My uncle, a mainframe guy from the 80s, told me to always check the power supply first.

I spent two hours chasing a weird boot loop on a desktop last week before I finally swapped the PSU. It was a Corsair RM750x that was just barely failing. Anyone have a favorite diagnostic tool for testing them without a spare unit handy?

3 comments

3 Comments

xena_anderson2mo ago

That "just barely failing" part is the worst. I had a similar thing with a fan controller that only acted up when the room got warm, which made me doubt the power supply for way too long. Sometimes the problem hides in plain sight.

lisa_murray5d ago

@tylerw92 brings up a good point with the multimeter but that only catches the big stuff, you know? I had a similar problem once with a system that would just randomly restart when I was about 15 minutes into a game. Turned out it was the wall outlet. The voltage was fine at idle but would dip just enough under load to trip the PSU's protection. I swapped everything out before I thought to check the actual power coming from the wall. Grounding issues can be sneaky too, like that fan controller problem. Sometimes the problem is in the house wiring, not the computer parts.

tylerw922mo ago

A Corsair RMx series failing like that is genuinely surprising, they have such a solid reputation. Your uncle's advice is painfully true, but it's so easy to skip right past it when you're sure it's a software or memory issue. Those barely-there power problems are the absolute worst to track down, they mimic everything else. I just use a cheap multimeter on the standby rail now if I don't have a spare unit, but it's not a perfect test.