spanish Zenith System 3

[tritwi]

Thank you very much Zeno for the useful informations. Do you know if a service manual exist for the system 3 chassis? the original one i mean. I think i should find some sort of schematics before attempting to troubleshoot both my tvs. If i get to know the number of the service manual then i could try to find one on ebay. My original 13" system 3 has a problem with the speaker and G2 setting. it keeps changing the picture background showing retrace lines but it is impossible to obtain a dark picture.