Zeta Tonearm Troubles

Recently purchased a used Gyrodec w Zeta tonearm. The tonearm connection (at the bottom of tonearm which goes to phono amp) appears to be a 5 pin DIN but the new cable I bought (Audioquest Wildcat) does not seem to fit. It requires a huge amount of force and doesn't feel secure after all that effort.  Does anyone have this tonearm who can speak to this issue? Am I just not applying enough force? Is the 5 pin connector at the bottom of the tonearm not a standard 5 pin DIN connection? 

Please help