Sansung model 56 Inch hpl5663w first had a buzzing sound the tv repair man said it might be a color wheel but the tv played well except for the low buzzing sound . then one night the picture went black and...
Sorry for the late reply, I'm offline upon purchasing my service.
You have said that you can hear a low buzzing sound before the unit gone to subsequent shutdown and the lamp blinks green(meaning that the unit try to turn on the lamp for consecutive attempts but not generally mean that the lamp itself is faulty.) and the temp led light come on.
As a matter of fact all the information you have mentioned linked to the symptoms you've encountered right now. A low buzzing sound might be caused by faulty FAN inside the unit that trigger the error code (blinking of the standby/temp led light) and turns off the unit automatically due to thermal protection circuit.
However, the technician might be true also that the buzzing sound came from the faulty color wheel. To confirm it, you have to verify where the buzzing sound came from. Color wheel is in front of the lamp assembly. Faulty color wheel can produce the same symptoms you've encountered right now but most of the time, it shows 3 blinking led light at the front panel (Timer, Lamp, standby/Temp).
I would advice you to open the back cover of your unit, fixed the lamp door safety switch with the tape to make it in closed position( if it is on open position the unit will not power up), and then turn on the unit and observe the fans if will spin or not, and check also where the buzzing sound came from before the unit gone to shutdown.
I've suspected that the fault came from the fan based on the led light flashes. Please let me know what you will discover after following the steps above to verify where the exact fault came from. Also, let me know the exact status of the led light at the front panel, (Timer, Lamp, standby/Temp ), which of them lit solid/blinking, it will help us to narrow the caused of the symptoms.