How do I remove the heat knife cassette?

I'm running a cd102 with a grafix heater cassette. How do I get the cassette out to replace a couple heating coils?

 

4 (Phillips?) head screws fasten the element casing to the knife housing. Remove plug from element casing, remove screws from casing, lift out. Then, remove the screws from the plug mounted on casing. You will need a special tool to extract the crimped pins from the casing plug.