Thank you orsetto for your answer. Sorry if my description is confusing, I tried to keep it short and covering the most.
Yes, I can understand that my camera has two light meters and the viewfinder is only for guidance. I usually only use auto mode, so the only problem I will encounter is in low light situations I guess. I'm just very sad that it suddenly happened, as I'm very happy for the camera.
When you mention CdS is subject to aging, are you referring to that this could also be a reason for my problem, or just that it also is a common problem with the light meter in the viewfinder for OM2N?