hifi engine

Electro Voice XAM Mark III

Does anyone know where I can find the schematics for the Electro Voice XAM Mark III ??? Its a receiver made by Electo Voice to a 60's store called E.J. Korvette. Got it at Goodwill and wanna repair/modify it, but just can't find the schematics. I could only find the one for a similar version that has a tuner with it too, but I guess it's a tube one, and the one I got is solid state.