As a new owner of the 7400, I was having a problem with audio drop out. So I did a search and found some archives that reported this same problem. A little further checking with a friend that works in a Marantz dealer found a 6 page technical letter covering a batch of model 7400 serial numbers. The Audio "drop outs" occur when using optical digital cable inputs ONLY. And only on the 7400. Something about a bias setting in a capacitor. If you have the problem check with your dealer! Sounds like they have a replacement policy.