[Ron Ramirez]

Yup, that's a 70 chassis.

Don't know how it could have operated properly with a transformer from a Model 20, unless someone used one half of the center-tapped 5 volt 71A filament winding on the 47, or if they used the center tap for one side, and both ends of the other side...

At any rate, you will need a power transformer, one designed for your 70.

Oh, when I acquired my 650B, its power transformer was torn from the base...only because some dimwit removed the mounting bolts.