My sanyo plv-55wm1 projection monitor keeps turning itself off

the problem with my sanyo model plv-55wm1 55in LCD projection monitor is that when i turn it on, it will stay on for abit but after a while it switches itself off, the television actualy stays on but their is no picture or sound. now i have asked many different people and repair men that understand televisions and they are all clueless to what the problem is and are telling me it may not b fixable, i have tried a new bulb in it but still no improvement, do you have any idea how to help me?