The CPU fans briefly activate after flipping the power button on the PSU, but the PC fails to start.
The CPU fans briefly activate after flipping the power button on the PSU, but the PC fails to start.
Hello, encountering an odd problem that seems unfamiliar. I tried to use my PC last night without any issues, turned it off, and went to sleep. The next morning I powered on the UPS, but the PSU emitted a clicking sound—two clicks, one for power, another for protection. Even without pressing the power button, the RAM lights up and the fans spin briefly as soon as the PSU receives power. The PC doesn’t boot, and neither did the monitors: holding the power button had no effect, the RAM RGB stayed active, and the fans didn’t turn on at all. When I flipped the switch off, the PSU clicked consistently, then when I turned it back on I noticed the fans stopped spinning entirely. I attempted several fixes—reinstalling RAM, reseating it without a GPU, removing the PSU cable to the CPU, and even trying to boot directly from the wall—but nothing worked. After taking out the PSU, I used the included tester with my Seasonic box; the fans only spun when connected to the tester or jumper. I’m really stuck, especially since I just returned from a month-long vacation and want to dive back into gaming. My system specs are: Seasonic GX 750 (replaced a faulty ASUS TUF Bronze 750W), 3060ti 32GB DDR4 3200MHz RAM, i7-12700F, 1 SATA SSD, 1 M.2 SSD, and 1 SATA HDD.
Consider resetting the CMOS. There’s a jumper you can use for this. If not, remove the CMOS battery, disconnect the PSU, attempt to power it on—this should discharge any stored current, then reinstall the battery. I think the BIOS is likely set to revert to its previous state; ensure it’s switched off.
It looks like the PSU might be worn out from frequent on/off cycles—PSUs aren’t built for that kind of use. The CMOS battery could also be affected because you often power off the system, which puts extra strain on it. I suggest replacing it with a Corsair RXM 650 if possible.
I took out the CMOS battery and reinstalled it, which stopped the strange symptoms. I reached the login screen before the system restarted twice—once with display off and once with it back on. My 3060ti stopped lighting up (normally white RGB then software-set colors), but RAM RGB remained active. I swapped it with a spare RX570, same issue: no display, but GPU lights now. Possible causes: PSU cable, PSU unit itself, or motherboard GPU slot. Some observations: - Reconnecting keyboard on both front and back panels triggers LED activation - Cleaning the GPU slot caused GPU to light briefly before power loss - After cleaning, I heard a power cut and it restarted - RAM RGB faded and then returned to normal (fans spinning) - Keyboard LEDs appeared briefly when num lock was pressed, but didn’t respond - Pressing numlock didn’t illuminate the LED.
The power-up resolved the problem, but I had to reset the CPU clocks and XMP settings. When I tried it again, the GPU light flickered without booting, then stopped working after a few restarts. After that, 3DMark ran well and handled load. I remember having XMP issues at first, which might have caused this. The long break of a month and a half seems to be the trigger now. I’m planning to buy spare CMOS batteries just in case. Also, it looked like the system clock was off when I booted into Windows.