I pulled two interesting versions of the MC-60 schematic from there. The first is known to be incorrect, but has the major functional areas outlined. The second is the last version referenced in that thread, and (I think) has all of the errors discussed earlier in the thread corrected. But I still wouldn't trust it completely.
There's also a PDF reference sheet that describes some of the functionality of the controller.
Warning: Motor controllers like this have a floating ground. Points noted as ground on the schematic are not at earth ground potential. Using your oscilloscope to probe the internals of this circuit will likely fry the circuit, if not your oscilloscope. (I was lucky -- not with the controller pictured, but with a different one. My oscilloscope ended up fine, but the controller was toasted. Literally.) Power the controller via a true isolation transformer before probing.
