Investigating broken ESP drone

[rafalk7]

Hello,

Ive got one of ESP drone 1.2 for excercises.

One of.my students accidentally soldered + and - pins on a ESP drone 1.2 and proceed to test it.

We'ver seen small smoke from it.

After inspection and desoldering pins, nowy once connected with a battery, that motor is turning constantly without any input from a controller.

I suspect some broken diode.

Can you help with investigating this problem? How to Fix it?