Sharp aquos 70"

as suggested, try the "master reset" (sequence is something like... set unplugged, hold down channel up and volume down while plugging set back in). This should force the set on. The error code that you are getting usually relates to a problem with "starting" the backlighting. It can be an issue with the power supply OR an issue with the LED backlights. Depending on further tests, one is a card replacement, the other is a "major set disassembly" (which most users and repair shops won't undertake because of the cost / time involved and chance of damaging the panel during the operation... but it can be done).

you likely have a panel issue. :-( It is usually caused by a bad tab driver / tab bond on the side of the panel. It can't be fixed but it can be potentially "saved" and operate again with a "normal picture". You need to try some further "testing". With the tcon cables connected, you need to disconnect a small ribbon cable in the bottom corner of the panel (there is one on each side). The ribbon cable connects the side boards to the bottom boards (small long thin boards along the bottom and side). Depending on which side is disconnected, you may get a picture happening, if you are lucky. The screen may be slightly darker on the side of the disconnected cable, along with some other visible screen "issues" (ie. lines, etc). If you repeat the "test" with the opposite side, it is unlikely that the set will start up again. Basically, this indicates that your set has a problem on the side that the disconnect cable allowed a picture to show. You then have to do a "delicate operation" to remove the tab driver / bonded cables along that side of the panel.
For more information on how to "save" your set , go to badcaps.net. Its has a forum there for DIY help on TV's and other things. If you search, you find lots of posts from people who have "saved" their set from the dumpster. This is the only way to fix the sharp 70 in sets with this type of problem (ie. tab failure). Good luck.