Quoted from Robotworkshop:You are missing the two odd retaining brackets that are specific to the Wico coin door. They seem to work better with the plastic coin mechs.
Unfortunately those are extremely hard to come by and it took me years to find a pair so I could finally add coin mechs to my Pinbot.
If someone wants to send me one, i'll draw it up in solidworks, so it can be 3d printed. Then i'll send it back.
Bob