Hey there,

I fairly new to the retro PC game. I worked in a computer storeat the end of the 90s and know some things. Already had my shot with Amigas 😉
But now I got my hands back on old pc Hardware having fun tinkering again. Among other things in real life I develop open source PCBs and sell them through my small company. So some tools regarding electronics work are present.

Got my hands on a Chaintech 6VTA2 Board, incluning a Pentium III 500: https://theretroweb.com/motherboards/s/chaintech-ct-6vta2
The sticker on the BIOS chip cleary states it's a 6VTA2 albeit the board looks more like an 6VTA3 (https://theretroweb.com/motherboards/s/chaintech-ct-6vta3).
It is scratched a little as I had to read the chip type - see photos.

So, I wanted to update the BIOS using the files from the retroweb. Installed was the 07/07/99 version and I tried to update to 12/18/2000 using awd899.exe. The board worked withought any problem before in Win98SE and (free)DOS.
I backuped the existing bios beforehand and flashed the new one. Only when I restarted the machine I saw that there were some blocks with write fails (red). But i was too late.
After a reboot the mainboard is stuck at a black screen. Currently no pc speaker attached, so I don't know if it is beeping. Most likely it is...

Well, I thought, no worries and dug my TL866II MiniPro out, blanked the MX29F00NT-12 (120ns) and wrote the backup I made before.
But no luck... still a black screen. Maybe the flash chip is done? There were no errors on verify on the MiniPro...
Then I tried the newest BIOS from retroweb, also no luck.

So, I ordered some AT27C020-90PU (90ns) which should be compatible, are they?
Burned the backup, burned the newest .bin - no luck.

As you see I'm stuck and would be very happy if someone can point me in a direction to fix this. Obviously I understand something wrong.
Should I try the minipro on real Windows hardware? Currently using it on Win11 ARM on my M1 MacBook in UTM (https://github.com/utmapp/UTM).

Cheers and thank you,
p