Power Dsine 3512 p/n 3512/AC 2 Port Power Over Ethernet (POE) Midspan

This came from a community college.  It powers on but it has a loud hum.  It sound to me like it is coming from the fan but I don't know for sure.  I haven't been able to test it beyond that but we do warranty it for 30 days.  This will come with a power cord but no other accessories are included. 

C5-6

fdk 80213218