O.k then from all this I can tell you that everything points to a defective main board part # ***** and if you are into this then you can get that bard at the link below for $150 ;
Let me know and i will help you along if you wish to look into repairing this yourself
This is Plug&Play ,no solder or adjustments and if you or a friend is handy with a screwdriver and can remove the back cover then you can do this yourself, no special tools required.
If that is not your cup of tea so to speak then to have this repaired at home could cost you around $300 parts included and perhaps $50 less if you take it to the shop yourself .
If you need to find repair shops near you then look at the link below and enter your zip code ;
This will give you a list of NESDA member repair shops in your area.
This list may be limited though and you may find more by simply using the yellow pages or simply google "tv repairs" and the name of your town .
You could give a call to different shops in your area to get an idea of their rates , it pays to shop around .
Let me know if you have other questions and if not then please do not forget to rate by clicking on the star icons at the top, then click on Submit so i get paid for my time helping you .
Also note that it will not close this post , you can come back here at any time if you need further info or help .