Dual CS508 generates hum

Decided to pull some equipment out of storage. Had an old NAD 302 amp in great condition along with some PSB speakers. Connected my ipod and the sound was so beautifully warm. Decided to connect my Dual CS 508 turntable with a Grado cartridge and everytime I went to play anything I got a hum out of one channel. Thought it was amp but tape deck works fine, tuner or ipod but for some reason this turntable produces a hum which i don't recall (it has been years since it was used) I made sure it was grounded and it was. I tried connecting the turntable to my Mac to transfer some LPs to my computer and I received the same hum. Anything I can troubleshoot? I was thinking of picking up another cartridge to see if it is the Grado. I got rid of most of my records, but have a small selection that I want to put on computer.

Thanks