anunnak wrote on 2026-01-09, 17:12:

Hello and happy new year! […]
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Hello and happy new year!

I recently bought a https://theretroweb.com/motherboards/s/tyan-s1682d-tahoe-ii and when i tried to power it up i get 5 1 4F and 50 51 errors. What i have tried until now:

1. Replaced RAM
2.Ran in single CPU config
3. Reset BIOS
4. Replaced RTC bat

Not sure what else i can do. If anyone has any ideas or experienced this issue before pls let me know what might i try next. These erros are usualy related to memory and i am afraid i got a DOA and the memory controller is defective 🙁

Thanks!

Reflash the bios? Maybe bitrot happened, provided you have an external programmer.

Post HQ pics.

I will try to find someone who has one and see if re-write the BIOS can solve the issue. Thanks for the suggestion. I have attached 2 pics, one from above and one with the bios chip.

anunnak wrote on 2026-01-09, 17:48:

I will try to find someone who has one and see if re-write the BIOS can solve the issue. Thanks for the suggestion. I have attached 2 pics, one from above and one with the bios chip.

Do you have another P-II mobo? Try its BIOS chip as a test with one cpu, if it works with some minimum ram.

I'm taking for granted that cpus, ram, rtc are known working parts.
Is the rtc socket connected to the board? no "no contact" pins.

Nexxen wrote on 2026-01-09, 18:48:

Do you have another P-II mobo? Try its BIOS chip as a test with one cpu, if it works with some minimum ram. […]
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anunnak wrote on 2026-01-09, 17:48:

I will try to find someone who has one and see if re-write the BIOS can solve the issue. Thanks for the suggestion. I have attached 2 pics, one from above and one with the bios chip.

Do you have another P-II mobo? Try its BIOS chip as a test with one cpu, if it works with some minimum ram.

I'm taking for granted that cpus, ram, rtc are known working parts.
Is the rtc socket connected to the board? no "no contact" pins.

HI! Un update:

I moved the board around my workshop and I can't remember doing anything to it other then checking it with a magnifying glass. Tried one more time to start it and out of the blue, it posted. Do not know how but it posted and now i am thinking it might have a slightly detached chip or something somewhere but i have not managed to identify where the issue is.

I tried next to install an OS with the folowing results:

1. Win ME, freezes at the final stage when it is configuring the desktop and such.
2. Windows 2000 installs but when has to enter desktop it resets the PC. Probably too new?
3. Windows NT 4.0 installs and i can get to desktop.

Guess i have to check the board more.