Polaroid TLA-1511c screen goes black?

My TLA-1511c has the logo screen, channel indicator and picture come on and after 10 seconds the screen goes black. When turned of and then back on immediately, the screen goes black in about 1 second or not at all. After it sets over night, the pic will stay on for 10 seconds again. I can't see the picture by shining a flashlight on the screen, but the menu screen is faintly visible. I have replaced three capacitors on the PSU board (on the backlight side of the board) and two 1000uf and three 470uf caps on the main board with no change in the problem.