First, try a reset. Unplug the power cord for a few hours and try again.
Second, try the jiggle and wiggle test; just shake the set around or bang it with your fist to see if the cause is from a loose connection. Wiggling and jiggling the set can often wake up a bad internal connection or cold solder joint.
If you need a tech service here you are a tech website www.tvrepairjacksonvillefl.com
daniel
October 2012