Help Classe CA300 flashing Green Light

ok, reporting in.
If I set the multimeter to measure for DC and I pull the digital cable out of the preamp (it is now coming out of the DVD player), have everything on and press play on the DVD so the bits are coming out the cable, and place both leads on the RCA plug of the digital cable- the reading is 0.00
what does that mean?

Means that my theory is apparently incorrect regarding DC coming out of that player. However it still sounds like the Classe is seeing DC on an input - that pop noise & triggering of the protection circuit is telling you something. I am still trying to figure out the whole picture though (?what is connected to what & exactly what this whole system looks like?) so at this point in the troubleshooting sequence a phone call would be the best bet regarding efficient usage of time.
But over the weekend I thought of another thing to try. Reinstall the Classe & put everything back the way that it was originally, except don't plug the DVD player interconnect into the (??Adcom pre/proc is it??) digital input? Make sure the that tuner input still plays. Now switch to the DVD input. Do you still get that pop & triggering of the Classe into protect mode? If so, then apparently something in the pre/proc's digital input section has failed. Could also try this test with a shorting plug inserted into digital input (or a cable with its' tip & ring clip-leaded into a short circuit).

Thanks so much, Bob - I have sent you a detailed email. I am learning a lot on this exercise I must say! Cheers, QOv