Changed my mind about those cheap power supply testers after a weird board meltdown

I mean, I used to think those little $20 power supply testers were fine for a quick check, you know? They light up, you get your voltages, good to go. But last week, I was fixing a gaming PC for a friend, and the tester said the 12V rail was fine. I plugged the board in, and it powered on for maybe three seconds before I saw smoke near the CPU socket. The tester missed a huge ripple on the 12V line that my old oscilloscope picked up right away. It was just dumping dirty power straight into the board. Now I'm back to hooking up the scope for anything that seems even a little off, even if it takes an extra minute. Has anyone else had a tester give them a false clean bill of health like that?

2 comments

2 Comments

the_lucas1mo ago

Honestly, that's a scary story. I had something kinda similar happen with a cheap car battery tester once. It said the battery was fine, but the car kept having weird electrical gremlins. Took it to a shop with a real load tester, and it showed a bad cell the cheap one completely missed. Makes you wonder what else those little gadgets are glossing over.

amy_sanchez1mo ago

My old multimeter from a discount bin lied to me for three years. I trusted its voltage readings until my entire project board smoked itself. Turns out it was off by like two whole volts. Now I just assume anything under fifty bucks is probably guessing.