So.. the questions I have may not help but they are worth asking. I know you have talked with tech support but they can not diagnose wire troubles. Have you tested the wiring for faults, partial shorts or ambient voltages yet?

We have had one system that acted similar. But it was in a high voltage electronics location. We found that cleaning up some wiring and replacing the cards made a huge difference.

Oh and your second to last sentence was not necessary. It may be a problem on your system but not everyone that owns a 7200 has issues like these. :thumb: