Mark Levinson 431 Voltage Conversion to 120V


Hi,
I've moved to US with my Mark Levinson 431 power amp, and I need to convert it from 220V (60Hz) to 120V (60Hz). Can anyone help me ? I found it has two jumpers but I am sure about the correct positions for 120V. Please let me know if you have any info on this. Thanks.
mkhwang