I have read through so many of the posts on door optics and believe I have gone through everything that it could possibly be and still am having issues. Below is a list of things that I either know now or have done to troubleshoot this:
1. Swapped MPU.
2. Ran new MPU on known good machine, ran clear and denim chips and played the game on different machine with no issues.
3. Changed out motherboard from donor.
4. Replace optics.
5. Read out both emitter (on door)9VDC, should be 5VDC and receiver (Cabinet) 9VDC. I think the 9vdc at the door is a problem, that is what led me to swap MPU and then motherboard.
6. Reseated all connectors on mother board.
7. Reseated all connectors above MPU.
8. Ran the door optics test. When door is closed code remains 13......0. it does not swap rapidly between 13....0 and 13.....1.
9. I can load coins with the comparator and win credits and credits do not clear once door is closed. I can continue to play with credits earned from loading credits with the comparator button.
10. Comparator never accepts coins.
11. When I have tried to pay out I received multiple codes from the hopper, 3100 and 3200, neither of which would reset with the door open and closing.
12. Candle remains blinking signifying the door is open.
13. Jumpered the optics connectors and gotten it to work correctly.
14. Placed the optics facing each other with not luck.
15. Swapped know good optics from another machine no luck.
16. Swapped optics from broke machine into known good machine and they work great.
All throughout this troubleshooting, on occasion, I am able to get the optics to work. I have not been able to successfully duplicate what it is that gets it to work correctly, whether it is after I reseat a certain plug, wiggle a wire, change alignment on the optics =, oh and yes I have lined them up using tape and the like as noted on many posts with no luck.
I am not sure where to go from here. If someone does know which particular plug on the mother board or above the MPU contains the wires that come from the optics so I can read continuity and jiggle them, chem pins etc, I believe that is where I am at now.....freaking gremlins.