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Jurassic Park (1990's version) not starting - Any ideas?

As an aside, I nearly have Sea Scare fully working. The circuit diagram, when compared with Jurassic Park, shows how the electronics has changed from 1977! Quite simple. The only integrated circuit is for sound. I do hope the coils have some life in them as I doubt I will be able to get replacements. (Actually, I will lookup if Recel of Madrid still exists!)

There was a sticky digit counter and contacts had corroded. There are no playfield lights at all but I tracked that down to a 9A fuse. Actually the fuseholder is knackered. Similar problems I encountered with JP made 18 years later! You'd think they would have improved in that time.
 
ger_marsh said:
As an aside, I nearly have Sea Scare fully working. The circuit diagram, when compared with Jurassic Park, shows how the electronics has changed from 1977! Quite simple. The only integrated circuit is for sound. I do hope the coils have some life in them as I doubt I will be able to get replacements. (Actually, I will lookup if Recel of Madrid still exists!)

There was a sticky digit counter and contacts had corroded. There are no playfield lights at all but I tracked that down to a 9A fuse. Actually the fuseholder is knackered. Similar problems I encountered with JP made 18 years later! You'd think they would have improved in that time.
Click to expand...
Those Data East fuse holders are absolute garbage. Replace all of them on your JP if you can.
 
I am awaiting the repaired playfield power board and noticed that one of the flippers rests at the incorrect angle. (I assume it is supposed to be parallel with the low metal bar behind it as it is on the other flipper.) I sussed out that the flipper is secured using an Allen bolt but I wonder if there is something special about them as I have attempted to undo it with a sizeable Allen key but am concerned I may fracture something else. Is there a nack to loosening the flippers?
 
You don't happen to also have a dray horse around, do you? Just hitch it to the end of a large allen key and you might be able to get those flippers loose ;)
 
They can be tight and let go with a crack sometimes, they’re standard thread but make sure you’re undoing them the right way if they’re facing away from you, ie not tightening them. I use a mini rachet drive with the correct (very snug fit)Allen bit in as it gives you more options with positioning.
 
Jagspete said:
They can be tight and let go with a crack sometimes, they’re standard thread but make sure you’re undoing them the right way if they’re facing away from you, ie not tightening them. I use a mini rachet drive with the correct (very snug fit)Allen bit in as it gives you more options with positioning.
Click to expand...
Thank you. I may try to remove the coils for better access.
 
I'm relatively new to owning pinball (mid last year) and at first I thought I was going to break something when loosening flippers to realign them.
They're unbelievably tight!
 
Thanks to everyone - and especially Pinball Heaven - for all your help. The machine is now playing as it should and looking quite good even if I say so myself! The T-Rex head does seem a bit arthritic sometimes as he does not quite manage to eat the ball so I may have a look at that.

I think there is a bit of a design flaw with the rollovers at the top of the loop. Sometimes the ball is travelling slowly with insufficient momentum to depress the switch so gets stuck. It takes some shaking to release it.

I find the game difficult to get big scores but still learning. I did manage to loosen the Allen bolt holding the flipper paddle and that is now much better, thank you. Took some effort to undo though!

Even Sea Scare is now fully working too. However, JP is much more exciting game to play.

After this experience and once the owner has the machine back, I am tempted to get another thanks to the support of the people here.
 
Wow, well done my projects usually take at least a year, other machines come and go in that time though!
 
Jagspete said:
Wow, well done my projects usually take at least a year, other machines come and go in that time though!
Click to expand...
It would have been quicker apart from lambing and other activities getting in the way! I took advantage of some really bad weather to do the indoor jobs.

I forgot to mention another little on-going problem though. The left slingshot has the rubber band cable tied to a small bar. I notice that the ball can get stuck there too. No problem on the other side. Next time I have the glass off, I will measure the width of both channels.

Oh, and some git has scratched the glass in a few places.
 
I have a DE JP and my T Rex was dropping the ball recently.
If she (afterall all the animals in JP are female😂) drops it while returning to the upright position its the solenoid that closes the mouth losing power momentarily.

Please forgive my terminology as I only learnt about these things since owning pinball but the wire gets put under a lot of pressure when Rexy turns, after many years one of the wires in the sleeve becomes weak, (like back in the day when one of your earphones used to stop working and you had to fiddle with the lead).
So the wire is broken but still making contact until Rexy moves up or down, when it breaks the solenoid loses power for a second, enough for the mouth to open.
Pictures make it easier to understand!

20210502_182518.jpg20210406_124843.jpg20210406_124530.jpg

What I did (which is a temporary fix) is find the point of failure and just try to solder the wire back and wrap it in tape.
Long term that entire grey wire needs replacing.


For your sling shot rubber issue...
Most rubber kits (and even the manual) have these rubbers listed one size too big at 2 3/4, this means they're slightly loose and end up blocking the inlane, especially the left in lane.
I had this problem also and found that they require a 2 1/2" rubber.

The previous owner probably tied the rubber to that metal guide to try stop the rubber sticking out and stopping the ball.

