If you are a CVRS member you can request schematics from schematic services.
radiomuseum seems to have service data on it here:
https://www.radiomuseum.org/r/rogerstube … mbina.html
if you don’t have access you might have to write them a note to get signed onto that forum.
also there is a good post on ARF that might prove helpful, evidently it may be listed under grigsby grunow?
https://188.8.131.52/~antiquer/forums/v … &view=next
I picked one of those up some years ago , but it was just the cabinet. I think I have some bits of the cabinet around like the pull handles, perhaps some parts of the top. It is quite nice for a radio phono combo radio.