Need a schematic for old Mallory power supply

I am looking for a schematic for a Mallory Rectopower model 12 RS 6D. It is unusual in that it has 4 copper oxide rectifiers that do not seem to be connected in a bridge configuration. The method of selecting 6 or 12 V is also "different". The variac type of transformer also puzzles me.
Bruce in the Peg

I have a similar type of thing. Haven't opened it it up in years. I did change a cap. If I r emember, it's esentialyy line regulated (the variac) and the cap for regulation. I think there was a thermal breaker inside too. The only real choices are full and half brdge, but a half with protection diodes would work too. Remember this was used as a battery charge too. So, a half bidge and two potection diodes makes a lot of sense.