Protection Mode?

[ovo]

I have not used my D200 for several weeks and when I put it back into my system the control screen would not wake up and remains blank .The red power light at the rear is illuminated but the amp is totally unresponsive to the remote power button. The small downward facing light under the front power button is not illuminated.

I have followed the suggestions in the thread 'Remote Not Working', but without success.The Devialet site suggests that there is something called "Protection Mode", but rather unhelpfully, declines to explain further.

Any information, or suggestions would be welcome.