How to change the voltage on a FLSUN QQ
I don't know if this is the case with all FLSUN QQ printers, but mine was indeed set to 220v as the instructions/user manual indicated. First I needed to remove the bottom of the printer. Then there was a switch on the side of the power supply with the following label:



I know the picture is terrible, but the lighting inside the base of the printer was less than optimal. It should be pretty easy to find once you know what you're looking for.