My PC worked normally for almost a year, but while I was browsing the web it suddenly powered off and restarted. About an hour later it shut down again, except this time it would not boot back up. Pressing the power button makes the PSU click, the fans barely begin to move, and the system immediately powers off. Holding the button caused repeated rapid clicking. After switching the PSU off and back on, it may click once again, but now the fans do not spin at all.
I have reseated every PSU cable on both ends, checked for obvious shorts or burning smells, removed the GPU and other components, tried booting with only the CPU, motherboard, PSU, and one RAM stick, tested the other RAM stick, and reset the CMOS. I had previously enabled some EXPO memory settings and applied a small CPU undervolt.
The system uses a Ryzen 7 7800X3D, Noctua NH-L12S cooler, ASRock B650I Lightning motherboard, Corsair SF750 PSU, 32GB of G.Skill Flare X5 memory, a Zotac RTX 5070 Ti, a Fractal Terra case, and a Samsung SSD. What is the best way to determine whether the PSU, motherboard, CPU, or another component has failed before I start sending parts in for warranty service?
3 Answers
The previous EXPO and undervolting settings are worth considering, but clearing CMOS should remove those settings. Ryzen 7000 systems did have known issues involving excessive memory-controller or SoC voltage on some firmware versions, so once the machine is working, update the BIOS and leave EXPO and undervolting disabled until stability is confirmed. A failed CPU is possible, but the PSU and motherboard are usually easier to isolate first by swapping in known-good parts.
The quickest next step is to test with a known-good PSU, even though the SF750 is generally a strong unit. A failing PSU or a protection circuit reacting to a short can produce the click-start-shutdown behavior. Since you already tried removing the GPU, test with only the motherboard, CPU, one memory module, and PSU, using the borrowed unit and the correct cables that came with that PSU. Do not mix modular cables between power supplies. If the behavior is identical, the motherboard or CPU becomes much more likely.
Repeated clicking usually means the PSU is attempting to start and then shutting itself down because it detects an overcurrent, short, or another fault. Inspect the small-form-factor case carefully for a misplaced motherboard standoff, trapped cable, loose screw, or a connector pressing against the chassis. If possible, remove the board from the case and test it on a nonconductive surface with only the CPU, cooler, one RAM stick, and PSU connected. That can rule out a case-related short. If it still cycles with a known-good PSU outside the case, warranty testing of the motherboard and CPU would be reasonable.
I already tested without the graphics card and the system still immediately shuts down. I’ll try a known-good PSU next before assuming the CPU or motherboard is dead.