Audio Systems: NAD 2200 Cuts out at high levels

Question
Hello,

I have a NAD 2200 that when I use at low levels the amp works perfectly. As soon as I turn up the volume I hear a click, and the amp shuts off and the red light comes on that indicates the unit has gone into protection mode.  If I turn the volume down then the unit comes back on.  You previously answered somebody with the opposite problem (not working at low levels) that:

"The output transistors have a heat transfer silicon grease in between the transistor and the heat sink they are mounted on.   This grease dries out over a few years and the heat transfer is diminished causing the transistors to heat up and kick in the protection cutouts."

Am I encountering a similar issue or is it something completely different?  How difficult will it be for a tech to fix this problem?

Answer
In your case according to the symptom of going into protection mode with no more than a very low output is indicative of a short on the output; either a wire shorting to ground or a speaker with a shorted voice coil.  Check this by removing all speaker connections at the terminals on the back of the amp.  Reconnect them one at a time to see which speaker line is the cause.

Hope that helps.