Hi Leosac,your in luck as the manual /schematic are available on Ipdb.
Ok ,funny i am troubleshooting the same thing plus more on a Williams Expo i just got, , anyway what you need to do is follow the path from outhole switch (the bottom of the playfield via the outhole relay to the ball release coil for the ball to be shot in to play.
Quoted from Chrisbee:
There are a few switches that can make the SCR motor run on. See if the bonus unit is getting back to zero position by looking at the pf after the ball drains.
Thats what i am thinking too Chris ^^that the zero switch may be dirty or just a bit off ,the outhole relay , switch itself or score motor switch.
Ok,Leosac are you familiar with the layout of a Em pinball. Not sure how experienced you are so until we know where you stand we will take it easy on giving too much info at once.
See here for details for what & how they work>> http://www.pinrepair.com/em/index1.htm
Starting at section 1 is a basic instruction and understanding of an EM pinball machine and of the components are as a guide to help understand how they operate.
Upon startup the game resets, the ball is in the outhole sitting and waiting for the outhole relay to energize through a series of steps.
One of them is as the bonus steps down(it should light inserts on its countdown) and through a make and break at the Score motor and other zero positions it will allow a path to complete the circuit at the time that the current can flow to finish its outhole relay activation and allowing the ball release solenoid to activate to launch the ball to the shooter lane.
One of these steps is not correctly doing its final current path. From what you are describing is sounds like it could be the bonus zero switch is the one to look for on how its behaving.
Under the playfield itself is where you will look for the Bonus unit (Advance unit disc).
Scrolling to section 2d here >>
You will see a Williams Bonus unit (called the Advance unit disc in the Triple action manual pdf page 16) that should look very much like yours,and on the right side of the rotating gear is a peg that separates the leaf switches that we are looking for,watch carefully how they open and close with game off and pressing the increment coil and the decrement coil, look at the gap of the leafs at the end of travel (decrement coil) and see how the contact is operating,as it may be just a clean or adjustment to get it to work proper.
You can do this live with the game reset and closing the outhole switch (use a plastic knife to press it if you feel uncomfortable around circuits) and press the contacts closed watching it decrement down till its zero switch opens. At that point it should step up once all while activating the outhole relay/ball release solenoid.
Someone had some closeup photos of this switching in operation.
Lets start with that first to see where you stand.
Post edited by Pin-it: Clarification called advance unit disc