I have a 5V 65A power supply kicking around from an old audio/video editing lab that I really don't want to throw out but, I have absolutely no use for it. Is it feasible to rewind the transformers and get some new power transistors to get 12v out of it or is that really just a waste of time?
I'm not kidding about the 65A part, it weighs about 60-80lbs.
It's very easy to take apart, very old-school tech, all user-serviceable parts. It's been quite a few years since I've had it apart but I don't think the transormers have been varnished. I'll snap some pictures of it when I get home, maybe it will give you a better idea if it's worth messing with.
You may get lucky if it uses a center tapped winding and only 2 diodes for fullwave rectification. If so, you may have enough voltage headroom to convert it to a fullwave bridge rectifier and ignore the center tap.
You could also try changing the rectifier circuit to a **broken link removed**. It depends on what the loaded VRMS of the windings are for the transformer and thus how much voltage they are wasting in the pass transistors.