Is my AMP800 Dead


I just bought a second hand AMP800 and I've plugged 3.5 to 1/4 cable into the input L & R into the amp with a pair of headphones plugged into the headphone jacks on the front.  


Not only do I not get any sound, I also don't see any of the LEDs on the front moving which is making me think the AMP itself is not working.  I've tried multiple input sources in both input A and input B; same result. 


Any other suggestions before I email the buyer to get a refund on a defective unit?