After having done some additional testing, I found the following to be true (apologies for the wrong info in my original post):
– it actually DOES NOT crackle when bypassed!
– it also does not crackle within firs 2-5 minutes after being turned off for a while.
– it crackles more when a new algorythm is engaged at first, and then ceases (not completely, though)
I think I may send it in for a repair after all…this is beyond me. I have visually inspected the solder joints around all plugs and they seem fine. I have also once agin unplugged the ribbon cable from the front board and reconnected it back. That did nothing….