goolge search for troubleshooting tv power supplies reutned several good videos
https://www.youtube.com/watch?v=qxG3hmmvkJs
i was not getting any standby voltage on power supply board so decided to spend $25 on power supply on ebay before paying a tv repair ship or buying a new tv
replaced board and TV is working.
details
remove the back cover. easiest to have it lying face down on the floor
about 2 dozen screws. 3 sizes. all Phillips head
disconnect ribbon in lower right corner of power supply board (blue circle) and check for any voltage on the pins. i did not get any voltage on any pin so assumed bad board.
disconnect 4 other connectors (red circles). can do by hand.
remove 5 screws
replace board.
