[Arran]

Grunows of that era suffer from the same bad coils that Philcos do.  I have a model 1162 that is in pieces and have worked on a couple of model 750s.  Both models use the same coil and band switch sub assembly and they all had coils that needed to be re-wound.  The 750 is one of my favorite sets and the 1162 should be even better.

 Well not the same coils as Philcos, but they do seem to suffer from open coils much like Philcos do. Whether they fail for the same reason I do not know, the Philco coils seem to fail because of the type of plastic they chose to use as an insulator between the primary and secondary windings. Depending on whom you talk to it's either because this plastic expands and snaps the wire mechanically, or because it leaches something corrosive that eats through the wire.
Regards
Arran