CRT monitor display problem

CRT monitor (10years old, Samsung) of my pc does not display any picture but only some color lines like the image I've attached.
The problem started few days ago for the first time in its life.
At the beginning the problem used to stay for few seconds and come back to normal display on its own or with a knock of my hand.
Gradually the problem increases and now it rarely become normal.
I opened the case, cleaned inside with air & brush. Then re-soldered all the component joints of the small circuit attached with the picture tube.
But nothing happened, the display is still like that.
What is the problem? What should I do now?
please suggest

I would suggest it's possibly a frame fault, the fault is possibly actually 'no picture' with the collapsed scan off the screen, and the rainbow effect you can see is reflection of the electron beam off the top/bottom of the glass inside.

It's hard to tell just from a picture, but that's what it looks like.