[Arran]

A point of correction, the conversion of 25 cycle to 60 cycle power grids took place in the late 1950s, around 1957-58, aside from some industrial transmission lines, not early 1950s. Most service manual will have a parts list for the 25 cycle versions which will list the extra or amended parts values, Philco liked to add the suffix "A" to the model numbers of 25 cycle sets, like 90A or 20A, I'm not sure if they were still doing this by 1937 or not.
Regards
Arran