Diagnosis
Three red blinks is a definite error code. It means a problem with the TV's internal power supply or main board.
How to Fix It
Unplug the TV from the wall for 5 minutes. Plug it directly into a wall outlet, not a power strip. Try turning it on. If the code returns, the internal power supply (PSU) board has failed.
If That Didn't Work
A failed main board can also cause this code. You must open the TV and test for DC voltages from the PSU. If all voltages are present, the main board (EAX67177504) is the cause.
Heads Up
Do not ignore this code. Repeated attempts can damage other boards. This is a component-level repair. Call a technician if unsure.