Sony KP-51WS500 CRT TV

Hi all, In my basement I have an old (but goodie) big CRT TV: Sony KP-51WS500. This TV is connected to a laptop through a DVI cable (with the 1080i resolution). I have the following problem: Basically, curved blue lines (and also red lines) are displayed. I tried to perform the Flash focus function but no luck. Also I noticed that some shadows/images are displayed in background (it's like some images that interfere), but I don't have any cables/antenna connected to the TV. In your opinion, where could the problem be? Can I try to fix something with the Service Menu? I never tried to fix a CRT TV, but I don't have problem soldering, using a oscilloscope, multimeter, replacing IC, caps etc :-) Thank you in advance for your help. Regards.  

Connect With Techlore