change the ploarity of charger 12 v PIN VIN

hi everyone spv i have a arduino UNO powered by a 12v charger with a pin vine, i change the polarity after larduino does not televerse. please help me

spv?
Change polarity?

You likely damaged it.
See the diode there, and Vin is after it? The diode protects against reverse polarity.
So the 5V regulator, and the parts after probably saw a high reverse voltage, damaging everything.