Check the spring under the playfield that forces the post back down after the coil shuts off

Just disable it, Ive never played a TRON that has it enabled.

It is a complete waste of a mech.

Lol! Wtf? I despise those pop up posts. An unneeded hole in the PF.

If they are skilled enough o hit Gem off the plunge they should be skilled enough to hit it with the upper left flipper or a bounce off the Tron targets. Just saying

I find the only real advantage to the up post is if you are trying to get light cycle 2 and having a hard time hitting the shot through the pops. Off a plunge it will award that shot if you let the ball get stopped by the post.

But, to fix the problem. You most likely have something interfering with the coil as even with a bad spring I would think it would still go down with the weight of the post and the shaking of the machine. Have you checked to make sure the coil isn't locking on?

Years later I am still surprised the first game on a location Tron and I plunge around and that pops up. My brain just screams that I'm at a location and why are you not holding the left flipper!!!

I agree, the post is a complete waste.

Had a similer issue with a Champion Pub. Turn out to be a number of problems. The mech was out of allignment and rubbing in the hole The spring was collapsed and needed to be replaced. And the post was magnetized somehow.

I found something similar on my Tron. When you have the playfield raised, move the plunger up and down to feel the friction. As you gently bend the bracket up and down, you will feel the rubber rubbing against the playfield at extreme bends. Through a bit of trial and error, I determined that I needed to bend the bracket slightly downward. I suppose you can also take out the bracket and put a really good right angle on it.

It wouldn't hurt to clean it while you have the parts apart, but it seems the rubber rubbing due to misalignment is a far bigger impact on sticking.

I couldn't figure out how to replace the rubber, but I imagine something less tacky such as Super Posts might help.

Then you sir, have found the proper order and combination of curse words to fix a problem. Hope you wrote it down

Take the mech apart and clean it. POTC ship post and WOF scoop exit post also do this frequently. Also as someone else mentioned, the plunger shaft can become magnetized.