Well, Caveman just started to do this yesterday:

When the pin is turned on, all the coils fire immediately & I think some stay locked on.

I looked inside the coin door and I can see the free game knocker fire and stay locked until I power off. I see the pop bumpers all fire once and all the insert lights come on and stay on. I dare not let it stay on for more than 2-3 seconds so I power pin off immediately to avoid frying coils or transistors.

I am not very familiar with Gottlieb issues like I am with Bally/Williams, so any suggestions what to check first would be greatly appreciated.

Thanks!

Thanks for the reply. I did ground the connector between the MPU board and the DRIVER board some time ago from TNT's youtube video but that's the only "extra" grounding work I have done. Do you really think that my issue is because of the GND issue? This is a really clean game so doubt it's acid or corrosion.
I have already pulled, wiped connectors w/ soft cloth and reseated all the connectors in the backbox. Funny thing is it did this lock up thing Saturday AM, came back later in afternoon and it started fine. Played a great game. Powered off pin. Went to turn it back on Sunday and back to that coil fire lockup sound as soon as I flip the power. It's definitely not forgiving this time.

So I am thinking about buying a Rottendog MPU080 MPU board. Not sure what I need to fix this lock on THUNK issue but the replay knocker fires and stays on. The GI flashes briefly, then all the insert lights come on and stay on.
I'm no Gottlieb expert and from what I read they can be a real headache to work on so was hoping that the Rottendog may be the way to go?

Update: Ok, this Caveman is possessed. Turn on this morning, all is fine now. Go figure. The F11 fuse was blown so replaced with 2A SLOBLO.
I did go thru the bottom cabinet yesterday, tightened up all the grounds and I do have the newer pair of capacitors in there someone replaced before I got pin.

Anyhow, another question for someone with a schematic.

My 5X insert light only works if I pull the top edge of Connector A3-J3 out just a smidge. Push the connector back on firmly, the 5X insert light will not work.
Which pin on that connector do I need to inspect, clean or change that controls the 5X light?

THANKS!
CuJo

That is a good catch. It is labeled wrong in the manual, isn't it?
What does the little "544" mean? So it's pin 5 on the connector?
Thanks so much!

Thanks Peter!