I too have a B66-XL with the Cromega B head that is missing the power supply. Luckily it came with the condenser head too, but one of the condensers is missing. Even more luckily I have a B22 with the condenser head that has one scratched condenser. Between the two enlargers and three heads I managed to put together one working condenser enlarger. For the price of a couple of lens boards.
What I can not understand is what in the heck happened to all those missing parts?