I have a strange problem with my tv in the downstairs living room. When the tv is on no matter if it's sd or hd I have strange black marts on the tv. I don't see them when the tv is off (even used a flashlight to see if I could see them with it off). I don't see them on tv2. I don't have anything else hooked up to the tv to test it without Dish running on the tv. How can I find out if this is something wrong with the receiver or the tv?