Flipper sticking up - Help please...

Andydn

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Right flipper staying up after approx 1hr of play. Coil checked out fine (but gets hot when flipper is stuck up obviously).
Can you check diodes without removing them?
How do you check for a bad transistor?
Any help appreciated please.
 

Sven Normansson

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Of its playing fine for an hour then it isn't anything electronic. More likely it's binding die to heat. Check there is some end float on the flipper. When cold you should be able to pull it up and down vertically by about 1/16th of an inch.
 
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Andydn

Andydn

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What game is it on please
It’s on AFM ,
Def no need for rebuild as when it’s stuck and I power off I can move the flipper up and down without the slightest bit of resistance in the coil sleeve. It’s something electrical without a doubt.


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Sgt GrizZ

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It’s on AFM ,
Def no need for rebuild as when it’s stuck and I power off I can move the flipper up and down without the slightest bit of resistance in the coil sleeve. It’s something electrical without a doubt.


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Nope. Almost certainly a mechanical issue. Seen this before - the flipper feels fine - but replace the parts mentioned above and I bet it will sort it out.

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Andydn

Andydn

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...when it’s stuck, if I power off it drops straight away - surely wouldn’t if it’s a mechanical issue?
Also why would the coil get hot if it’s just stuck mechanically, no power going to it without flipper button pressed surely?


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biglouieuk

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Let's rebuild, we have the technology. I'll pop down and give you a hand end of the week, dying to see the machine anyway!
 
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Andydn

Andydn

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Help still needed:
Coil sleeve and end stop look virtually new.
Just played with glass off, flipper stuck on, its 100% being held electrically, as I push it down I feel the resistance, then stays down until I press flipper again and then stays up.

In test mode (for single press or hold) the flipper is down, the obviously goes up once I’m on ‘repeat’ in flipper test but it stays up - it then drops if I release the door safety switch (ie: kill the solenoid power).

Is this a diode swap now?
 

Pick Holder

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@Andydn
Change the plunger then.
9 1/2 times out of 10 its something on the flipper itself.

Is it getting caught on the EOS switch somehow. Is the switch fully intact (ie not missing a bit at the end).

Serriously do a full flipper rebuild. It doesnt matter if something looks new.
 
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Andydn

Andydn

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....and when the faults occurs and I lower the flipper, the coil is still energised but not enough to actuate the flipper up again but enough to hold it if I manually push flipper up - suggesting it’s the ‘hold’ side of things that is at fault?
 
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Andydn

Andydn

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@Andydn
Change the plunger then.
9 1/2 times out of 10 its something on the flipper itself.

Is it getting caught on the EOS switch somehow. Is the switch fully intact (ie not missing a bit at the end).

Serriously do a full flipper rebuild. It doesnt matter if something looks new.
Appreciate all your help but I can feel the coil is energised, the end is stroke switch is fine - happy to do a video.
If its stuck mechanically it wouldn’t drop as soon as I cut the power would it?
The coil doesn’t get hot until the fault occurs, prior to it happening it’s luke warm (same as left hand side)
And when I do cut the power and confirm the flipper moves freely as soon as I energise that coil again it stays up.
It’s an electrical issue, just not sure what needs changing.
 
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Andydn

Andydn

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Yes strangely, after 40 mins or so.


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Pick Holder

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Okay - if its definately energized then swap the two flipper boards over on the left and right hand side of your cabinet.

If the problem jumps - then it is an opto problem on this board.

Also clean the optos

Its very rare for a transistor fault to be intermittent.

Maybe swap the diodes as well on the coil.... they are cheap and it could be a cracked diode playing up.

Sorry - I did not read it was electrically energised.
 
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Andydn

Andydn

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Swapped the opto boards over and issue remained with right flipper.
Is there a way to test diodes and transistors without removing them?


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Andydn

Andydn

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Thank you everyone, how does this sound:

Failed diode, every time flipper is used a small amount of current remains until there’s enough residual current to hold flipper in place?
This would explain why it happens after a while and also why after turning off for a few minutes it fine again.

Feasible? (I’ve ordered diodes)


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PBrookfield

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Thank you everyone, how does this sound:

Failed diode, every time flipper is used a small amount of current remains until there’s enough residual current to hold flipper in place?
This would explain why it happens after a while and also why after turning off for a few minutes it fine again.

Feasible? (I’ve ordered diodes)
Failed diodes result in dead transistors.. The diodes are there to prevent back EMF spikes going back to the control transistor when the magnetic field collapses (i.e. is turned off.) I doubt they would be this problem, their failure won't cause a supply of power to continue flowing. But it certainly won't hurt to replace - I could be wrong.

