I work at a mall kiosk where we've repaired too many to count.What I found not sure if it helps but I had the same issue with the crackling noise. What fixed the issue for us turned out to be the charge port connector. It turned out since it was a new charge flex we replaced since the connector when they're new doesn't have as much give or hasn't been broken in. What I noticed is that it being stiff it caused the connector to slightly become raised/lifted from the connector. What I did was not put the sticky part underneath the flex cable down onto the mobo and simply connect the cable. Voila it all worked no static. Happy customer, hope this helps