au-9900 suddently in and out of protection mode

Listening to my au-9900 today the amps protection light suddently started to blink between green and red, and the sound was coming and going too. This is the first time this happened since I got the amp a year and half ago and naturally I’m really worried. It's the only au-9900 I've got!

The only ‘technical’ action I was able take was to measure the DC offset with my multimeter as described in the very good AK thread on that subject. One of the channels (the right one) measured around 50 mv and was rising just before the protection kicked in.

Now when the au-9900 is cold again the projection stays ‘out’ but I predict it to kick in as the amp gets warmed up.

What am I looking at here? Will a bias/DC offset adjustment solve the problem (next question will be how to do the adjustment)?

Peter, Denmark

Hi Peter, sure someone else with much more knowledge will be along anytime now to help out with yer issue, hopefully nothing to big, them things was built like tanks but sound beautiful!!!! Good luck