Hello everyone,

there is an intermittent problem where on Sing Along at the start of a game, the ball count unit will pulse twice so the game starts on ball 2 rather than ball 1
The game is going to game over correctly.
The ball count unit step up coil is activated by the trough switch which the ball is only rolling over once.
The ball count unit appears to be stepping up and down correctly and the wiper plate looks to be in the correct position relative to the rivets.
Strangely, sometimes the game works correctly and starts on ball 1.

Any help appreciated, many thanks.

Thanks for your reply Howard,

the switch looks ok, when I manually activate it, it steps the ball count unit up one increment.
From the schematic, there are no other switches involved in that circuit but I shall have another look at it.

Many thanks, Richard

Hello Tim, thanks for your reply,

the ball count unit seems to be operating correctly, it steps up positively and consistantly and steps down quickly and consistantly, the return spring tension is ok, it always goes to the stop and the ball in play wiper always goes to the minus 1 position on the rivets at reset, which I believe is correct.

I have watched closely what happens when the game resets and, when starting a new game, the ball in play lights go from game over, (5th rivet on bcu) to no lights lit,(minus 1 rivet) to ball 1,(1st rivet) the ball eject solenoid then kicks the ball over the trough switch and the ball in play light goes to 2, so I am (fairly) sure that the bcu step up solenoid is being pulsed twice.
What is baffling me the most is that occasionally it will work correctly, suggesting that the bcu is working correctly but some how getting an extra pulse to it's step up solenoid, the trough switch is only closing once and the ball in play light goes to 1 before the ball is kicked out.

Thanks for your help, Richard

Thanks pinengineer, I shall check that.

Regards, Richard

Hello Howard, that's a good idea, unfortunately the game is about an hours drive away.

The ball count unit looks to be working correctly, I may be wrong, but I can't see anything wrong with it, when it resets it goes to the minus 1 position on the ball in play wiper/rivet which seems correct, as when it (occasionally) works correctly, that means that when the ball goes over the trough switch it steps up to the ball 1 position. What happens 90% plus of the time is that the ball count unit steps twice, once before the ball is ejected and once when the ball is ejected and rolls over the trough switch.
It's got me baffled! I shall have a closer look at it when I can.

Many thanks, Richard

Hello Tim,

thanks for that, I shall investigate further.

While I was lying awake at night thinking about it, I had a thought, there are two key things,

1. the fault does not occur 100% of the time.
2. the fault only ever occurs at the start of a game, it never skips from ball 2 to ball 4 or 3 to 5.

This got me thinking about what happens at the start of a game and it occurred to me that when the relay banks reset, the action is quite violent and I'm wondering if there is enough vibration to close the trough switch, because the ball in play light goes to ball 1 during reset (so the bcu is stepping up then) and then to ball 2 when the ball rolls over the trough switch. If so, it would just need a bigger switch gap.

Looking at the schematic, the bcu step up solenoid is controlled by the trough switch and nothing else so I think that is where the problem lies.

I wouldn't have thought of your explanation so many thanks Tim, when I can I shall have a look at it ( the game is not with me)

Thanks again, Richard

Thanks Tim,

I'm going to have a look at it this weekend.

Richard

Success!

I looked at the game today and have resolved the problem, with someone else pressing the start button I could immediately see that the ball count unit was not resetting to the zero position as I had thought, but was resetting to the ball 1 position.
When I activated the reset solenoid by hand, it reset 100% of the time but obviously the pulse the reset coil is getting is not as strong as my finger.
I increased the tension of the torsion spring by one turn and the problem happened less frequently so I increased the tension by another turn and it now resets correctly and goes to ball 1 when the ball is kicked over the trough switch.

Many thanks for your suggestions, they steered me in the right direction and are much appreciated.

Thanks again, Richard