My TV does not power on and the standby led is not on. The power cord is plugged in.

Connect the power cord to the power socket after you have completed all the physical connections. At this stage, the TV will enter Standby Mode and LED indicator is white. In Standby Mode, press the button on the main unit or on the remote control to turn the TV on.
https://elementelectronics.com/wp-content/uploads/2019/07/Smart-TV-User-Manual.pdf

Need to know how many times the led is blinking.

Try this link for more information

Re: tv kdl-55ex620 red light blink 8 times Do a Power Reset. 1. While the TV is off, unplug the power cord of the TV from the electrical outlet. 2. Let the TV remain without power for 60 seconds. 3. Plug the power cord back into the electrical outlet. (If the television is plugged into a power strip or surge protector, remove it from the power strip or surge protector and plug it directly into the wall outlet. If the issue is resolved, the problem is with the power strip or surge protector and not the television.) 4. Turn on the TV. 5. When the TV powers on and a picture is displayed, reset the TV to factory default settings.

• If the Reset message does not appear and the TV turns off and on, begin again from step 5.

• If the standby light begins blinking eight times, return to step 1.

6. After the Reset message appears, allow the TV to reset. Do not press any buttons on the remote control or on the TV and do not make any other adjustments for 1 minute. 7. Unplug the power cord from the electrical outlet. 8. Allow the TV to remain without power for 10 seconds. 9. Plug the power cord back into the electrical outlet. 10. Turn on the TV.

• The initial setup screen displays if the above procedures were performed correctly.

11. Follow the on-screen instructions to complete the initial set up. 12. Perform a system software (firmware) update.

Hello Peter, my suggestion is unplug your cable satelite (STB) conection.
Turn on the TV and see if there are changes or is still standby.
If your TV like normal after unplug satelite tv (STB) connection, you should check you STB.
If still not working, try to unplug AC cord from power line. Wait until led display indicator off, that plug again. If it still not working, i think you should call samsung technician to check you tv.
thanks.

No power to the tv at all?No,LED power light indication or no LED power standy light.The tv power supply board is dead.That the board,where it take in the power a/c cord plug into it.Tries websites like Shopjimmy.com,Ebay.com to buy a refurbish power supply board for the replacement.

The power supply board is dead.That the board,where the power a/c cord plug into it.Tries websites like Shopjimmy.com,Ebay.com to buy a refurbish power supply board for the replacement.

This is common problem with the PLTV-3250, the power supply DC filter caps go bad, 5vdc standby transistor and diode shorted out.
Check the power supply; look for bad caps with leaking/bulging tops, check to see if you have standby +5vdc at the power supply connector, the front red indicator will not be on if you do not have this +5vdc standby voltage due to shorted out Q7 and ZD4.
http://s807.photobucket.com/albums/yy352/budm/Protron%20PLTV%203250/

http://www.fixya.com/support/r5093881-lcd_flat_panel_tv_troubleshooting_guide
Power supply: http://www.google.com/products?rlz=1T4GGIH_enUS282US283&q=pltv+3250+power+supply&um=1&ie=UTF-8&ei=9lIDTL7XO4fcM7HA-Ds&sa=X&oi=product_result_group&ct=title&resnum=1&ved=0CCgQrQQwAA

check for the blown FUSE after the power cord.Check standby power section for a defective component.

The STANDBY light will flash if the television detects an issue within the television. Some of these issues can be resolved simply by following the steps below to reset the television.
If the issue is still unresolved after following all of the troubleshooting steps, service may be required . Please note the number of times the STANDBY light flashes and relay that information to the service center.

1. Turn off the television. Unplug the television power cord from the electrical outlet.
   
2. Let the television remain without power for 60 seconds.
3. Plug the power cord back into the electrical outlet. NOTE: If the television is plugged into a power strip or surge protector, remove it from the power strip or surge protector and plug it directly into the wall outlet. If the issue is resolved, the problem is with the power strip or surge protector and not the television.
   
4. Turn on the television.

call Polariod
replace 'box'
(their description, not mine)

bad power supply