you can download a manual for it from MEI's website (MEI=MARS corporate name) & it will show you how to program the 'mech to accept coins, but if the detection coil in the electronic coin-receiver is defective, then the only fix is to replace the coin-receiver & retune/reprogram it for new coins. this is all covered in the manual.
I have the manual open in front of me. All of the DIP switches are set properly. It is accepting dimes and nickels correctly, and even dollars. It just spits quarters back out.