I don't know if I'm making a big thing out of nothing or not I was able to get a copy of a repair manual which covered several models of machines. Do your manuals have much information that is machine specific? Or is it a primer in how to weld? Thanks in advance.
Forney is still in business and can provide you a manual. Their website lists this manual for the C-series AC welders, but you may be able to get one for a C-3 from their customer support folks: