i'm not sure how to fix it but i'm sure the problem is in the circuitry behind the control buttons on the unit. i am sitting here with the same tv you have taken apart with the control button unit unplugged. the tv is staying on but i obviously can't change channels or anything. as soon as i plug the control unit back in the tv starts turning on and off again. i'm looking for this part online now, hence how i came across your post.
Mindspin19@aol.com, December 2007