moon patrol fire button not working

tkidd

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Moon patrol is working me over. Everything works but the fire button. I have redone the wiring harness and even put the moon patrol board in another Jamma cabinet with an adapter, same problem. Any ideas where to start will be a big help. Thanks
 
Moon patrol is working me over. Everything works but the fire button. I have redone the wiring harness and even put the moon patrol board in another Jamma cabinet with an adapter, same problem. Any ideas where to start will be a big help. Thanks

Got a logic probe?

Check the machine in 2P mode, if it jumps on player 2 then check the resistor pack RA2 since that seems to be tied to P1 inputs... RA1 is for P2 inputs.

If the resistor pack is good then it's time to pull out the logic probe and check some chips. Luckily, it looks like there are only 2 to worry about (at max). The Jump button is tied to pin8 on either 1D or 1C (both are 74LS244). 1D is for the P1 inputs, 1C is for P2. I don't have the data sheet on hand right now for the 244... but looking at the schematic I'd be willing to bet that pin12 on either of those chips is the output for their pin8's... since all other inputs are working, you should be able to see what the controls are supposed to be doing by looking at the working controls, then compare'ng it to pin8 and 12.
http://files.arcadecontrols.com/details.php?image_id=1792<-- Page 10 for the inputs.

EDIT: Changed link and pin numbers when I noticed I was looking at Jump and not Fire.
 
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With power on, I would put your logic probe on the pin of the edge connecter for the button that is working. It should be high and then go low when you press the button.

Now do the same thing for the button that is not working. If they both behave the same, your problem is on the PCB. If they behave differently, the problem is in your harness or adapter.
 
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