Zeppelin Connectivity Malfunction on SPDIF

Good day to all members,

Two days now my input and specific my SPDIF input does not operate. I have checked also the optical wire for malfunction and replaced it with a new one but the issue remains the same. The only input that operates is the iPod dock. I am trying from the remote control to change the input device (for example green indicator is for the AUX in Optical and blue indicator is for the ipod dock connectivity) A question to the technician, mentioned that the input connectivity is separated in 2 plaquetes the front with the IPOD connectivity and the back with SPDIF, RF input Etc. Is there any wiring diagram or any suggestions?

Many thanks for your reply.