Suspect graphics card failure = pixel pattern on screen display

I am vainly hoping that it is not the case but I stongly suspect that the graphic card/chip is failing (on logic board).

- machine operates fine

- screen is distorted with regular patterned 'tramlines' running vertically. Desktop is virtually illegible as a result.

- same distortion occurs when plugging in an external monitor

I;m hoping that this my be a symptom of a loose connection btween the screen and graphic card. But I'm thinking not.

Greatly appreciate your input.