Mercury 1501 sig generator help
 

Bought one of these in Dayton.. "...oh yes, I'm pretty sure it works....",
and it doesn't.

Not much to go wrong with this, there's B+ and filament voltage present.
Any suggestions? Anyone have a schematic? I see from opening it up that
it is early Japanese, was this a decent sig generator in its day?

Thanks,
John KB5AG