Here's a good one. Someone gave me their uno to fix after it puffed a little magic smoke.
After some asking, it turns out he sent "should be 3.3V" unknown polarity into the 3.3V pin in an attempt to power it that way. Which did not go as planned, and now the 3.3V pin does not output any power. Everything else functions- the uno is detected by the computer and is programmable.
Poking around, I literally sniffed out the problem component. It reads "LPFG" and what I could scrounge up, it is possibly a 3.3V regulator. However, I can find no chip code. Attached are a shots of it close up, and relative to the board. Can someone with better board knowledge help identify it completely or propose an alternative? Thanks.
Yes, I am aware of the missing 328P. I pulled it out for testing.