Voltage conversion of Accuphase E-4000

I hear it is basically solder wire to a different tap on the same transformer. Now, trick is to know WHICH tap is it... Typically transformer should have 3 input taps - 100, 120 and 220 which should cover all the world voltages. 100V should be the one currently used. The other should not have any wires connected. Most outer should be 220 (outer means most turns of the wire between it and the common wire). If you have base knowledge of linear power supplies you may be able to guess it. Or find a person who does. 

This may help - service manual. You may be able to find your exact unit, or use schematic as a reference. See page 19.

@mikhailark

Thank you very much for providing information on voltage conversion of E-4000. I will try to do the conversion on the basis of information you provided and I will let you know of result.

Thank you very much again.