I have Magnavox 24 inch DVD Triple combo model MWC24T5 that is making a knocking noice coming from the TV/VCR slot and then the TV turns itself off. We tried unplugging the TV to try to get it to reset and it worked good for a while but it is making that noice again. The VCR tape will play and the noice will start when the tape is playing. Also, we have tried resetting the time on the TV that didn't work. The TV was working fine and the this all started happening. Do you have any suggestions what to try to fix these problems? The TV is about 3 years old.