I have this Panasonic P42ST30 Plasma TV since 2013 and last week when I turned it on a black bar appeared:
(Shot using Asus Zenfone 3 phone)
Found out that around CB4 Connector of buffer board had a burned 1-ohm Resistor and a damaged chip Capacitor.
ordered replacement buffer board at ebay for $35.00 including shipping. Have to wait for it's arrival on or before Dec 16.