Did you see if an interference source might have been introduced? I have been having similar problems as you for the last 2 weeks, I noticed cracking a month ago, but it worsened 2 weeks ago to include popping and dropouts.I finally checked the AVS forum last weekend and noticed your posts. It was your posts that made me think I had introduced an interference source, particularly the bit about the repair shop not finding a problem with your receiver. So, I wondered what had I put near my stereo to cause such interference?
The answer was sitting right next to my stereo center. I have a severe disability and use an electric wheelchair (w/c) to get about. A month ago some friends gave me a broken down w/c to turn into a backup w/c, I parked it right next to my stereo center. This "new" w/c came with an automatic battery charger, thus no more having to make sure the charger was turned on, so I started using it. Two weeks ago I got the idea that the charger would be easier to get to for my attendants if it was on the seat of the new chair instead of them crawling between the w/c and the stereo center, it was. However, this now put the new charger level with and within 3 feet of my cd player (which exhibited the worst problems), my other components were stacked above it. Sunday I saw your posts, which started me thinking. Monday morning I moved the charger well away from the stereo center and then turned on the receiver - clarity, no crackles, no pops, and no drop outs. I am having frequent "access errors" with pandora, but I notice the spot I moved charger to is only a couple inches from a cat5 cable which runs to the pc I'm trying set up as a music sever. I'll test moving the charger away from that cat5 cable next.
So, Nicodemus22 thank you for your posts, they were a big help. I think you should inspect your stereo center area for for some interference source, and don't let the innocuous or mundane stay your scrutiny. Good Luck!