I have a Hafler DH 500. The amp has powered down and the power switch is blinking red. I can turn the amp off and let it cool for a while and it will again be operational for a while and then it goes down and the power switch blinks.What is happening? I also need a owners manual for the DH 500 . Thanks Jim.
You can have John Hillig at Musical Concepts repair and modify your amp. He does first rate work. Go to his website musicalconcepts.com.
Your fan may have failed. It sounds like it may be over heating. I'm not sure I don't have the DH-500. You can download the manual here:

You will need Adobe reader to view it.

Good luck,