B550M Steel Lagend not turning on anymore

Hi.

I'm using a B550M Steel Legend since may and it worked fine. Today I turned it off and tried to turn it back on 1.5h later but nothing happend.

Specs:
* CPU: 5900X
* PSU: BeQuiet Pure Power 11 FM 650W
* RAM: 2x 32GB Mushkin Redline
* GPU: AMD 6650XT

As long as the Mainboard gets power the LEDs are pulsing. When I push the power button nothing happens. No Fan spinning, non of the red status leds light up, no display signal, just nothing, like no button was pressed.

Things I checked
* Switched Power Button for an other Button
* Removed Power and pushed Clear Cmos Button for a couple of seconds
* Unplugged all unecessary cables from the mainboard, only the 2 power cables and power switch connected.
* Checked the board and the PSU (as far as I can see without opening it) for any burn marks or blown condensators but all looks fine. No strange smells.

From my nearly 30 years of building PCs I bet on the mainboard, but I don't have an other PSU on hand to rule out the PSU completly. But from my experience PSUs usually die complete and not partial.

Any other ideas what I could also check?

You can try this:

https://forum.asrock.com/forum_posts.asp?TID=630&title=how-to-clear-cmos-via-battery-removal

If a power safety is stuck on it might clear it and allow the board to power on
again.

Modern PSUs more often than not partially fail these days, either through increasing
ripple or voltage droop as capacitors wear out. PSU manufacturers have done a lot
to mitigate actual blow outs like we used to get, those often caused cascading
damage to other components. As standards and safeties have improved it has become
rare for a quality PSU to suddenly just stop working entirely.

The reason I mention all that is because it can cause power safeties to trigger
on motherboards when ripple exceeds a certain threshold or droop causes voltages
to fall below a certain level. Sometimes these safeties can get "stuck" and even
a new PSU seemingly doesn't solve the issue. Leaving the system disconnected from
power over night after pressing and holding the power button to fully discharge
the capacitors is often all that is needed to revive the board.

If none of that helps, contact the store you bought it from and see if you can
still RMA the board under warranty. If not, contact ASRock and inquire with them:
http://event.asrock.com/tsd.asp

Good luck.

Most boards require a CPU to power on. Good luck

Awesome, glad I could help

It shouldn't be a recurring issue, likely the old PSU tripped a safety. The board
ordinarily should return to normal once a new PSU is installed but sometimes the
safety can get stuck on when the board's capacitors are not fully discharged before
a new PSU is connected. The safeties require the power to be completely drained
from the board before they disengage, it isn't a glitch. Generally the time it
takes to remove a damaged PSU and replace it with a new one is enough time for
this to happen. When it isn't, the steps I listed usually resolve the issue.

Tried the other PSU and connected a speaker to the board. Same behaviour an no beep codes.

CPU looks fine on the outside and no broken pins or burn marks.