Samsung led tv, doesn't power on, no stand by light on front, makes clicking sounds........is this definitely the power supply?

Please un-plug the cable between the main board & the power supply board, apply AC power to the TV, if the back light come on, that means the back lights & the power supply are OK, then you need to replace the main board; if the back lights does not light up, mostly the back light LED strip(s) is bad.

Main power supply regulator board fault. Check and replace it. If you wish to get more details visit the site linked here. http://electronicshelponline.blogspot.com/

ORIGINAL SAMSUNG BN44-00445A BN4400445A POWER SUPPLY FOR PN59D550C1FXZA PN64D550C1FXZA
Original Samsung BN44 00445A BN4400445A Power Supply for PN59D550C1FXZA...

Here is what to check when your TV is turned on, power light is ON, but no picture is seen or sound is heard:

1 - Be sure the component you are using (Xbox, Cable, SAT, ROKU) is turned ON.
2 - Check to be sure all cable and cords are securely connected to the TV inputs and component outputs.
3 - Make sure you are on the correct input as some TV's will show a black screen if there is nothing connected to that input.
4 - Unplug the input you are trying to use from the TV (such as an HDMI Cable) and plug it back in.
5 - Check for signs of damage on all cords and cables from the TV to all components.
6 - Make sure the TV is not in ENERGY SAVE MODE, press the button on the remote control to go back to normal mode.
7 - Unplug the TV for 10 minutes to see if there was a temporary one time issue with the TV.
8 - Disconnect the TV from power for 2 minutes, then when plugging it back in PRESS AND HOLD THE POWER BUTTON ON THE TV FOR 10 to 20 SECONDS to try and force the TV to reset.
9 - If after checking all these different issues, you may have a Faulty Power Supply Board, A Bad Capacitor on the Power Supply Board, Loose Wire Harness, or Loose Ribbon Connector in the TV itself.
10 - Most likely when a TV has the power light ON but NO PICTURE and NO SOUND, it is the Power Supply Board that has failed.

BTW, here are solutions for you to play iTunes movies on Samsung smart TV

Just search for the site named Electro-help. It has details about repair. I assumes that you're somewhat sound in electronics. You can get details there. Search for the site by Google

if just an stand by indicator at the front panel check for bulging capacitors at the power supply board.

Yes,the LED power lite on the front panel stable?Yes,mean the DM power supply board is good.LED power like blinking,mean the DM power supply board is dead.DM power supply is good,still making that clicking sound,when turn on.Mean ur Blast board is dead,that the board that help to light up the projection lamp.

Now,u plug in the tv u get a solid red standby power red LED light in the front of the LCD panel right?When u push the power button on the remote u hear a clicking sound?Only one clicking sound,not the power supply board problems.It the Tuner board problems.But u can make sure it the power board problems or not.By taking the tv aparts check the power board,that board where the a/c power cord goes into it.Look all around the power supply board check for these leakage capacitors,they alway bulges up it top or puff up it top.No bad leakage capacitors,then it not the power supply board problems.

replace the lamp only takes few min make sure you get right one for model of tv the LAMP MODEL number will be on OLD LAMP the tv will work and sound will come back hope this helps