Jurassic Park TRex Issue

gsrogers

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I just picked up a Jurassic Park that has a TRex issue. It will not go left and right on it's own. I installed a new motor and gear assembly but no go...it seems to not have enough power to move on it's own. Is there a driver transister or something that controls the left and right motion power? Thanks in advance
 
Yes, the option is turned on...it will work but jerks along. and seems to go one direction with both flippers during the test. Once it goes all the way to the right it will not go left. I pulled the motor and set it to the center and the motor will work in both directions but is does not seem to have much power and kinda jerks along. thoughts?
 
If you pull the motor and try to move the T-Rex, does it move smoothly? I'm asking to find out the condition of the gear box. With the motor out of mine, I can move the T-Rex back and forth fairly easily.

Also, check your serial number and ROM version and look here:
http://www.sternpinball.com/ServiceBulletins.shtml#93
There were service bulletins regarding the T-Rex right-left movement. Your machine is probably fine, but it never hurts to double check.
 
Yes, if I pull the motor is moves smoothly...actually the gearbox and motor are new. The problem seems to be with what controls it...what board controls the Trex?
 
Looking at the schematics, there is a bi-directional relay (520-5066-00) that controls the T-Rex and shaker motor underneath the playfield. It is probably not the problem if you are not noticing problems with anything else. There is a brown-violet wire that comes into the relay from CN12 on the CPU board as well as a red +32v wire from PS connector CN3, pin 6&7. The brown-violet wires goes back to CN12 on the CPU. I believe it is pin 5 on the CPU that leads to solenoid driver 12. Don't know if this will help, but hopefully it will get you in the ballpark and let you start checking out transistors.

Edit: And hopefully I'm reading the schematics correctly. It is getting late. :)
 
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I appreciate the help...I will check things out more tomorrow. The shaker motor is working correctly. The Trex also works great up and down just not side to side. Garry
 
i checked the connectors and I am getting 41 volts from the power board CN3. I can hear the motor trying to turn when in test mode but it just acts like there is not enough power. If you have had this problem before, Please chime in.... Thanks
 
i checked the connectors and I am getting 41 volts from the power board CN3. I can hear the motor trying to turn when in test mode but it just acts like there is not enough power. If you have had this problem before, Please chime in.... Thanks

PM me your email address and I'll send you a scan of the portion of the schematics.

The schematics show 32 VAC from CN3 on the PS and 28 VAC into the relay under the playfield. The motor is 9 VDC, but I don't think there is any rectification anywhere. It doesn't sound like you have a problem with the voltage from the PS?
 
i did some work on a jp that had the same left/right symptoms

all i did was wait for his head to get stuck in one direction (it wouldnt/couldnt go right) and gently! help it back to center, not sure why this had any effect but it worked fine after that
 
I wish mine was that easy....I have narrowed down one problem to the relay on the bottom of the playfield. It would not switch back and forth so the Trex would go one way if you pushed either flipper in the test mode. When it hit the end switch it got stuck. Same thing was happening in game mode. I will change out that relay. Any tips on where to find the correct replacement would be appreciated. It is a 24v 2 lead relay that has legs that will mount on the small pcb.
 
i turned off my left/right movement. i had heard some horror stories on that particular motor....probably doesn't make much of a difference, but i don't care about the left/right anyway.


good luck with your problem....there are a lot of posters familiar with JP around here. i'm sure somebody will be able to help you out.

geese is a JP guru. ;)
 
When I got my JP it had an extra wire running from the 12v regulated power on the power board directly to the TREX. I disconnected it at one point and it caused the TREX to barely move back and forth. I reconnected it and now it works great.

Also, make SURE you get the newest romset for your JP. In the final version of the roms they changed the control for the TREX. I believe they pulsed the signal rather than giving it a constant signal? Either way it is supposed to drastically increase the life of both TREX motors.
 
Hmmmm, I will check the ROM...maybe that is why I think it "pulses". Thanks for all the help guys.
 
I fixed the issue....it was the relay under the playfield. I would not switch back and forth causing the trex to get stuck on one side.
 
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