Recently the video has begun to drop out. Audio is ok. Just as the Video goes out there is a "Buzz" sound that eminates directly behind the Selection buttons on the fron right top side of the TV. Turing the TV off for a few seconds then back on usually brings the video back. and it may be ok for just a few minutes, or a few days....it varies widely and is close to failing altogether. DC input voltage is about 13.4 - 13.9 volts. Is there a component that I can change to eleviate this problem?