Since I got my JP the T-rex hasn't been moving left to right. The guy I bought the pin off said it was working before transit so the fault has to be from transit. This seems believable because the occasions I have enabled the left/right action in the operator settings he has moved intermittently.

This leads me to believe that it is a dodgy connection somewhere. Sometimes, even with t-rex left/right disabled, during gameplay he'd randomly chomp his jaw once in a dozen games or so. I'm guessing that this chomping would normally be accompanied by left/right movement if it were turned on, so whenever he chomps during gameplay is when the dodgy connection happens to be working.

So today I decided to dedicate some time to try to fix the issue. When I turn left/right on in the settings he won't move in diagnostic mode at all. In both diagnostic mode and normal boot-test mode I can hear the relay switching attempting to move him. There was one occasion when he did start moving reliably and I was pleased but after moving around some of the wiring harness to do some more work he stopped working again. I am unsure if the connection issue is under the play field or somewhere along the wiring snake to the back box.

I have checked under the relay board and the shaker motor board for cracked solder and they appear to be perfect. The relay is switching as it should. When I test with a volt meter there is 35 volts passing through when switched one direction. When switched in the other direction there are no volts passing through. I believe the shaker motor uses the same relay and this is operating as it should.

Can anyone suggest where/what/how to test to diagnose the fault and find the dodgy connection? Thanks!

Bump

Even though the relay solder points all look good to my eye, would it be worth reflowing them anyway? And should I try cleaning inside the relay as well?

Yes I have always been testing in diagnostic mode because I have been leaving t-rex left/right turned off to have normal gameplay. If I leave it on then sometimes during gameplay he'll move off the center switch and be stuck there and won't pick up the ball, so I have just been centering him and turning left/right off so he'll stay there and eat the ball.

Yesterday when having time to diagnose the fault I turned left/right movement on and noticed that he was moving just fine. But after fixing a flipper issue later that day he stopped working. I'm not sure if the shaker motor action or even just the movement of the wiring harness when raising/lowering the PF is enough to break the connection, but whatever it is I can't seem to find it but I'm having trouble knowing where I should look. That's where I need your help

Where was this broken connection of yours? At the wire coil? What is that?

Just to round out this thread for anyone who is looking for a solution in the future …

The fix for me ended up being a reflow of all the solder joints in board above the shaker motor. I couldn't visually identify which was the culprit so I reflowed them all.

The board looks like this one:

de-5205065.jpg

Sorry, I solved this ages ago — I should probably update the thread title!

I just realised that I forgot to add the solution to the thread so I did this in order to be hopefully helpful to future JP owners trying to solve this problem.

Maybe it's novelty factor for me not having it work for the longest time, but I think it's great when the T-Rex moves! He moves smoothly for me, maybe if he is clunky then the gearbox needs servicing.

I actually found that with left/right turned on the animations were smoother. For example, with it turned off he'd be still for while before bending to pick up the ball. With left/right turned on he bends over immediately after hitting the center switch.

It was in the post you replied to above