There is no "AC" cord. The AC adaptor is a full wave bridge, unfiltered
putting out 15 V.
Holding cord with the key to the right we will number the pins
1 2 3
key
4 5 6
Use pins 2 & 5 pin 5 is POSITIVE
This assumes the US model is the same as the EU model.
73 Zeno
LFOD !