The rollover switches issue, mine are fine so I think yours probably just need replacing or adjusting.
I did have one dodgy rollover in the control room, meaning sometimes a mode would start and sometimes it wouldn't because the ball wasn't pressing the rollover correctly.
I tried bending the rollover switch to ensure the ball depressed it at whatever speed the ball was traveling but eventually just replaced the switch and it worked every time.
I later discovered the switch it's self was dodgy, with the wire contacts being bent so much to attach the wires it had broken something inside (hard to explain for me!) but definitely look at adjusting the metal part and doing switch tests and if they're still working intermittently, just replace the problem switches! Cheap as chips!

Hope this helps!

DEJP is quite a brutal game, the slingshots are bigger than on other pins so you get a lot of outlane drains from the ball flying from left to right.

I only rerubbered mine with Perfect Play rubbers yesterday and made a few adjustments, seems to be playing a tiny bit easier now 😂

Any questions I'm happy to answer!
I am new to pinball, JP is one of four pins that I've only owned since mid last year and have had to learn as I go, so probably discovered similar issues to you 😁
 
David_Vi said:
I have a DE JP and my T Rex was dropping the ball recently.
If she (afterall all the animals in JP are female😂) drops it while returning to the upright position its the solenoid that closes the mouth losing power momentarily.

Please forgive my terminology as I only learnt about these things since owning pinball but the wire gets put under a lot of pressure when Rexy turns, after many years one of the wires in the sleeve becomes weak, (like back in the day when one of your earphones used to stop working and you had to fiddle with the lead).
So the wire is broken but still making contact until Rexy moves up or down, when it breaks the solenoid loses power for a second, enough for the mouth to open.
Pictures make it easier to understand!

View attachment 138080View attachment 138081View attachment 138082

What I did (which is a temporary fix) is find the point of failure and just try to solder the wire back and wrap it in tape.
Long term that entire grey wire needs replacing.


For your sling shot rubber issue...
Most rubber kits (and even the manual) have these rubbers listed one size too big at 2 3/4, this means they're slightly loose and end up blocking the inlane, especially the left in lane.
I had this problem also and found that they require a 2 1/2" rubber.

The previous owner probably tied the rubber to that metal guide to try stop the rubber sticking out and stopping the ball.

The rollover switches issue, mine are fine so I think yours probably just need replacing or adjusting.
I did have one dodgy rollover in the control room, meaning sometimes a mode would start and sometimes it wouldn't because the ball wasn't pressing the rollover correctly.
I tried bending the rollover switch to ensure the ball depressed it at whatever speed the ball was traveling but eventually just replaced the switch and it worked every time.
I later discovered the switch it's self was dodgy, with the wire contacts being bent so much to attach the wires it had broken something inside (hard to explain for me!) but definitely look at adjusting the metal part and doing switch tests and if they're still working intermittently, just replace the problem switches! Cheap as chips!

Hope this helps!

DEJP is quite a brutal game, the slingshots are bigger than on other pins so you get a lot of outlane drains from the ball flying from left to right.

I only rerubbered mine with Perfect Play rubbers yesterday and made a few adjustments, seems to be playing a tiny bit easier now 😂

Any questions I'm happy to answer!
I am new to pinball, JP is one of four pins that I've only owned since mid last year and have had to learn as I go, so probably discovered similar issues to you 😁
Click to expand...
How did you detach the head to see the wires?

Also, could you please send a close-up of the front area of T-Rex? I am surprised to see just a plate of metal there and some strange higher platform which the ball can enter. If the ball flies up there fast, it is not going to do that head much good.
 
ger_marsh said:
How did you detach the head to see the wires?

Also, could you please send a close-up of the front area of T-Rex? I am surprised to see just a plate of metal there and some strange higher platform which the ball can enter. If the ball flies up there fast, it is not going to do that head much good.
Click to expand...

If you enter the T Rex test menu in diagnostics you can make him go down as if he's eating the ball by pressing the start button, (make sure he's centered first) that gives you access to three screws that remove the semi circle piece of plastic that goes around the back of him. Once that's removed you have access to that wire which is attached using zip ties.

The ball often flies up that piece of metal, i believe that's by design and isn't an issue. I haven't heard of any damage to the T Rex, (at least in the pinside owners thread).

I'll find or take some better pics later
 
David_Vi said:
If you enter the T Rex test menu in diagnostics you can make him go down as if he's eating the ball by pressing the start button, (make sure he's centered first) that gives you access to three screws that remove the semi circle piece of plastic that goes around the back of him. Once that's removed you have access to that wire which is attached using zip ties.

The ball often flies up that piece of metal, i believe that's by design and isn't an issue. I haven't heard of any damage to the T Rex, (at least in the pinside owners thread).

I'll find or take some better pics later
Click to expand...
I discovered that it is not the solenoid working the jaw which is the problem. It is just that the head does not go down far enough. I shall try to work out what is going on there.
 
Well it was/is a cable problem! If the head has not accurately aligned with the centre switch, it does not descend low enough as the tension in the cable prevents it. Only a couple of mm's out and it does not grab the ball. I may remove the last cable clip and see what happens. I don't think the cable will snag on anything.
 
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