I bought a Pioneer Elite Pro-510HDTV along with a separate SH-D09 Digital Tuner in 2001. Until recently the system has been trouble free. However, lately, the 510HD presents an intermittent severely deteriorated picture. The problem presents itself in the following way. There is a sound of a pop and at the same time, the screen darkens to the extent that screen images become almost unrecognizable. After a few minutes of this dark picture there is the sound of another pop and the screen regains its normal picture. What's going on? What do I need to correct the problem?