I've been using my Fireface 800 without so much as a hiccup for almost a year now, but suddenly it seems to have a serious issue.  I had turned off the unit over the weekend, and upon turning it back on the signal LED's lit up with a cyclic clip on all inputs.  None of the connectivity LED's lit, only the preamps.  Has anyone encountered this previously, and if so what's the source of the problem?