Ok so what you have here is a bad "BAL board" (main board) this is kinda like the motherboard of the computer, it does most of the work.
This is indicated by the 7 blinks. The bad news is the only way to repair the tv is to replace this board. The part number for this is A-1763-462-B. Looks like it runs around $160 for the part.
Now about your question, can you fix this yourself? I would say it depends on your skill level. To replace this board, you have to take the back off the tv, remove all screws and wires from the board, pull the board out, put the new board in, attach all wires and screw it down. Then the biggest part is you must remember to do a software update when you turn the tv on for the first time. If you forget to install it and turn it on, you can corupt your brand new board and have to buy another one.
So if this is something you want to try, let me know, I will be more than happy to help you with any aspect that I can. If not, a tech normally runs around $200-300 for labor.
Please let me know if you have any other questions or need any other information at all, if you do please use the reply to expert tab. If this was all the info you needed then please remember to rate me before leaving. Please do not hesitate to ask anything, happy to help in any way I can!