Quoted from Foz:I was able to solve this problem.
Right after installation the rex wasn't catching balls, lot of rejects, bumping off the lower jaw.
So first I tried to lower the rex head, where it would touch the ramp as closely as possible.
This worked great in terms of catching the ball, the balls had an easy entry, but the rex would hit the wire guide during horizontal movement, which caused all sorts of alignment issues.
So the next step was to move the rex up vertically, so it would clear the wire guide by a fraction of a millimetre.
Now it was able to move freely horizontally, but it would no longer catch the ball properly, and if it did catch, the magnet wouldn't hold.
The trick was to move the rex even higher, just about as high as possible. That way when the jaw opened, it could open fully without hitting anything, which would otherwise have closed the jaw ever so slightly again.
Got the idea from this post
https://pinside.com/pinball/forum/topic/jurassic-park-stern-2019-owners-club-welcome-to-jurassic-park/page/103#post-5678501
Now my rex catches 100% of the clean shots. Hope this helps somebody in the future
I had the same problem with the lower jaw remaining a quarter inch too high. The jaw would just not get low enough.
I read every possible solution, but no previous suggestion would work. The Stern service bulletin didn't help as I could not raise the top bracket any higher, nor move the lower vertical bracket any lower. I had no leeway to adjust it.
My problem was the head was too wide, so it would hit the side edges of the ramp preventing it from getting lower.
I finally got the jaw to reach the ramp by heating the Dino head and pushing in the two "wide" spots at each side while it was warm and malleable.
It became slim enough to fit within the ramp edges so it could now get low enough to allow the lower jaw to reach the bottom of the ramp surface when open.
Just wanted to share yet another method if it helps anyone who has tried everything else.
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