When the ADAT is displaying peaking levels on channel 1, that usually means there is a sync clock problem.Make sure the ADAT is set to external sync mode. (On the original ADATs, pressing the Set Locate button and Digital Input button toggles the ADAT between Int sync mode or Dig sync mode.)Verify the session sync settings and also check that the sync cables are installed correctly and that they are the proper length. Sync cables that are more than a couple feet long have sometimes been the cause of these kinds of problems.