At this point I'm just looking around various forums and noticing that this is not an uncommon problem and hoping for an easy fix. For now I'm just listening in SOURCE DIRECT and hoping someone will come around with an easy fix that doesn't involve me DIYing inside the carcass.
I'm also experiencing the same issue with my Marantz PM6006. I brought it to the repair shop 3 times, but the same problem is always coming back. I'm not sure what the technician did last time, it worked perfectly fine for 3 months and now the issue is intermittent. At this point, it's useless to bring it back to the repair shop since the same issue always comes back after few months.