Usually the cause of this is a bad coil. Try measuring between the middle and each outer lug while the flipper is held up (by hand, game off). If you don't have matching resistance on each side, that's your problem. Could also try just swapping the coils

Orange wire (bottom pic) looks like a cold solder, not sure if that makes a difference. Also can you show a pic showing the EOS switch with the flipper up so we can see the gap? If the gap is too small it can cause this in my experience.

+1 for bad coil.

I'm going with bad coil

Look closely and see if the tiny winding wire is broken from the eyelet

I'm also leaning towards a bad coil.

But, it could also be a bad connection to the upper half of coil. Where the brown wire comes into right tab in first photo -- it is obvious that it is making connection to the brown wire going to the switch. But there can be a bad joint between the brown wire and the actual winding wire. Winding wire is red wire seen on left side of 2nd photo.

My new to me Flash Gordon's upper flipper was machine gunning. As several others have mentioned a new coil solved the issue.

Marco Specialties and Pinballife are 2 of your bigger and better pinball parts places around. Can't go wrong with either one!

Vid and the others are more expert than me so maybe they can check. The EOS gap looks too small to me. Here is a pic of how mine are set. look at the difference.pasted_image (resized).png

Feel free to swap coils to confirm your suspicions too.

Good you have isolated the issue.

Just a note on cleaning the EOS (End Of Stroke) switches in this machine.

These are high current, tungsten based switch contacts and should be cleaned and dressed with a points file - just the same as an older car that uses ignition points. Using alcohol will do almost nothing to help with the cleaning of these. In fact, it could actually cause a fire due to the spark when these points operate.

Newer machines use silver or gold flashed contacts and these should NEVER be filed as that will destroy the contacts and the effectiveness of the contacts. Newer machines use the switches to tell the control PCB to switch the coils using transistors so the switches don't do the heavy lifting. These more modern types should be cleaned with a light card dampened with alcohol and drawn through the (held closed) contacts.

Hope that helps for the future.