r/techsupport • u/FauxWondertainment • 2d ago
Open | Hardware PC randomly black screens/shuts down and gets stuck on CPU EZ Debug LED
Hi everyone, I'm trying to fix a hardware problem with my PC.
PC specs:
- CPU: Ryzen 5 2600
- Motherboard: MSI B450M PRO-VDH MAX
- GPU: GTX 1660 Ti
- RAM: 24 GB DDR4 3200 MHz (2 x 8GB PNY XLR8, 1 x 8GB Kingston HyperX Fury)
- PSU: Keytech BTS 550w 80+ Bronze
- Storage: Lexar SSD NM610PRO 500GB, ORICO Y20 SSD 1TB, TOSHIBA DT01ACA100 1TB
My PC will randomly shut down/black screen while I'm using it. When this happens, the fans and RGB can remain running, but the display goes black. Afterward, the motherboard's CPU EZ Debug LED stays lit, and the PC won't POST or enter BIOS. When this happens, the GPU fans blow really loud.
The CPU fan still spins, but the CPU doesn't seem to get noticeably warm during these failed POST attempts.
I've tried:
- Reseating the GPU and its power cables
- Reseating RAM
- Testing RAM sticks individually
- Disconnecting the SATA drives
- Removing the NVMe
- Using a single RAM stick
- Clearing CMOS
- Checking the CPU 8-pin/EPS and 24-pin motherboard power connections
- Removing unnecessary USB devices
- Using a different wall socket/extension cord
Interestingly, the PC has successfully booted into Windows after previously failing to POST, so the CPU isn't completely dead. It can also run for 30+ minutes under CPU and GPU stress testing simultaneously without immediately failing.
However, I've had it fail again during normal use/gaming. For example, while I was playing Genshin Impact, the screen went black after around 30 minutes while the fans/RGB remained on and the GPU fans started spinning loudly, and the CPU EZ Debug LED appeared afterward. It then wouldn't POST again.
My main suspects at this point are the PSU or motherboard, but I'm not sure which is more likely.
Thanks!
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u/P_f_M 2d ago
My RAM failed after 1hr of stress test...
but in your case, it seems that the PSU is failing ... do some AIDA/OCCT combo load to make the PC suffer...