly this from The PC Engineers Reference Book...

Unknown (OP)3486.jpg

Hello good morning. Here are some photos of the motherboard. I know they are not of very good quality but I don't have a better camera. In a few days I will remove the ICs that are in socket to wash the board and then I will dump the BIOS and leave it here as well. Please post the photos of the board on The Retro Web as I do not have the experience to do so.
Thank you so much

Perhaps Opti's Local Bus, seeing the chipset is theirs. Not much standard back then.

(I recall a friend imported some local bus mobos + local bus video cards from the same chinese company, and then they didn't work together.
When he asked about it, he just got a 'sorry, hope it's not a problem for you' from the guys...last purchase made there.)

jnemo2004 wrote on 2024-05-19, 08:12:

PC Hoarder Patrol wrote on 2024-05-18, 13:35:

jnemo2004 wrote on 2024-05-18, 06:59:

Hello!, good morning.
I would like to find any info about this motherboard: OP3486H
Thank you and regards.

Don't see it on The Retro Web (might be worth submitting here https://theretroweb.com/info/contributions ), but possibly this from The PC Engineers Reference Book...

Unknown (OP)3486.jpg

Hello good morning. Here are some photos of the motherboard. I know they are not of very good quality but I don't have a better camera. In a few days I will remove the ICs that are in socket to wash the board and then I will dump the BIOS and leave it here as well. Please post the photos of the board on The Retro Web as I do not have the experience to do so.
Thank you so much

Thanks for the pics...as requested I'll pass them on to the RTW team for inclusion though, after a more detailed check, it would appear your board is already there - https://theretroweb.com/motherboards/s/zida-opti-3486

PC Hoarder Patrol wrote on 2024-05-20, 07:18:

jnemo2004 wrote on 2024-05-19, 08:12:

PC Hoarder Patrol wrote on 2024-05-18, 13:35:

Don't see it on The Retro Web (might be worth submitting here https://theretroweb.com/info/contributions ), but possibly this from The PC Engineers Reference Book...

Unknown (OP)3486.jpg

Hello good morning. Here are some photos of the motherboard. I know they are not of very good quality but I don't have a better camera. In a few days I will remove the ICs that are in socket to wash the board and then I will dump the BIOS and leave it here as well. Please post the photos of the board on The Retro Web as I do not have the experience to do so.
Thank you so much

Thanks for the pics...as requested I'll pass them on to the RTW team for inclusion though, after a more detailed check, it would appear your board is already there - https://theretroweb.com/motherboards/s/zida-opti-3486

Thank you very, very much.

Hello, here you have the BIOS dump.
Regards.

About the math coprocessor 3C87-40
Is it correctly mounted in the socket? I believe, it is not.
Thank you

https://www.cpu-world.com/CPUs/80387/IIT-3C87-25.html

I'd expect that pin 1 would be indicated with the little corner stud, by the sticker. And the silkscreen on bottom right matches the PGA holder, so you may be right that it is misaligned - maybe broken, if powered on in that position...try to verify comparing locations of the ground pins perhaps?

I didn´t happen very often, but when I happened to insert a 5V CPU the wrong way it shorted the 5V rail so the PSU wouldn´t start.
It wouuldn´t surprise me if the same goes for FPUs.