If you are using cable and the signal is connected to the TV through the regular cable wire, then the TV must be in TV mode to work properly. If you are using a cable box with that TV then the TV must be on channel 3. If the screen shows AV 1, then the TV is in the AV mode (red, white and yellow RCA jacks), and you most likely accidently hit the INPUT button on the remote. Pressing 0 3 or INPUT a couple of times on the remote should bring your picture back.
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