(Topic ID: 134714)

Jurassic Park T-Rex Left/Right motor wiring

By ddebuss

7 years ago

Topic Stats

  • 8 posts
  • 4 Pinsiders participating
  • Latest reply 7 years ago by Crash
  • Topic is favorited by 1 Pinsider


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#1 7 years ago

Been restoring a Data East Jurassic Park for some time now. Still fighting with T-REX. I had a bad switch on the T-REX down switch and during the replacement both of the wires to the left right motor came loose. Soldered them back on and she hasn't been the same. I think it's wired backwards since it now is going nuts when T-rex is enabled including resets. Thought i had pictures from the restore but i can't find them. Can someone take a look and let me know if it's right or wrong. Thanks for the help! Dan

#2 7 years ago

That's the left/right motor.

#3 7 years ago

Thank you. Corrected the title. It's the left/right motor that was rewired.

#4 7 years ago

Here's a post that may help if you're still having left/right problems.

IMO, the game has a design flaw. The factory board only provides a half-rectified signal to the left/right motor--causing it to move very slowly -- sometimes too slow, so the CPU thinks there's a problem and flags the motor as non-responsive.

On a friends game, I modified the circuit board so that the l/r motor gets a full rectified signal (vs factory half-wave rectification). He is very happy with the operation of the t-rex now, and the t-rex has been working flawless since we fixed it.


#5 7 years ago

Thanks for the great work and the great tip. I'll probably include that as an uparade to the game as a next step.

Having said that I'm still not sure it's wired right. The game and t-rex was working good except it was not eating the ball reliably. Found the switch is bad. Replaced the switch. Found these wires to the motor had come undone. Reattached them. Trex is now a mess causing resets. I believe they are backwards and would love someone to do a visual on theirs so I can eliminate that as the cause.


#6 7 years ago

Hi Dan,

Here are your requested photos of the JP Left/Right motor. I hope this helps you out.



#7 7 years ago

Hmm. Appears to wired the same as mine...

#8 7 years ago

Check the directional relay mounted underneath the playfield. If it is shorted or otherwise malfunctioning it can cause issues.

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