Too much "Interlaced" on old Sony

[tesna]

I had this 10+ year old Sony 29" Trinitron, not the flat/wega series (I will look the exact model tonight). The TV produces too much interlaced lines even at long distance. Other than that is fine though, the colors still OK, geometry OK etc. For example, if the TV produces solid color (for example RED), I can see that color has very visible white interlacing lines. I hope my explanation makes sense to you . I tried to adjusting sharpness, basic brightness/contract calibration, but no luck

I also had other Sony CRT (newer model though, flat, DRC etc). I can't see flicker/interlacing lines when viewing on normal distance. I only saw them when I take a closer look on the screen.

So, I'm wondering is this normal on old CRT? if is not normal, is it hard to fix it?

[NST]

Do the lines slope at a slight angle? If so, this symptom is known as flyback lines, and normally it means the tube has seen better days.
There are also a few other problems that can cause this. I'd suggest you have the TV checked by a repair company, they'll let you know if it's repairable or not.
If it is the tube, then it won't be economical to have the set repaired, as new tubes (if still available), can cost upwards of £300

[tesna]

Thank you NST for the response I really appreciate it. Oh well, maybe its time to get a plasma/lcd