🎵 Who let the smoke out? 🎵

Man it reminds of the time when a coworker discovered he and I designed a board with a couple mosfets (I think, it was a pretty big sucker too) backward.

You know, $400 board, $600 components + 8 hours of having the things soldered on by techs. Not a cheap thing, but relatively inexpensive compared to the cost to design it. We didn’t know it was backwards at the time. We actually didn’t know it didn’t serve a purpose at all for what the circuit was meant for. He’s flipping switches and we can’t get one of the signals across to the interfaced device.

We’re getting pretty frustrated with it, so I go back to my desk doing the math by hand. No matter what, given the part and the circuit drawing, it should work when an expected voltage got applied to trigger the FET. I get a call from the lab: “I fixed it.”

The dude got out a bench power supply, and took the board out of the box and started trying to force it to switch. He ended up applying higher and higher voltages in scenarios I didn’t understand (he’s the EE I’m a comp e) and let’s the transistor smoke out. Course this shorts the signal we were trying to get through, which we discovered was what we wanted in the first place.

So when he runs into the problem with 2 or 3 more of the same FETs he just blows through them again to save time. We did update the board design and updated the BOM to just short those pins instead of blowing up a transistor.

But. Yeah. Always pay attention to the parts you order vs the parts you expect from your drawing. Because even using the board correctly with the wrong parts results in magic smoke madness.

Gotta keep a spare bottle or 2 around just in case.

Is this an AVE reference?