Hey guys, long story short my brand new z690 (I had it lying around since January 2022) is not powering on. Only turns on briefly If I update the bios using the update through flash function (the CPU fan and all other stuff turns on). After update it shuts off again and won't power on. The Code E6 is shown. The board is EVGA Z690 Classified. CPU 12900K. PSU Corsair 1000W. Otherwise without trying to update, no POST codes are shown. It seems to be a very specific problem, tried to power on without the CPU, just the board and 24pin + EPS 8pin. Nothing. Checked everything (different PSU, cables, "breadboarding" etc), nothing helps.
 
Support suggested to submit the RMA request, but after submiting it - they replied that I should try "changing the CMOS battery". I tried changing it myself but gave up on the idea because it is very low chance of it being the issue.
However the real issue is removing the plastic shroud on top of it, removing 2 screws doesn't help since it seems to also being held from the back side. I tried to remove the backplate (unscrewed all screws) but it seems to be "glued" by the termal pads or something. And I didn't want to apply force in order to avoid voiding the warranty. In the end i still can't reach the back side of it. Great design.
 
Maybe anyone had experience changing the CMOS battery here? I would appreciate any help!
 
Also, decided to do some explanation on the board issue itself cause google search didn't find anything that is close to my problem, just in case anyone had this issue too.