This amplifier was returned to with the following explanation for the return:
"Item was tested and it makes a humming sound and doesn’t send sound to speakers. The humming likely indicates a problem with the power supply, grounding issues, faulty internal components (like capacitors), or potentially a damaged input circuit."

The buyer did not properly package this for the return shipment and the rack mount ears were bent during the return shipping as shown in the pictures.  This still powers on fine but I am not able to test it further and so I am offering it AS-IS for parts or repair.  

D4-3
fdk 80218258