Alpha, Open Door- M v S b L

[rwalker192]

I have a bally alpha with open door error m v s b l, I have metered all the switches and they are all working correctly. The logic is jumped on the mpu and the bill validator and cash box switches are working.
So far I have swapped the mpu, backplane, new batteries,

Any suggestions on what I'm missing??

Thanks
 

[rickhunter]

The only thing left is the wiring then.  Most of these door switches are wired to a connector or two. I would trace the wiring to make sure there's not a problem on the harnesses.

[coolwavepic]

One other thing to check is make sure your MPU is PUSHED ALL THE WAY IN! Once you push it in, give it an extra push in once the MPU is seated. If the MPU doesnt make contact with all pins, these errors will pop up.

[slotdoofus]

If I'm not mistaken, I think the only door switch that needs to work in a home environment is the lower door switch. You can splice the 2 wires together on all of the rest of the door switches to bypass the door switches. On the cash can switch, there are 3 wires. I'm not sure if you need to splice all of them together to bypass the switch. I haven't tried it. I've spliced together all of the other switches, including the ones on the MPU and my machines have all been running great.

[rwalker192]

Thanks all for the suggestions!
So far I have spliced all the wires except the lower door switch and still have the same problem. From there I checked all the wires from the different switches for continuity and all tested good.
I guess what gets me is the error is for every switch on the machine yet everything tests good. I can't believe I have two cpu's or backplanes with the same problem.
I'm picking up another cpu and backplane tomorrow and I'll give them a try, if this doesn't do it I don't know what to try next.
anyway thanks again!
(time for a beer!!)

[rwalker192]

I don't believe it but I replaced the mother board and everything is normal! Two mother boards with the same error is unbelievable!
Thanks again for the suggestions.