Short Answer:-Choose the 'DAC' mode of the 'Audio Path Select' function (hold down 'Set Locate' and press 'All In', the display will change from 'IN' to 'DAC'). This seems to bypass some sort of digital routing logic that causes the problem. Long Answer:You can reproduce an audio dropout on demand by pushing the stop button on a blackface ADAT. The helical head on an ADAT has two stop modes - stopped with the head rotating and stopped with the head not rotating. Pressing the stop button would cause the ADAT to toggle between these two modes and apparently change interior audio routing in such a way as to cause a brief audio dropout. Further experimentation with some of the hidden functions concerned with the converters yielded positive results...there is in fact a way to override the internal audio routing logic of an ADAT such that the audio is always monitored from the same source (hold down 'Set Locate' and press 'All In' for the benefit of anyone with a similar problem.)