1990 Mk I reissue transformer wiring

[Mr. Flibble]

Hi folks! Might anyone have a 561111 transformer schematic, or various images of the guts of some domestic / import Mk I reissues from the '90s? I have the need to convert an export model from UK to US mains. It seems from multimeter readings that I probably need to swap the brown for the black wire at one end of the primary winding, and the red for the orange at the other end on top of the power switch so as to have the same B+ reduction in "tweed mode" with 120V in?