Since all the flippers stop working, I wonder if the Flipper Enable Relay is de-energizing. It should energize and stay energized as long as a game is going on. If it drops out, it shuts off all the flippers. The IC at U4 and transistor Q15 should be holding it on.

Could the diode on the coil of the left flipper be backwards? Maybe after the flip, the coil voltage collapses and goes back up the line to screw with the MPU and make the Enable relay release?

Just a guess. There is some useful information about Bally/Stern flipper configurations here: http://stevekulpa.net/pinball/bally_flipper1.htm

That's really a puzzle. The coil has a schematic right on it, which you seem to have followed perfectly. Diodes are the right way round, and it seems like all your wires go to the right places. If the EoS switch is shorted, I'm not sure that it would instantly shut off all the flippers, since it'd basically be behaving like the EoS was just misadjusted. It does appear to be shorted, though, and you'd want to fix that right off.

Now watching the video in slow motion it seems like it sparks down near the pawl. I think there is supposed to be fish paper on the EoS switch or a little rubber pad on the pawl arm that opens the EoS switch up. Without something to insulate it, I think you may be grounding +40V into the pawl, which might be causing a problem.

that_is_awfully_close_(resized).JPG

That's also a strong possibility. It is really close to where the spark happens.

vid1900 has the sharpest eyes.

You may still want to check that solder joint on the EoS switch for a short. Also, I'd still make sure that the pawl isn't making contact to the actual EoS switch leaves. The plastic spacer should open the EoS leaves without any metal to metal contact. Could the EoS switch have completed a circuit through the leaf with the spacer, through the pawl, to the lamp socket? I wonder since the lamp touching didn't seem to be a problem until the flipper plunger tried to pull in.