Dust bunny autopsy: how I finally found the real cause of those random restarts

I had a machine at a shop in Austin that kept dropping out during stress tests, no BSOD, just a hard reset every 15 minutes. I checked temps, swapped RAM, even reflashed the BIOS, zero luck. On a whim I pulled the PSU and opened it up, the intake fan was caked with a solid layer of lint that looked like felt. After I blew it out with canned air and cleaned the fins, I ran the same test for an hour with no drops. My question is, how often do you guys actually open up the PSU for cleaning, or do you just replace them?

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sullivan.john17d ago

Damn, that felt-like lint description hit home for me! I've seen exactly that before, and it's wild how it turns into basically a solid barrier over time. So here's my question for you, after you cleaned it out, did you check the PSU's fan bearing or the actual motor for wear? Because in my experience, that kind of dust buildup usually means the fan was struggling for a long while, and sometimes the bearing gets rough even after you blow it clean. Mine will spin fine for a day, then start making that grinding hum like it's about to give up. I'm guessing you got lucky with just the lint, but I've had to replace two PSUs where the fan was the real casualty, not the airflow. Just curious if you noticed any weird noise before you cleaned it or if it was totally silent the whole time, since that usually tells you if the fan's got life left in it or not.