Here's is what you need to look for when describing a problem for troubleshooting purposes:
0) What model is the TV (you've covered that)
1) Does the TV respond to command to turn on?
(yes - continue; no - 70% bad power, 30% bad main board)
2) Once it responds (clicks), does a front LED or other indication show that it turns on? It's OK if there's no display.
(that can be model specific and is not certain indication for anything until known what is specific for the model)
3) If such an indication comes up does it remain on until you act or does it go off by itself?
(Stays on - power supply likely good; turns off - power supply *may* be good, but not certain)
4) If the power indication stays on by itself can you make it go off by pressing the power button or do you have to disconnect from AC power?
(responds to power off - 90% power supply likely OK and 90% OK main board; does not respond to power off - 90% bad main board)
Here is a link for test/repair of the power supply of your TV, hope it would help: