Logically, if the problem arose after rebuild it would be something to do with rebuild. The cab switches look original, and can be ruled out. The pic below is a little difficult to see because it is incomplete - flipper bat shaft isn't installed. The only thing that jumps out in the pics provided is the EOS gap. It looks like the contacts are not touching in idle (again, little difficult to see clearly). EOS design is to be closed all the time, at rest....then the switch opens when the flipper is activated and reaches max travel. If there is any gap in the EOS at rest, it will never operate.

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I rebuilt my flippers on my Whirlwind last month which can be read about here with a few photos. https://pinside.com/pinball/forum/topic/system-11-flipper-rebuild-question-what-am-i-doing-wrong-photo-insid

After more time, I have determined that even though they are brand new, there is a thin film of oil that comes on EOS switches that prevents contact. In my case, simply taking a paper towel and wiping the area where the EOS contacts touch each other when closed fixed my issue.

I'm not sure this is your problem, but it would take 2 minutes to check and doesn't require disassembly.

Make sure the inner contact on the upper flipper cab switch is actually moving in to touch the outer contact when the cab switch is pressed

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