Had a weird power supply hum that turned into a full motherboard swap

I was at a small office in Springfield last week fixing a desktop that wouldn't boot. The owner said it just died with a pop. I swapped in a new power supply, but when I turned it on, there was this low hum from the board near the CPU. I checked all the caps with a multimeter, and one near the 12V rail was reading way off. The board was old, so instead of trying to replace the cap, I just told them a full board swap was the best move. We got a basic B550 board and a Ryzen 5, moved everything over, and it fired right up. The whole fix, with parts and two hours of work, came to about $350. They were just happy to have their files back. Ever had a bad cap make a noise like that before a total failure?

2 comments

2 Comments

dakotam171mo ago

Yeah, that low hum is a classic death rattle. Seen it a few times where a bulging cap starts singing before it fully pops. Good call on the full swap with a board that old.

the_river1mo ago

Oh man, that hum is the worst sound! I had a cheapo office PC do the exact same thing last year, a quiet buzz that got louder for a few days before it just quit for good. You're totally right to swap the whole board on an older system, chasing bad caps is never worth the time. That price you charged is more than fair for getting them back up and running without any headaches.