a year ago i had cable installed in my home. when the cable box was turne’d on a loud “snap crackle and pop” occurred and the box fried. every since my 50″rca DLP has a distinctive hum when it is on HD. currently i have both HD and coax hooked up. while on coax no humming occurs. when switched over to HD the humming begins. whats the point of having HD if i cant stand to watch it. can someone please help me with this