B850m suddenly dead

The CPU can trigger a power safety and prevent power on yes, if something inside
the CPU has shorted out. If a power safety has triggered for another reason and
not cleared it can also cause the system to not respond to the power switch. You
can try the following to rule that out:

1. Disconnect the system from power
2. Disconnect the PSU from the board
3. Disconnect power from all devices attached to the board
4. Leave the system in this state for a few hours (I usually leave it over night)

Then reassemble and see if the safety has cleared. If not then you can remove
the CPU to check if it has any obvious damage. It looking fine isn't a guarantee
that it's ok but it does rule out a more catastrophic failure. If the
system does not power on once you reinstall the CPU then I would begin the RMA
process for the CPU and possibly the board if it has taken any kind of damage to
the socket.

The known issue is exceedingly rare despite the media over focus. I have only seen
a small number of cases reported here on the ASRock official forums which should
be telling. The upside is, if you are one of the unfortunate few, the process of
getting it sorted should be pretty straight forward and not cause you any headaches
as AMD and ASRock are both taking the issue very seriously.

Good luck and let us know how it goes.


Edited by Xaltar - 5 hours 25 minutes ago at 12:29am

AFAIK the board won't power on without a CPU installed either.