I accidentally fried something on my nodemcu board, but had no idea what (magic smoke, etc.). The usb serial bridge (CH340) still worked, and programming from the Arduino IDE seemed to be ok, so I tried saving the board. A bit of poking around with a multimeter found that the 3.3v line was very low at roughly 1.5v. First had to locate the offending regulator, then cut it out from the board (soldering would have taken too long, and I just got a new pair of wire cutters). Soldered an LM1117T-3.3 regulator I had directly to the external pins (verified before that the 3.3v line was the same at the regulator and pin), and the board is alive and well.

First picture shows original board, burnt 3.3v regulator right above the yellow capacitor.
Second picture shows old regulator cut out and new regulator soldered in.
Third picture shows another angle of the new soldered regulator.