Switch on immediately using a confirmed PSU and swap the motherboard.
Switch on immediately using a confirmed PSU and swap the motherboard.
Hi everyone, a year ago I set up this system and experienced no problems until two days ago. When I powered on my computer, it completed the BIOS setup and started booting Windows, but then it shut down abruptly. I attempted to restart it, and for a brief moment the fans spun before stopping. This was the only odd occurrence—no smoke, no sounds, no error messages or codes. The motherboard debug lights flashed once, seemingly during the boot process, though it's hard to confirm due to the short duration. Additionally, after detaching my graphics card and testing without it, there was no difference either.
My initial assumption was that either the power supply unit or the motherboard had failed, so I purchased a multimeter and tested the PSU. It functioned correctly across all pins, even when disconnected from anything else. Consequently, I ordered a new motherboard—MSI MAG 870e Tomahawk Wifi, as it was the closest match to my current one and available that same day. After installation, the system behaved identically. This new board displays hexadecimal error codes instead of just four lights, but it powers off before changing from the initial 00 code upon startup. I observed the PSU indicator cycling through red, green, then red again before shutting down when connected to the motherboard, leading me to suspect a faulty PSU under load. However, after replacing it with another identical unit, the behavior remained unchanged. I rechecked all the pins, even testing the CPU power cables just to rule out any damage.
I’m unsure what to inspect next, as if the issue was related to the CPU, the motherboard indicator on my old system or the debug information on the new board would have provided clarity.
In short:
- Computer shuts down immediately after powering on
- Replacing motherboard had no impact
- Disconnecting graphics card also didn’t affect performance
Not necessarily. You've modified the mobo, changed the PSU, removed the GPU and possibly linked the monitor to the iGPU output on the mobo. Swapped the power-on switch for the reset switch. All attempts have failed. In my opinion, the CPU remains untouched. In these cases, I opt for the cheapest compatible CPU and test it. It's also possible the fan for the cooler is connected to the wrong mobo header; most BIOS will shut down the system if it can't detect a CPU fan on the correct port. With an AIO, verify the pump and ensure the radiator fans are connected to the right headers. This setup simplifies troubleshooting for a big air cooler. You might want to inspect the 7950X3D for bent pins using a magnifying glass before purchasing a test CPU. Have you tried other RAM options?
It seems the issue was with the CPU. I plan to file a return or exchange since the warranty covers three years and I've only used it for roughly 14 months. Appreciate the advice and ideas everyone provided.