Shelter 201 hum

I just installed a Shelter 201 on my SME 3012/Garrard 401 combo.  Disappointed there is a far amount of hum present.  I just removed a Shure Type V which had no hum at all so nothing was changed but the cartridge.  I checked all leads and everything looks/feels fine.  Any ideas out there?
Remove the mounting screws and let the cartridge drop down a bit so that its not touching the head shell. Leave the wires attached. Still getting a hum? 
FYI: The Shure has a ground tab on the right channel ( green pin). Sounds like you now have a grounding problem. If you have the tonearm ground lead hooked up , leave it off and see if the hum goes away. If not try to hook it up to another ground source.