Schematics or service manual Proton AA-461 PRO, power amp

[retro2]

Hi.
Does anyone have an ide of where to find shematics or service manual for my power amp? It's an 1994 Proton Dual mono AA-461 PRO amp.

The right chanel is gone, both transformers and both psus is working and all output transistors are OK but the signal gets lost somewhere along the way.

Thanks in advance if anyone can help me with this. Regards Hakan in Sweden