Quoted from sataneatscheese:
I want to join the Jurassic Park club and am looking to trade a WCS I fixed up really nicely. The WCS was my first pin, and there were a few extra things I had to fix I wasn't expecting to have to fix due to a lack of knowledge on my part. What should I be looking at in a Jurassic Park machine other than the usual, everything works, playfield not scratched up, basic condition, etc. Is there anything specific I should look out for? I'm guessing the TREX being fully functional is at the top of the list. I have had 3 offers in the few hours I've had it up, but have seen no pictures. One is advertised as "players condition", another is missing the TREX and main ramp, and another is fully functional but "the ball won't go down the TREX shoot". Just how hard is it to get the TREX working? Is this a maintenance heavy machine?
Thanks and having a lot of fun reading through 4,651 posts on a single pinball machine. Ain't the internet grand?
Definitely get one that HAS a t-rex. If it's missing, you're going to be in rough shape trying to find a replacement. The mechanism isn't too terribly complex, but there is a gearbox as part of the left/right turning movement that can wear down. I'm not aware of an aftermarket repair for that other than finding a replacement motor/gearbox. I'm not sure how readily available those are at this point.
There's literally just a hole down the middle of the t-rex for the ball to fall into the subway below. If the ball isn't making it down into the subway, there's blockage - perhaps a screw that's too long holding the plastic t-rex parts on. The screws thread right into the ball's path in the t-rex frame. You're potentially looking at an overlong screw in the back of the t-rex's neck or the 2 screws in the front of the t-rex. I can't think of anything else besides potentially debris in the path.
Basically for the t-rex to function, you've got to have left/right movement working (some people disable it if gears are worn down), left/right t-rex switches working, center t-rex switch working, t-rex trough switch working, t-rex up and down switches working, t-rex up/down movement/motor working, t-rex jaw link mechanically working properly, and coil that drives the jaw working. These can all be basically tested in the t-rex test menu.
I'm not sure what you should expect for trades for your WCS. It might be worth checking average values of each and make your decision from there. Maybe you can expect a similar condition JP, or perhaps get cash your way for one that's not fully working. It sounds like some people might be interested based on your offers. I wouldn't trade a JP for one, but JP is a grail theme for me.
As far as maintenance goes, I haven't found the t-rex to require much. I replaced the jaw frame and link assembly to remove slop in the old ones, but I haven't had to do too much to it over the years. Otherwise you're looking at similar maintenance to any other game from the era. Things go wrong here and there and you fix them as you go.