There are two idc connectors (one on each side) of the ball trough that have a tendency to loosen. That can cause the game to think that the balls have drained. So it does the end of ball sequence (dead flippers) and kicks u out a new ball.

You have to just push them back on snug every once in a while. I do it every time i have the playfield up.

Or you could simply replace these connectors with Molex connectors and trifurcon pins.

I've had 3 newer Sterns with this issue. I've replaced the connectors as mentioned above and have never had the problem return on those machines.

Would putting a couple of wraps of electrical tape on them work too?

It has nothing to do with holding the connector on. It has to do with the "electrical" connection between the IDC connector and the header pins on the opto board. The trifurcon crimp on connectors grab the opto board header pins better and the CPU doesn't see a loss/drop of the electrical current. This loss/drop is what signals to the CPU to end the ball.

I see, thanks.

Tktlyr, do you have a parts list and links on where to get them?

https://www.greatplainselectronics.com/products.asp?cat=80

https://www.greatplainselectronics.com/products.asp?cat=86

Don't forget a crimper!

There's a thread on the forum discussing ratcheting crimpers. Search it out and spend the extra $10. From someone who has replaced a bunch of connectors, a good ratcheting crimper is worth the investment.

So i have little exp with this, so bear with the dumb questions...

Basically you are saying to.

1 remove the idc connector.
2 strip a bit of the insulation off wires running to trough on each side
3 crimp on the clips to each wire
4 put the clips/wires into new molex
5 slide the molex onto the existing pins on trough

So no modification is needed to the trough side?

And these dont vibrate off? Even with a shaker?

Your procedure is correct.
No modifications to the trough.
They don't vibrate off. Even with a shaker.