Nine Ball premature end to multiball.

[onetaste]

Hi All. I have a Nine Ball with an Altek replacement MPU board (the original had bad battery acid corrosion). When multi ball is started, 50% of the time it comes to a premature end, i.e. while the balls are still in play the game behaves as if all 3 balls have drained, the ball has ended and starts counting down bonus. On a long multi ball it does this 100% of the time. It never does this in one ball play so this leads me to think it is a logic problem, not a ball trough problem.
Does anyone have experience with this problem or have any suggestions? I love this game, it is one of my favourites of all time, so I would like to get it going nicely. It is the goto game for most players here in the tournaments I run, so fixing this is important.

The micro switches in the ball trough test OK (although I haven't put them on a long test.) It doesn't appear that there are any replacement switches out there?

Thanks in advance, Greg

[Ballywannabe]

For starters, I am impressed you can have a long mulitball on Nineball!!

Mine will do the same occasionally, and from what I can make out it is the balls not rolling down the outlane trough and getting 'stuck' on the top switch.  If ANY of the trough switches (on-field chute on the left and outlane trough) are not behaving the game can get confused.  The Altech will have the latest ROM code, which seems to work well as long as the switches are working correctly and it can keep track of where the balls are.  I remember 'back in the day' with earlier code revisions the game had a mind of its own, and if you were lucky it would just keep spitting balls out

Try taking the apron cover off and putting balls in at different speeds and angles and seeing if they get hung up on the switches.

cheers
Ian

[onetaste]

Awesome, Ian, Thanks. Will do. I love this game, it is very nicely balanced, there are a bunch of different things to go for that are all lucrative. Unlike many DMDs the optimal strategy regularly changes as the ball progresses. I have had this game in my collection 2 years and it is still heavily played by me and others. 

Here is another suggestion which came from Pinside
"With the number of balls flying around and the number of switches being hit simultaneously I would suspect a shorted diode somewhere causing a phantom switch closure on the outhole.
I don't have schematics handy to suggest which diodes to check, you may just have to systematically test them all."

Cheers, Greg

[Ballywannabe]

Yeah, it is a great game, but can be frustrating at times!

I don't think it is multiple switch closures/faulty diodes on mine, as it only happens very occasionally and always on the second ball draining, leaving me playing a ball with the bonus counting down