coin door wiring problems (picture heavy)

[superpomme]

I have modified an old jamma cabinet into a mame machine, but am having some issues wiring up the coin door. I have done a lot of searching online to see how other people have done it, but everyone else's coin doors seem to look, and to work, different from my own.

I know very little about electronics, but am happy to experiment. I have the wiring for buttons soldered to a usb controller which works great, but when I was experimenting wiring the coin door up to it it kept ruining the controller ( im on the second one now, and if i try it it stops that button from working ever again, eventually killing the whole controller. I know this is a stupid way to do it, but with my limited electronics knowledge that has been the only way I have got stuff working).

My coin door is separated into two parts. The "coin validator" and the "credit control unit". It needs to be wired up to 12v to accept coins (just passes them straight through otherwise).

Heres a rubbishy paint drawing showing how they connect:

  ,

 and this is a picture of the two devices themselves. Unfortunately the writing has been rubbed off the credit control unit ages before I got it:

 

This is a picture of the coin validator explaining what the individual wires represent:





To get it accepting coins to test it, i simply spliced the wires labelled 12v and 0v to a pc power supply (but now it is wired up to a charger so that I could take it away from the arcade. This starts it working, and if I put money in, the coin validator collects them properly, and then the credit control doodad clicks (it clicks 5 times for a pound etc - so it is recognising the amount of money being put in).

This is the credit control unit itself:




Coming out of the credit control unit are 4 wires (two of which are connected) leading through to 3 crimped connectors (which originally ran through to the jamma wires. I took this all apart in premature haste a year ago, so unsure what lead where).

A picture of that is here:

 

ignore the wiring coming off the white wire here, that was just part of an earlier experiment on my part.


Any help with this would be much appreciated - everyone else just seems to wire it up like a microswitch, but theirs all look different. I have tried searching model numbers etc for the devices but no luck. I am just looking to wire it so that coins in twigger a button that i can then use as the credit button in mame.

Thanks for any help or advice with this, and please ask if I can make anything clearer

[BobA]

Can you use a multimeter to determine if voltages change when you insert a coin?  You are only dealing with 3 wires so measuring the voltage with reference to each other and then when a coin causes it to pulse may determine what the outputs are.