Check the harness on the underside of the mother board. Drop the belly pan and make sure all are latched. Also check the harness for channel 12 at the patch
I shut down-remodeled and moved the console 2 feet to do floors. When I powered up channel 12 does not light up or pass audio. I swapped with 13 and 12 works
Easy way.? LOL That is the easy way. I hate those things so much I bought the LED replacement modules for my own console, but got unlucky and got a bad lot