panasonic tx50a400b

[t1412]

hi fells'a anyone had this fault, panasonic tx-50a400b input selection keeps popping up on the screen, the customer is dropping it off in  an hour, right took back off nothing on the psu i can see, menu pops input menu pop up  power standby light flashing it's got mind of it's own thanks ps happens when the tv gets warm 

shaun