Flipper sticking up - Help please...

PBrookfield

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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)!
Yep - purely to eliminate absolutely bizarre Zebra-factor cases.

Which it won't be. It'll be the transistors
 
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Durzel

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Confused at the advice..

If the coil is getting hot then it’s obviously staying energised, which rules out a mechanical problem. A stuck flipper would presumably be on low power anyway if just mechanically stuck anyway, and should not get hot no matter how long it’s held like that (otherwise cradling would be dangerous)

It is certainly feasible that electrical problems manifest when components elsewhere in the machine have warmed up.
 
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PBrookfield

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If the coil is getting hot then it’s obviously staying energised, which rules out a mechanical problem. A stuck flipper would presumably be on low power anyway if just mechanically stuck anyway, and should not get hot no matter how long it’s held like that (otherwise cradling would be dangerous)

It is certainly feasible that electrical problems manifest when components elsewhere in the machine have warmed up.
A marginal end-of-stroke switch could be not-fully-closed and periodically opening up, triggering the power coil to come back on (as per design - well, at least until the game starts noticing that it's broken and starts ignoring it)
Said EOS switch could also be binding up.
And a partially-not-fully-failed diode could be doing strange things to the transistor by not fully cutting out back EMF. (Yes this is electrical and not mechanical, but the diode lives on the flipper coil and would be grouped with 'mechanical problems' as part of the wire-swap test)

Like I said before - it's zebra-hunting in the extreme but as it stands this would be a quite an unusual failure case for a transistor anyway - one where if the transistor gets warmed-up enough, it becomes de-rated enough to start displaying avalanche breakdown behaviour at way, way lower energy than it should.

It's a little easier to have this behaviour on pre-Fliptronic systems where the EOS is normally-closed instead, and not having it open would keep the power winding on. There would still need to be some sort of failure up-stream to make the game keep the power flowing, though.

I'm used to seeing very weird problems sometimes - the latest one absolute nonsense problem with an absolute nonsense solution I've seen, is this impossible-to-diagnose bad boy: https://forums.arcade-museum.com/sh...zxTe2FYWNdqUPoeKSMJZTysBZIbxHimCAwI7qSNO0kJmM
Wasted hours upon hours with this one, only to find the solution online and I can say that even if I put another ten hours into the thing, I would never find it.

As to why I was even suggesting such mad things - well, I'd said transistor-at-fault first, and I heard that peace-of-mind by positively identifying the fault before replacing anything was the ideal.
Because I'm me, I took that challenge to my usual extremes.
 
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AlanJ

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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.
I agree with the above, get some extra wire and hook it up so you swap the flippers over electronically - ive done this twice and helped tell me where the fault is. I had a very weird one on my LOTR which turned out to be a dodgy transistor that became unreliable when it heated up, from cold it worked perfectly. Swapped the transistor and problem was solved.
 
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myPinballs

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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?


Sent from my iPhone using Tapatalk
Test the flipper coils in test mode (remember 2 drivers per coil, power and hold), then test the flipper optos in the switch test. Look specifically for optos going on and off very fast. My guess - optos failing/breaking down after being on for a period of time
 
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Andydn

Andydn

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Test the flipper coils in test mode (remember 2 drivers per coil, power and hold), then test the flipper optos in the switch test. Look specifically for optos going on and off very fast. My guess - optos failing/breaking down after being on for a period of time
Coils test fine - until the fault occurs, then the issue repeats itself in test mode too (will stay up on power AND hold test).
Opto test fine, and issue stayed on same flipper after switching flipper optos round.
I haven’t yet gone straight into an Opto test directly after fault occurs - I’ll try that, I did start hammering the flipper buttons last time it stuck but that didn’t do anything.

Again cheers for all the help, any suggestions are welcome, frustrating but I do enjoy the learning curve.
 

Wizcat

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Would be nice to change the thread title to something more meaningful. There's a lot of good info here that might help future visitors, but they'd struggle to find it if the thread is just "Help please"
 
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Andydn

Andydn

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Would be nice to change the thread title to something more meaningful. There's a lot of good info here that might help future visitors, but they'd struggle to find it if the thread is just "Help please"
Yep can’t argue with that - done


Sent from my iPhone using Tapatalk
 

myPinballs

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Coils test fine - until the fault occurs, then the issue repeats itself in test mode too (will stay up on power AND hold test).
Opto test fine, and issue stayed on same flipper after switching flipper optos round.
I haven’t yet gone straight into an Opto test directly after fault occurs - I’ll try that, I did start hammering the flipper buttons last time it stuck but that didn’t do anything.

