Remove the back cover (10 screws)

BE AWARE: NEVER TOUCH THE HOT SECTION IF POWER CABLE IS PLUGGED IN!!!!!

Main chip is under black metal heat sink; I attached a temperature probe on the heat sink; device always shut off when reaching 50deg C in my measurements; value may vary depending on measurement devices; but effect was quite repeatable

Reason for overheating could be a) bad thermal conduction/circulation; b) damaged main chip; c) damaged peripheral electronic parts

without schematic and with my limited capabilites in in-deep- circuit study a fix for option c) did not seem feasible to me. Same for option b) as the chip is a large QFP - replacement was not a real option for me. So option a) remained. As TV worked remarkably longer just without rear cover, I assumed solution could not be too far away.