possibly a dead CMOS battery?
possibly a dead CMOS battery?
If this were my setup, the following would be my next step would be to switch to a different PSU.
Verify your Power button using an ohm meter if available, with the computer unplugged and wires removed from the motherboard header "power switch wires". You'll need three hands: one for each wire, with another hand pressing the power button. Observe the meter readings; if they increase, the switch functions correctly. Alternatively, you can jumper the power switch pins on the motherboard header using a small flathead screwdriver, ensuring proper contact and good lighting throughout. Also confirm that your new battery is making full contact with the prongs. If everything works as expected, proceed to the power supply.
I just removed the GPU and attempted to jump the pins, but nothing happened. I also checked the RAM.
EDIT:
But recently, before it failed under load, I heard an unusual electrical noise from the PSU.
Hey there...
When a device produces an odd sound, it’s probably trying to communicate with you.
Try using a tester power supply on the system. If it works, maybe it just needed assistance before reaching this stage.