I know it’s been a bit since this post, but I just finished putting one of these together for my board and #3 and #4 doesn’t work. 1,2, and 5 work great. 3 and 4 pass clean signal but as soon as I hit the switch it kills everything. I replaced 3 and 4 and it still does the same. Could it be the jacks? I went back and re-flowed the solder on the jacks but still nothing. Any thoughts? The LED’s work but no sound when activated. I will post a pic shortly.