Hi @walterscot75363
Just checking that you have proved that the wall outlet that the TV is connected to is working OK?
Do you have a DMM (digital multimeter)?
If so disconnect the power to the TV and remove the back cover from the TV and locate the STB voltage reference point on the power board (see image below).
Reconnect the power to the TV and use the DMM to check if there's 7.5V DC at the reference point.
If there is 7.5V DC then it may be a faulty mainboard.
If there is ~11.8V DC then again it could be a faulty mainboard.
If there is too low a voltage or no voltage, disconnect the power to the TV and then disconnect the mainboard-power cable at the power board end ''only.'' Reconnect the power to the TV and check the reference point again. If it is still the same most likely it's a faulty power board.
Replacement boards have been known to be faulty. Also did you replace both boards at the same time or one at a time?
''***Be safety aware*** when testing as there is ***exposed lethal AC voltage*** on the power board.''
[image|3111807]
(click on image)