I honestly reckon you need to replace a transistor - specifically the one for the hold winding on the right flipper. They're not easy to test in-circuit at the best of times, especially not with an intermittent fault.
 
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biglouieuk

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Failed diodes result in dead transistors.. The diodes are there to prevent back EMF spikes going back to the control transistor when the magnetic field collapses (i.e. is turned off.) I doubt they would be this problem, their failure won't cause a supply of power to continue flowing. But it certainly won't hurt to replace - I could be wrong.

I honestly reckon you need to replace a transistor - specifically the one for the hold winding on the right flipper. They're not easy to test in-circuit at the best of times, especially not with an intermittent fault.
Pop the board and test the transistors as per.in the link above? Just to be sure?
 
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Andydn

Andydn

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I want to be able to test and be sure, I really don’t want to be changing parts ‘just incase’.
Struggling to find the transistor on the board as it is, new one on the way if I need it anyway.


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Andydn

Andydn

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I want to be able to test and be sure, I really don’t want to be changing parts ‘just incase’.
Struggling to find the transistor on the board as it is, new one on the way if I need it anyway.

Easiest way to test a transistor?


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PBrookfield

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I want to be able to test and be sure, I really don’t want to be changing parts ‘just incase’.
Struggling to find the transistor on the board as it is, new one on the way if I need it anyway.


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I sympathise with that completely but you have to factor in your time's value. There are some components that are just awkward as hell to test in circuit, and some that are awkward to test at all - like crystal oscillators.

The problem is that in-circuit you can only really compare multimeter results to other transistors, and you'd need to make a judgement as to what measurements are material, and which are just normal variations. https://vetco.net/blog/test-a-transistor-with-a-multimeter/2017-05-04-12-25-37-07 You would have to take deviations from that guide in the context that you'd (I'd presume) be testing in circuit. So you'd have to compare to, ideally, the other flipper's transistor, or other transistors if you know they're electrically nearly identical to all on the flipper coils.

This is all made much worse by the fact that it's intermittent. You could do all of the above while cold, and find absolutely nothing wrong with the transistors. And you don't want to be trying to measure transistor legs in-circuit while the thing is powered on. I do some daft things but that's a trick even I wouldn't attempt - far too much chance of shorting stuff out.


The only other thing to really nail down whether it's in the flipper physical mechanism or it's going to be one of the transistors, is to physically swap the mechanisms between the flippers and seeing if the issue follows the mechanism or you still have the issue right sided.

That's an enormous bloody faff by my measure but if you're dead set on not replacing without a test, there's your test.

EDIT: Though I do have to ask - why the hesitancy to replace old-for-new if you're ordering parts in advance of knowing whether you need them...?
 
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Andydn

Andydn

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Ordered the parts as diodes are 12p and transistor was £1.35.
Don’t want to have to change them but it’s looking like they are the culprits, I was saying that I’d like to confirm it’s def these before changing them so I know 100% what the issue was. Changing parts then time testing to see if issue remains isn’t fun.


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PBrookfield

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Ordered the parts as diodes are 12p and transistor was £1.35.
Don’t want to have to change them but it’s looking like they are the culprits, I was saying that I’d like to confirm it’s def these before changing them so I know 100% what the issue was. Changing parts then time testing to see if issue remains isn’t fun.


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Fair, fair, I get that totally.

It's just that you're at the point where further testing gets invasive. Now I think about it, a more sensible suggestion for completely eliminating electronics versus physical issues, is instead of swapping the flipper assemblies - just swap the wires over. Making sure to swap the wires for the coil and the EOS switches, of course.

Have fun playing the game like that until the problem resurfaces... and if it's now the left flipper, forget about anything on the playfield, it's up in the backbox. And it's going to be one of the transistors... almost certainly.
 
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Andydn

Andydn

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I’ve swapped the optos already but honestly I’m 100% certain it’s electrical. I can physically feel it energised when I play with glass off and it happens.
I’ll change transistor and keep fingers crossed!
Obviously I’ll update on here once done


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PBrookfield

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Not the optos - the wiring to the coils and the EOS themselves. In effect you'll end up playing with your flippers permanently mirrored with respect to your buttons. It'll be a head screw.

Pro tip: cross your arms across the lockdown bar to play swap-flippers easier!
 
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Andydn

Andydn

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Not the optos - the wiring to the coils and the EOS themselves. In effect you'll end up playing with your flippers permanently mirrored with respect to your buttons. It'll be a head screw.

Pro tip: cross your arms across the lockdown bar to play swap-flippers easier!
This is to eliminate a mechanical fault though isn’t it? If so I’ve eliminated that already, just waiting on the postman now (probably a few days)!


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