Tc-p50st50 flashes 6 error code

I have a 2012 Plasma that will go into a lockout with 6 error code flashes, I can reset it using the power button on the tv, it will sometimes work for a week following the reset before doing the same thing, the next time the reset may only before a matter of seconds. I have checked the boards for signs of failures with not obvious problems. The troubleshooting for 6 flashes states that the most probably fault is the sc board, with the next most probable being the “a” board. I am uncertain how to determine with certainty which board is causing the problem. I did check the boards for loose screw grounding connections, there are signs of arcing in a few locations. Any help on how to proceed is appreciated.