I've noticed several CDS problems:

1. Communication sign on C1SUS model turns to red once in a while. I press diag reset and it is gone. But after some time comes back.
2. On C1LSC machine red "U" lamp shines with a period ~5 sec.
3. I was not able to read data from the SR785 using netgpibdata.py. Either connection is not established at all, or data starts to download and then stops in the middle. I've checked the cables, power supplies and everything, still the same thing.