PSA: Tried a cheap multimeter vs a Fluke on a fridge call and it cost me 2 hours

Honestly I've used a $30 multimeter for years on basic stuff and thought it was fine. Last week I struggled with a Samsung fridge that kept tripping the compressor start relay. Swapped in my buddies Fluke 87 and found a 0.3 volt drop on the main board that my cheap meter totally missed. Wasted 2 hours chasing ghosts. Now I'm buying a Fluke this week. Has anyone else had a cheap meter lead them down the wrong path on a tricky board?

2 comments

2 Comments

grayb649d ago

Dude yes, same thing happened to me on a microwave board last year. My $20 meter showed 120V on a line that was actually 117V and I spent an hour replacing parts that were fine. Borrowed a friend's Fluke and found the real issue was a resistor that had drifted way out of spec. The cheap meter just couldn't catch that small difference. Made me realize how much time you waste with those things.

williams.robert8d ago

Oh, and 117V is actually totally fine for a nominal 120 line. That 3V difference is well within spec. Most utilities deliver between 114 and 126. Your cheap meter wasn't wrong about the voltage, it just couldn't load the circuit enough to show you the resistor was starving under load. A Fluke has a higher input impedance and better load testing, so it catches that kind of drift. But the 117 reading itself wasn't the problem.