Flipper "problem" when in up position

[Dolfin]

Hello all
I am new here but not new to pinball.

Most of my classic Bally machines have the "problem" shown in the video.
Here on Eight ball deluxe.

The flipper button is held in.
When the ball hit the flipper it flip a little.
The eos are new.


Is it just like that with the classic Ballys or is there a way to fix it?

Thank you

View attachment VID_20240620_152535.mp4

 

[roadshow16]

@David_Vi

 

[AlanJ]

Adjust the eos

 

[David_Vi]

What Alan says is what my first port of call would be.

Are the coil stops and plungers new? Sometimes that affects how solid the hold is.

I've found this unavoidable on some games but it's never as bad as yours is, so hopefully a EOS switch adjustment will lessen it.

 

[carl lawrence]

As above check the eos switch , next check the cabinet switch has not welded if self together ,then lastly on the sol board check J1 connector could be cold solder joints so just reflow then !

 

[DRD]

@Dolfin

This is a very common problem that I call flipper bounce.

Flipper coils have 2 circuits. A powerful "flip" and a weaker "hold". The flip uses a large momentary current that would destroy melt/ burn out the coil if present for more than a few seconds so the hold coil uses a much lower current that is safe for extended periods.

Late 70s/ Early 80s Classic Bally flipper coils are much physically smaller and use lower voltages than the later games. As a result the Bally SS coils are relatively weak in terms of both flip and hold circuits.

The flipper EOS is normally closed meaning that current initially powers the flip coil. When the flipper is energized and the plunger pulled into the coil the EOS is opened and this switches the large flip current to the small hold current.

In order to get maximum flipper power out of these naturally weak coils you want the EOS switch closed as long as possible - but there is a trade-off of flipper bounce.

The hold coil is naturally weak. If the EOS gap is too small the ball striking the flipper tip can push the bat downwards momentarily closing the EOS. This gives a brief "flip" as the more powerful coil engages for a fraction of a second. This is what your video shows

It may be virtually impossible to completely eliminate this bounce IF you want decent flipper power on a 40 yr old machine - it is all a trade off. Especially when the game gets hot so the flippers weaken anyway and the EOS gap may reduce due to thermal expansion

There are a few places to look.

1. Most obvious is that the EOS gap is too small. Widen it and see if the problem goes away. If this is the issue - - you need to set the optimum gap through trial and error that gives good flipper power (narrow gap) whilst eliminating flipper bounce (wide gap).

2. The flipper coil may be damaged/ weak. So replace if necessary

3. The high voltage cabinet button switches may be dirty/ pitted. So clean (will require abrasive paper) or replace

4. Your power circuits/ wiring looms/ bridge rectifiers/ soldered joints are weak so can't provide enough current. You'd be very unlucky if this is the case.

 

[Dolfin]

Thanks to all of you

I should ofcourse have wtitten that the flipper button contacts are new and I am aware of the theory about the flip and hold circuits of the flipper coils.

The problem in this case is not that the eos switch is getting closed when the ball hit the flipper.
What flips the ball is the hold current.

I did get a few pointers that I will look into and get back if I find a solution for this case.

Thank you

 

[Fantazia2]

Not being an expert I would have to ask what the theory of operation would be for this scenario?

Is it a case that

1. the coil hold power should be strong enough so the flipper doesnt move and can absorb all the power from the ball,

or

2. when the flipper is up in the hold position it shouldnt have enough power to stop the ball and when the ball hits the flipper it should move fractionally and the EOS switch open/close to give full flipper power again.

So either the thing that is happening here is 1. the coil hold is too weak and the power of the ball is pushing it back and then when the power is absorbed pusing the ball away, or 2. the EOS is not adjusted correctly so the flipper is moving too far before full coil power is applied causing the flip, where if it was aadjusted correctly it would move a tiny amount that would be less noticable?