Technics SA- GX130

I have Technics SA- GX 130, having issues with missing channel right does not work. I am looking for a schematic for it, my dad is 84, he wants to work on it. he still works on amps, linears, and Tv, old time TV shops since the 60's, just need a schematic, we have files cabinets full of Sam's photofacts just do not have the Sams number for this chasis.