Hello and sorry you're having problems.
When did the issue occur- were you connecting/disconnecting something to the set when this happened?
The reason being, is that this either indicates a disconnected or loose cable, or is a hardware failure in the Media receiver box (the AV Input box).
In order to try and correct it, and as a TEST to see if the issue is in fact- hardware related, you must perform the following steps. If you cannot then the only other option is to call a tech.
1) Disconnect the Plasma display (PDP) and the Media Receiver (MR) from power.
2) You will need to carefully remove both ends on both sides of the system cables. There are two- one is wider and has more pins than the other.
3) Inspect the ends of both cables and make sure there are no bent pins. If there are, use needle-nose pliers or a small flat-head screwdriver to straighten them out.
4) Carefully reconnect both ends of the cables making sure they are secure. If you're unable to see the connectors clearly- use a hand held mirror and a flashlight to identify where they go.
5) Plug the PDP and the MR back into power, cross your fingers and attempt to turn the system on.
Let me know what happens please.
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