I don't think there is a freeplay on Robocop (its not mentioned in the manual). On my upright, somebody added an external "credit" switch just for that purpose. The attract sound is controlled by switch 1-6: sound on is switch "off" and sound off is switch "on" (very intuitive ...) You can set it so one coin gives 3 credits (sw1-1 off, sw1-2 on, sw1-3 off, sw1-4 on) which might make it more tolerable.