Mark Levinson 390S 110v/220v again


There was a thread about this topic two years ago, but remains unanswered regarding the 390S specifically.

Does anyone know how the 110v/220v conversion from a Mark Levinson 390S work? In other words, is it as easy as changing a jumper setting?

If you explore more treads you see that newer Levinson gear is not easily convertable. Step-down converter does not help either, because newer Levinson stuff has a chip inside that detects if voltage is 60Hz or 50Hz.