Again cheers for all the help, any suggestions are welcome, frustrating but I do enjoy the learning curve.
and when you switch off after this happens, the flipper immediately drops down to rest position?

Do you have another cpu and driver board to swap over and try ? If you want to send me them it i could try them in my gofers

I’d start by swapping the cpu first as it still sounds like a switch side issue
 

PBrookfield

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and when you switch off after this happens, the flipper immediately drops down to rest position?

Do you have another cpu and driver board to swap over and try ? If you want to send me them it i could try them in my gofers

I’d start by swapping the cpu first as it still sounds like a switch side issue
He said he swapped the flipper optos around and the issue stayed with the same flipper.

The fact that it's a warm-up related issue makes me doubt it's a transistor on the switch side (on the CPU board) - well, an IC or diode anyway, no discrete transistors in that pathway IIRC - the drive-side of things deals with a lot more power and is what I think is the bigger bet for having failed; either one of the transistors of the Darlington pair though it's almost always the main drive (not the pre-drive.)
 

myPinballs

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He said he swapped the flipper optos around and the issue stayed with the same flipper.

The fact that it's a warm-up related issue makes me doubt it's a transistor on the switch side (on the CPU board) - well, an IC or diode anyway, no discrete transistors in that pathway IIRC - the drive-side of things deals with a lot more power and is what I think is the bigger bet for having failed; either one of the transistors of the Darlington pair though it's almost always the main drive (not the pre-drive.)
I’m talking about lm339s on the switch circuit when I say ‘switch side’ not optos and they are on the cpu board for wpc-95

Transistors normally fail completely either open or dead short, whereas comparators can leak get stuck after being on for awhile

anyway feel free to ignore me and my advice... I’m just trying to guess at the most likely outcome to help the op out. It’s easily solved if I had the boards here
 
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PBrookfield

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I’m talking about lm339s on the switch circuit when I say ‘switch side’ not optos and they are on the cpu board for wpc-95

Transistors normally fail completely either open or dead short, whereas comparators can leak get stuck after being on for awhile

anyway feel free to ignore me and my advice... I’m just trying to guess at the most likely outcome to help the op out. It’s easily solved if I had the boards here
Nobody's ignoring you fella - in honesty I agree with you about the opto comparators being more likely than a partial transistor failure. Though transistor failure in this way is not impossible - AlanJ above has said he's had a case just like this. The coil getting hot made me think it wasn't a 'stuck switch' as it wouldn't get hot too quickly if it was stuck on with just the hold winding - and swapping the opto boards ruled out a strobing flipper opto signal for me.

And same here - looking at this in person we'd sort it out PDQ

My money is on Jim being right :D
Hopefully not purely because it's an easier soldering job to replace a transistor than a DIP14 IC - unless there's already been a replacement and someone added a socket!
But as long as someone's right and the game's sorted in the end, all is well!
 
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Andydn

Andydn

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Good news and bad news.
Other than unplug J120 and J119 to test the diodes (this was my way of taking them ‘out of circuit’ that in fact didn’t make any difference) I haven’t done anything too invasive but....
The issue seems to have stopped, been playing the **** out of it, using both flippers a lot and can’t seem to replicate the fault!
Good news but also frustrating as it may return, to be continued...... maybe
 

PBrookfield

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Good news and bad news.
Other than unplug J120 and J119 to test the diodes (this was my way of taking them ‘out of circuit’ that in fact didn’t make any difference) I haven’t done anything too invasive but....
The issue seems to have stopped, been playing the **** out of it, using both flippers a lot and can’t seem to replicate the fault!
Good news but also frustrating as it may return, to be continued...... maybe
I'm going to cry if it turned out just to be a dirty connector
 
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Durzel

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Stranger things have happened. Funky connectors and ribbon cables are the harbinger of random, unpredictable, inconsistent problems.
 
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Andydn

Andydn

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Just for anyone with similar issues, quite a few hours played now and issue still hasn’t returned. I’m guessing reseating connectors is quite a quick and easy first thing to try - seems to have been the cure in this case.
 

PBrookfield

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Always mad when it turns out to be connectors this late into a diagnosis session.

Hard reminder for us lot trying to help that we need to stop assuming that cables are being replugged / cleaned several times before we start sticking our oars in!
 

davro-one

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I had simular on my whitewater left flipper - turned out the coil sleeve had been put in from the wrong side - played fine for 10 minutes then started binding up - new sleeve / sorted !