Tonearm Nightmare

I have been trying to set up my Spacedeck with Ace/Space arm and have encountered a problem that has me totally clueless. The tonearm pulls back to its rest (away from platter) with significant authority even with anti-skating disengaged. It is impossible to cue the arm as it moves away from the record immediately. I'm sure there must be some big (and perhaps even obvious to someone who knows what to look for) issue that is causing this. I have not set up an arm before but have tried to gather as much information as possible to guide my efforts - I even watched Mikey's DVD twice!

If anyone has any advice or suggestions, I would would be very appreciative.