Do you think it would just be the t-con board? I was able to do the video picture test without any fault and can get through the menu and everything looks and acts just fine until until the point in time when it starts to act up and flashes into the gray screen almost like static only with the vertical and horizontal lines at the same time scrolling across the screen

I have UN40EH5300FXZA I was try to use my Note 4 w/ MHL adapter on my tv when signal cut & couldnt regain As i opened phone end of cord i saw it had broke its connections, soldered back together and just as I finished my friend walk up picked it up, of course I had just finished and was trying to test the connection with my phone prior and I left it plugged into the HDMI cord. When he turned around holding it it arc'd out the wires causing lots of Sparks, TV flashed & then cut to Grey screen with horizontal and vertical lines scrolling across the screen. Now whenever I turn the TV on it has pristine picture in all the different video input modes however after 1 to 5 minutes my screen Cuts back into the grey mode with horizontal and vertical lines scrolling across the screen I am unable to control the TV via control panel or remote during this it then cuts to a black screen then through startup and repeats till I pull the power cord question is can you tell me what I need to replace?