[Chuck Schwark]

The differences are in the Service Bulletin supplements. Sometimes there are just component changes. Sometimes a wiring change to accommodate a tube type change, usually the rectifier or audio output tube, or a combo, etc.

I provide these Code variations, when applicable, as part of the photocopy service packets explained on my site. Most current on-line sources for Philco schematic info do not include all this info Philco published.

I cannot remember what the details are for your model at the moment (at work).