benda on Nostr: alright Internet, help a comrade out. soldering a new power supply plug onto this ...

alright Internet, help a comrade out.
soldering a new power supply plug onto this little tire inflator compressor. the old plug is long gone. how do I identify which of these two wires is power and which is ground?
I have a dmm and most other tools if needed. well, oscilloscope is at home, but I don't think I should need that (I hope).

#electronics #electricity #diy #fixit #wires #cables #soldering