25 tubes! Barker Brothers must have been trying to take the market for inflated tube count radios away from EH Scott!
As an aside, I think that your second tube type listed should be a 6AG5 and the two rectifiers should be the same type, most likely the 5Y3 variety.
Beyond that, you can still get pretty far without a schematic, although an alignment procedure would be extremely helpful for this monster. I'd start with the power supply and then work backwards from the audio output section to the front end. Generally totally dead sets are caused by a bad tube, missing or low B+, an open interstage coupling capacitor, or a bad tuning coil. Less likely is a burned out audio output transformer. A set with this many tubes HAS to be an AM/FM set- so, is it dead on one band, or both? Can you hear a low hiss coming out of the speaker, or is it totally silent?
If dead on both bands, look for common causes- faults in the power supply or audio amp stages.