Our TV will get some red flashes and then go blank. Sound still goes for a couple more seconds and then the TV shuts off. The light blinks 8 times. It is pretty consistent. We can leave it off for a while and it will go through the same routine.
Unfortunately, you are describing the classic symptom of a bad picture tube. When the tube warms up a short developes in the neck of the tube, usually between the heater and cathode and this forces the tube to go full on, giving a bright flash of the color of the defective tube. The computer senses the extra current flowing through the flyback (high voltage) transformer when the tube is shorted and shuts the set down. The only solution is to replace the picture tube, but the Sony tubes are relatively inexpensive (about $175 for the entire tube assembly including sealed coolant) and they are very easy to replace and realign, but of course this must be handled by someone with experience.
Usually answered in minutes!