Had a weird power supply issue at a client's office in Tacoma yesterday

I was replacing a hard drive for a small accounting firm, and the new one wouldn't boot. Spent an hour checking cables and BIOS before I noticed the power supply was making this faint buzzing sound. Turns out the 12V rail was dipping under load, just enough to cause instability. I mean, I always check voltages now before I assume a part is dead. Has anyone else run into a PSU that fails quietly like that?

3 comments

3 Comments

jenny_jackson1mo ago

Ugh, those silent killers are the worst.

xena8861mo ago

Yeah, that "fails quietly" thing is exactly right. I had a similar one last month where a computer would just randomly freeze. It passed a quick power-on test, but under any real load the 5V rail would tank. No weird noises, no burning smell, just a perfectly still and dead machine. Took me forever to figure it out because I swapped everything else first. Now my power supply tester lives on my bench.

walker.michael11d ago

Honestly, that "fails quietly" part is so true. I read a forum post where a guy had a PSU that only messed up the 12V rail when his graphics card spun up for a game. His system would just black out, no warning at all. Tbh it makes you trust those basic power-on testers a lot less.