I recently picked up this really cool Chips & Technologies 386DX board, which supports both 80287 and 80387. The interesting thing about it is that the two sockets are combined into one really weird amalgam:

I still need to image the BIOS chips from the board, but I did a quick test of it, yesterday, and it powers up, and with a POST card installed, it gets to code 15. That code indicates a problem with the first 64k of RAM, which is not too surprising, since I have no good way to test the 32bit memory board outside of this machine. What IS interesting is that the post code rapidly flashes on my POST card. None of the codes before 15 that go by flash, and I haven’t seen that behavior ever before.

I have already checked all of the voltages, at the P8/P9 connectors, and they are fine. Additionally, I have deoxited the PGA sockets and the ISA connectors.

Here is a link to the page on The Retro Web:
https://theretroweb.com/motherboards/s/magus- … -techn-386-4-20

Does anyone have any thoughts?

Thanks!
- Alex