can i fix this or is it worth fixing?

I have a 1998 27 inch television panasonic ct-27g3w model number. Which has a beautiful picture but since last week the picture has been jumping. There is no knob on the back of the tv to fix it like the old ones used to. Since I only paid over $200.00 for it in 98 is it really worth fixing. I am amazed as the picture is beautiful it just does'nt stay still. One other thing I thought it was cable's fault since it just happened all in one day it was'nt a gradual thing. They said it was'nt them. And I kind of agree as I have a television in my bedroom and that is fine. Thanks for reading my question.