My PC suddenly shut down while sitting idle, and since then it usually powers on for about half a second before the PSU clicks and everything turns off. I recently upgraded the CPU, GPU, and RAM, and I have already replaced the older motherboard and PSU while troubleshooting.
The system sometimes stays powered on if the CPU 8-pin cable is disconnected, but it still does not produce a display signal. With the replacement motherboard and PSU, it may repeatedly power on and off several times before remaining on, although the monitor still stays black.
I have tested different RAM configurations, old and new RAM, both GPUs, different modular power cables and wall outlets, BIOS resets, reseated components, checked the CPU pins, removed the GPU and RAM in various combinations, and disconnected the case buttons, LEDs, front-panel connectors, and USB devices. I have also reapplied thermal paste and tried running the system with only the CPU, cooler, motherboard, PSU, and one RAM stick.
The current parts are a Ryzen 7 5700X3D, Thermalright Peerless Assassin cooler, Gigabyte Radeon RX 9060 XT 16GB, KLEVV BOLT X 32GB 3200 MHz memory, Gigabyte B550 Gaming X V2 motherboard, and Gigabyte Aorus Elite P1 850W PSU. Could this be an outdated motherboard BIOS, a short in the case or USB ports, a faulty CPU, or a power-delivery problem?
2 Answers
Since changing the PSU did not solve the problem, check whether the power-good signal or another power-protection circuit is being triggered. Repeated clicking and cycling is not something to ignore, and it is not usually explained by a missing BIOS update alone. Testing outside the case with no USB devices or front-panel connections will help distinguish a shorted port, misplaced motherboard standoff, or case wiring problem from a failed component.
The symptoms may be caused by more than one issue. An immediate click and shutdown can mean the PSU is detecting a short or another serious fault, especially since disconnecting the CPU power cable changed the behavior. However, the replacement B550 board may also have an older BIOS that does not support the Ryzen 7 5700X3D, which can result in fans spinning without any display.
Test the system outside the case on top of the motherboard box with only the motherboard, CPU, cooler, one RAM stick, GPU, and PSU connected. Leave all case wiring, front USB ports, and external USB devices disconnected, and start it by briefly bridging the power pins with a screwdriver. Also use the board’s Q-Flash Plus feature to update the BIOS from a USB drive. If it still repeatedly cycles or fails to post after a BIOS update and an out-of-case test, the CPU or motherboard may be defective.
I may be dealing with multiple problems at once, so I’ll try the BIOS update and the barebones test. Is repeatedly powering on and off normal for a BIOS compatibility issue, or does that point more strongly to a short or hardware fault?