I dont know much about Data East but I'm trying to learn. Right now I have an Playfield Status error that shows theses errors:
T-Rex up #57
T-Rex Left #32
Left Slingshot #43

I'm thinking that if this was a Williams/Bally pin, then I would check the transistors to see if they were bad.

I'm pretty sure that is not a switch metric problem and the wiring and diode on the switches look good.

Is there a drawing or schematic that show what and where to find these transistors? Is there anything else that I am overlooking?

The motor moves at times left and right. There was a time that it would not move left to right and it keep trying to spin the motor to the left. After a time of letting it set for a bit, it started moving left and right again. Switches open and close as they should and the up and down motion works fine also. Well, it don't seem to want to go all the way down as if it was picking up the ball.
Is there any maintenance tips or suggestions that would help with the performance of the T-Rex?

Motor is back to wanting to move in just one direction now. Triggering the left or right switch does not influence the direction of the spinning.

Yes it has DC voltage and the motor spins. It just spinning in one direction, motor does not reverse direction back and forth with press of left and right flipper buttons

Where is the motor relay?

Tip122 tested good compared to the others and I was able to ground the coil for it to fire.
As for the motor, it just spinning in one direction, motor does not reverse direction back and forth with press of left and right flipper buttons.

I found a loose green/blue wire a few days ago and I soldered to the white/orange wires of the slingshot. Not sure where is goes for sure, but the other side had a green wire on it also.
So as a test, I un-soldered the wire thinking that might have been the problem. Now the slingshot error does not show up on the playfield status, but the slingshot still does not work.

20210718_183917 (resized).jpg

Moving the connector for the relay made the left and right controls work again. I did not see any cold solder joints, but I heated them up anyways.

Found this info here,
https://pinside.com/pinball/forum/topic/jurassic-park-club/page/165#post-5869143

Still getting the T-Rex up error #57
I thought that the switch might be bad, but the the T-Rex menu I can see that the switch opens or closes.

T-Rex seems to work even thought it shows a error in the playfield status menu.

Still don't have a working slingshot. Q10 test good on the DMM and I can still ground the coil and make it fire.

Thoughts?

Well, It didn't at first until I started thinking about the placement of the green/blue wire. I ended up moving that wire to a difference lug and the switch started registering.

I still got the T-Rex Up #57 error in the Playfield Status test, but when I do the T-Rex test the up switch turns off and on as the head raises and lowers.