My 48" magnavox projection screen

Model no. RL8544

Chassis no. PTV385-A001.

Im having some problems, and hope you can help.

Was working fine, then picture went black, Still have perfect sound, but no pic.

Pic came on, then went out while I was watching, If I turn it off, and on again picture will come on for a split second, then go out again. picture looks fine when it comes on tho.

Im really hoping you have an answer for me. hopefully its an easy fix. I cant afford a new one.

Thanks for your help.