Hello and welcome to justanswer.com my name is XXXXX XXXXX I'm here to help you with your TV problem.
That does signify a power supply problem but are you able to call the technician back to your home to fix the problem properly?
Are any of the three front lights (standby, timer, lamp) flashing please?
Do you remember a popcorn burning type smell when it started acting up?
Here is the power board inside your TV
Can you identify it and look on the top for any bulging capacitors which will look like this
Here is the ballast board which drives the lamp
Also check the capacitor on it.
If you see any bulging capacitors and you have TV repair experience you can change the parts yourself. If not then I recommend you change the boards. It's common for both these boards to cause problems so to save you the shipping charge you may want to order both.
Since the lamp is new then it should be ok. If it wasn't, then the three LEDs would flash.
Once you get the TV working please check to make sure that all the cooling fans are working. If not, you can order from here