Was playing STTNG and the left flipper will stay up, as long as there’s power. Interlock switch when opening the coin door immediately drops the flipper and, when closing the coin door, it flips back up, staying up.

The flipper assembly is in great condition, no issues observed, all left flipper fuses are fine, no errors in menu. If I disconnect the power to the small PCB that’s posted near left flipper, no flippers flip as expected. That PCB has one red and one green led, can’t recall what normal was — any thoughts or suggestions?

Thanks for all the suggestions, I really appreciate them.

So the flipper does not fire up when turned on, only when game starts or in the tests menu. In the flipper coil tests, left flipper power and hold both work as expected (meaning they come back down after firing)

In the switch tests, the left flipper button is stuck in closed which would explain the behavior but not sure why it’s stuck that way, the PCB is recognizing the button presses with an additional green led when pressed (pictured below)
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Also, the switch test itself shows the press in the menu, via the small square in the lower right corner of the matrix (also pictured before/during press).
696532C9-DB2F-4EFD-A8ED-4093BF1FE19B (resized).jpeg283C59C4-5203-4CF3-AECE-EE1063EAC864 (resized).jpeg

EOS switch test is working as expected too.

Based on the suggestion above, the opto board, on the right flipper, looks like nothing is stuck or not clearing, last pictures before/during right flipper press.
68DB79B1-BDA2-4A9E-8AF2-082A959E58EA.jpeg49C6B046-9257-49D5-8D6F-6442877931AF.jpeg

Based on this info, does it lead more to transistor? No fuses blown, confirmed

Solved!

It was the magnet alignment on that left opto board... and all I can say is WOW is that touchy! Millimeter adjustments on that magnet and the problem solves or reverts...not a great design considering it’s not actually attached to the board itself.

I’ll definitely be replacing that now.

Big thanks to everyone’s help... love this amazing pinside community!