Question 3900X on asrock Fatal1ty X470 motherboard not entering BIOS or boot menu

[Willy--]

I recently upgraded from a 2700X to to 3900X on a Asrock Fatal1ty motherboard. It is dual boot to Ubuntu and Win10.

After I installed the new CPU I could occasionally (twice in about 20 attempts) get the F2 or F11 to get me into BIOS or boot menus. If left to get through to GRUB it would boot up Ubuntu or Windows fine.

I updated the BIOS to 4.3.0 hoping to fix the BIOS issue but have not been able to get into the BIOS again. Also while GRUB is in it's 10s timeout period if I touch the keyboard the counter stops and the system locks up. If left alone it will boot Ubuntu and it seems to run fine. If I reinstall the 2700X it all works fine. Tried a BIOS reset and that had no effect. Error code on DrDebug is A9 for quite a while then changes to 0C.

The next plan of attack is to reinstall the 2700X and change GRUB over to boot to Win10 by default so I can run the MB tuning software and see if I can see what is happening. Not sure what else to do, already tried removing/unplugging most of the rest of the system without any good effects.

Any ideas on why it will not enter the BIOS?

Cheers,
Willy

 

[rgd1101]

check cpu temp?

 

[Willy--]

CPU never got over 55C while it was running Ubuntu. Also doesn't seem to perform any different when turned on cold, or after having been running for hours. Normally the CPUs will get as far as BIOS without the heatsink on when cold started so I was thinking CPU temp wasn't an issue (though I can't really check the CPU temp while its in POST as I can't access anything). Fans/etc are all working, nice thin even layer of thermal paste on the CPU.