Magnvox 32md357n lcd tv built in dvd. we are sinors and we have Comcast as iour cable co. what is happing is when we turn on cable box and get a station. the on & off buttion has a red light. When pusshed it turns green (so does the built in dvd player) thn it goes off in a couple of seconds. We know the tv orks but cant stay on. Help we are on ssn and can't afford to purchase a new tv. is there something we can do to fix i? Tjhank You God Bless.