Converting NAIM NAIT 3 from 230V to 120V

[cboran]

A friend of mine from the UK whom is living permanently in the USA has finally dug out his Naim Nait 3 from 10 years (!) of storage, and is "finally getting round to building up a proper Hi Fi system". His Naim amp is still internally wired for 230 V operation and he would like me to convert it to 120 V operation.

I'm an electrical engineer and am prepared to do the work for him, but I would like to see a schematic or gain a better understanding of the mains transformer wiring before I make any modifications.

Any help (schematic or description of procedure) would be greatly appreciated.