[?] Identifying burned Arduino component

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.

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Yes, I am aware of the missing 328P. I pulled it out for testing.

On the schematic the 3.3V regulator is shown as being: LP2985-33DBVR

Aw thanks. Hopefully there's nothing else wrong this thing.

Before you replace it - does the usb work?

Make sure of that before you waste the on the regulator. Abusing power can trash the 16u2 which is much harder to replace, since it's in a qfn package... you may be OK since it was the 3.3v line though.

Also check the SOIC-8 package near it (the '358), see if it gets hot. That is easy to destroy by supplying with wrong voltage / polarity too. But not that bad to replace

DrAzzy: Also check the SOIC-8 package near it (the '358), see if it gets hot. That is easy to destroy by supplying with wrong voltage / polarity too. But not that bad to replace

Yup, that gets hotter than the lp2985 chip in not even half the time.

Luckily, the parts cost a total of $8, so it is cheaper for me and him to fix than buying a new board. He said he'll pay me to fix, so whatever.

The 16u2 works fine, like I said fully programmable and detected by the arduino IDE.

$8? I see 60 cents for the regulator, 30 cents for the opamp, $3 shipping (first class shipping option) from digikey...