Success! Must have been a timing thing:

1. Reach under and switch on the machine
2. Within ~1 sec, press and hold the trigger.
3. Free Play is illuminated
4. Play

Easy peasy. One of the documents I read did describe the OPPOSITE scenario (press trigger to enable diagnostics). Happy to avoid those diagnostics each time.

Thanks Chad/Dan!

Because we were still trying to design for the operator that has one of these on location and installs the code. We didn't want to make anything that had to do with coils or functionality change for them. If an arcade or location fires up the games by throwing a breaker panel (like many do), the game tests itself as normal and continues the exact same functionality as before. If you are playing by yourself, you pull the trigger if you want to skip it. It's much rarer in a home setting to be starting the game by using your circuit breaker, and if you are, it's likely that you aren't really affected by the T-Rex diagnostics anyway. If you're standing right there, it shouldn't be hard for you to pull the trigger.

We did a number of little things like that for ops in the code. I used to manage an arcade so it's where my mind always goes to first. For instance, I think it was on TFTC, we changed the high score table values to be a little higher because it seemed like the new code bumped up the score a bit, and I was winning too many free games on it. Bumped them up so if you install at your location, you're not giving away a ton of free games.

We really tried to look at this from all angles

Just wanna say a huge THANK YOU to Chad and everyone involved in this code and topic.
...I finally have the new code in my Jurassic Park and play it all day and I tell you it's so much better now! Even more than I thought it would.

The fact that you now must own your Tri-ball alone adds so much to the game. First I thought it would be a rare to see Tri-ball at all with the new code. Well I was wrong, I often get the Tri-ball before the 3rd Ball. There are so many ways the get the Dino targets complete and the feeling then a Tri-ball is lit is so good now. Even little stuff like actually see how much points you get from a random raptor adds so much and just needed to be in the game. The list goes on and on...so thanks again. The game is so much better now. I'm glad I keeped my Jurassic Park this long.

just wanna say,
mr. chadh you are brilliant!!!
thanks a lot for this great awesome code!!!!!
made a great pin even greater
you da man!!!