@OP, its a shame that unit went out on you should’ve last more than 4 years. Marantz Usually are pretty reliable, but with that said it does happen even to the best of the best. My Son and I just got each a Yamaha Advantage AVR, their a1080, my Son had to send his back after about two weeks his unit was getting this very loud Popping sound Randomly. I just happen to be over at his house we where watching a NFL game, lo and behold the unit did it when I was there when I say a very loud Pop sound it was Loud! So he called into Yamaha got a tech on the line went through a hard reset, took about 10 Minutes and it did it again. Yamaha Tech recommendation was to send the unit back to Amazon for a Exchange or refund. I recommended that he get a new one from Crutchfield cause they have a 60 day return. He did order one from them, his new unit going strong that was back in October. We did a Search and come to find out some Yamaha units with the Advantage line has had some issues with Power Transistors at the rail going bad or Defective but only one or two of them power output Transistors that is. I posted this only to make light of even Yamaha with their very good Reliability record, has Quality control issues to at times.