O.k then I`m afraid that it looks like you may have a defective main board.
Strangely enough on this model TLX-04243B , it is cheaper to replace the whole control box than the main board alone.
The control box has pretty much all the boards in your tv ,including the main board mounted on it ,so it would be hard to miss in this case , this control box cost around $65 to buy.
Not sure if you were into repairing this yourself but here is a link where you can see one version of it for your tv ;
There are some 3 or 4 versions for your model so if you are to order one , do it by phone at the number listed on that page , they will have questions for you to find out which versions is in your tv , just have the back cover off before you call them.
In a repair shop , you may be looking at a $200 repair .
If you go for the repair shop option then click on the link below and enter your zip code ;
This will give you a list of repair shops in your area.
You could give a call to different shops in your area to get an idea of their rates , this is a bit like buying insurances , it pays to shop around.
Wish i had better news and an easier solution for you today but i hope this help and I will be in standby if you have any questions.
Thank you and please take the time to rate my answer if that answers your question and you can still reach me here at anytime after this chat is closed if you have other questions.
Please note that from where i`m sitting there is just so much that i can do and if you are going to rate my answer below O.K service then please do not rate at all , just let me know.