a new (for me) cause of a sticky flipper

[cooldan]

flipper kept getting stuck in the up position. power off, it stayed up, so i knew it was mechanical. i'm familiar with mechanical sticky flipper from lots of causes but this was a new one on me.

first thing i did was take the end stop off, take the sleeve out. usually a ratty plunger needs a quick rub down with emery paper to get the chuff off, and a new sleeve means next to no friction. so i did those but no change, still sticking.

next up, return spring or cushioning grommet? i've had slack springs be the culprit before, and old grommets going gloopy and sticky like chewing gum - but these were just fine.

binding? is the flipper sticking to the playfield on top, or to something underneath in the vertical plane? nope, i could lift the flipper up and down a little bit so that wasn't it - and this was happening without the game needing to get hot first, which is a good symptom for diagonising a binding problem.



i was flummoxed til i had another good look at the old sleeve and noticed it had bite marks out of it. not literally bites, but it was getting attacked in one specific place.sure enough when i looked at the plunger link, i could see the problem - the link itself was pushing itself into the sleeve and getting a bit of purchase, and now the shoulder of the link was all chewed and would carry on doing it, even with my new sleeve. solution: new plunger and link.



that's it. not very exciting for those of you who've done loads and loads of flippers, but a journey of discovery for me, still a bit green and wet behind the ears even after a few years and a few dozen machines.

as you were


edit: colour coded the flipper parts to match the pic in the next post down with coloured circles and ellipses on it

 

[cooldan]

oh, i forgot to mention that i also needed to transfer across the little metal grommet that sits in the middle of the link piece, otherwise the pawl piece (the bit that attaches to it) won't be able to grab it properly and it still able to rotate. i neglected this the first time until i saw it sitting there looking at me questioning me.

so here is the new shoulder that doesn't stick, vs the old shoulder dystocia

and here are all the bits to check when you have a sticky flipper that's mechanical - the white arrow is the new one i just added

 

[Carl Spiby]

Was the end stop worn as well? The link shouldn't be impacting the end of the coil sleeve at all.

 

[cooldan]

the end stop was fine. what do you mean the link shouldn't be impacting the sleeve?
it was - look:


oh, and i could add another colour arrow to that picture above - the bushing (round blue thing just above the yellow circle, that the flipper bat goes through the playfield inside). it doesn't cause sticking that i ever saw, but when that hollow tube becomes a slack ellipse like a wizard's sleeve or like Kerry Katona's lady parts, it needs to be replaced as there will be too much play

 

[pinballmania]

Compare the length of the old plunger with a new one. Once the bevel is worn away it's time for a new plunger and end stop. If you keep grinding a new bevel it'll just get shorter and shorter.

 

[JT.]

Had something very similar happen in my Alfa Brera a few years ago, with the lower part of my windscreen wipers gnawing through a pipe that transported the gas for my aircon - hungry little devils.

Is the shift key broken on your keyboard?

 

[Moonraker]

Looks like the old coil sleeve may have been too long...

 

[cooldan]

i'm hearing the plunger may have been too long, and/or the sleeve may have been too long (hope not, as i replaced with identical sized parts), as the link isn't supposed to meet the end of the sleeve. but i don't understand how that could be, as all sleeves are supposed to protrude through the ringpiece (pffftm stop it, er, @Paul) and i just checked flipper coils on a BWS and a Stern game and they are the same as this DE one, the shoulder of the link always abuts the ringpiece (pffft), which the sleeve pokes through. so ner ner ni nerner and yah boo sucks.

anyway it doesn't matter cos it's fixed now, it just pointed out to me that there's a million things can go wrong on this ****ing things we all love so much

 

[Paul]

you said ringpiece.....

 

[pinballmania]

Your old plunger will be visibly shorter than a new one. So the excess travel drives the link further into the protruding coil sleeve.