I have a prebuilt gaming PC with a Ryzen 7 9800X3D, an RTX 5070 Ti, and an X670 motherboard. It was shut down but still plugged in, and I noticed the keyboard LEDs were on while I was away cleaning for several hours. When I returned, the computer would not power on at all. My girlfriend's PC was connected to the same power strip and still works normally. I also tried swapping power cables, but that made no difference.
The keyboard lighting initially made me think the PC was receiving power, but now there are no motherboard or USB lights either. The system is still under a year old, though the warranty expired about two months ago. A repair shop quoted $69 for diagnosis and around $179 for parts and labor if the power supply needs replacing. I'm trying to save money and may wait until next month.
Could a power surge affect only one computer on the same strip, or was the PSU probably failing on its own? Is there any connection between the 9800X3D, RTX 5070 Ti, and X670 platform? What should I check, and how can I prevent this from happening again?
3 Answers
The keyboard light doesn’t necessarily mean the PSU was healthy. USB standby power comes from the PSU’s 5VSB rail, which can remain active even when the main power circuitry has failed. If there are no lights or signs of life now, a failed PSU is a reasonable first suspect. Since the other PC on the same strip is fine, a general surge is less likely, though it can’t be completely ruled out. Have the PSU tested or replaced with a quality unit before assuming the CPU or graphics card is damaged.
For the future, a basic power strip does not provide meaningful surge protection. Use a properly rated surge protector, or ideally a UPS if your budget allows. Turning off the switch on the back of the PSU helps, but unplugging the system from the wall provides better isolation. Also check whether the prebuilt manufacturer or individual components have any remaining warranty or replacement coverage before paying for repairs.
The warranty ended only a couple of months ago, unfortunately. My older PC has been fine for years, which is why this failure on the newer and more expensive system caught me off guard.
There’s no known problem with pairing a 9800X3D and a 5070 Ti that would normally cause this. The most likely explanations are a defective or low-quality PSU, a protection circuit that latched after a transient, or another failed component. Try a complete power reset first: switch the PSU off, unplug it, hold the case power button for about 15 seconds, wait a few minutes, then reconnect it and try again. If it remains completely dead, professional diagnosis is safer than randomly replacing the CPU or motherboard.
That makes sense. I didn’t realize the keyboard could stay lit even if the PSU was already failing. I’m not very comfortable opening a heavy prebuilt, so I may have a shop test it.