As promised, attached are photos of my Dongan transformer and its original box. It is the Champion model and is rated at 100 watts. Not sure when this was made but that sentence in small red print on the label on the box where it is partially torn ends with the words “… for 18 years”. “David from Dearborn” said they were founded in 1909 so that would mean this transformer could have been made as early as 1927.
Bill
