(Topic ID: 249982)

Do pop bumpers weaken over time?

By paulace

2 years ago


Topic Heartbeat

Topic Stats

  • 20 posts
  • 11 Pinsiders participating
  • Latest reply 2 years ago by paulace
  • No one calls this topic a favorite

You

Linked Games

#1 2 years ago

I've been playing with removing layers of wire from the pop bumper coils in both Magic City and Slick Chick lately...and with great results. Both games are much more fun to play with the poppier bumpers. Slick Chick in particular was just brutal before the pop bumper improvements - not much movement in the upper playfield, almost impossible to hit that top center target, etc. After removing 2 1/2 to 3 layers of wire from the coils, there's much more action up there, the ball seems to spend more time in all areas of the playfield....it's just way more fun now and feels more balanced.

I went with removing wire from the coils because cleaning the metal slug/sleeve/moving parts of the pop bumper mechs didn't have much effect. So they weren't "weak" because of cumulative friction over the years.

Was the game designed with weak pops? I've heard Wayne Neyens say that of the games he designed, Slick Chick was his favorite game to play.... it's hard to believe that it was anyone's favorite game before making the pops stronger.

So I'm wondering - do coils weaken over the years? And if so, why? It's just a single piece of wire with a given resistance - that's not going to change, is it?

#2 2 years ago

The pops get weaker but I’ve never seen it be because of the coils. My dipsy doodle was very sluggish in the pops. After a rebuild they performed much better. See video below.

#3 2 years ago

It costs about $20 per pop bumper to rebuild them for this era. Not sure on slick chick.

#4 2 years ago

Rebuild is always step 1. That helps a ton. Just cleaning old parts is useless. It's also important on AC relay controlled pops to make sure the switches on the pop and relay are gapped well/close, and that the relay contact is nice and clean. I never resort to modifying coils

Quoted from chuckwurt:

It costs about $20 per pop bumper to rebuild them for this era. Not sure on slick chick.

Where's the $20 coming from? Coil included? I usually only spend a few dollars each on mine. New yokes, sleeve, plunger, spring. I should get a new ring but I'm cheap...

#5 2 years ago
Quoted from zacaj:

Rebuild is always step 1. That helps a ton. Just cleaning old parts is useless. It's also important on AC relay controlled pops to make sure the switches on the pop and relay are gapped well/close, and that the relay contact is nice and clean. I never resort to modifying coils

Where's the $20 coming from? Coil included? I usually only spend a few dollars each on mine. New yokes, sleeve, plunger, spring. I should get a new ring but I'm cheap...

Replaced everything but the coil. Bracket and ring too. Bracket is probably overkill, but mine were pretty rough.

#6 2 years ago
Quoted from chuckwurt:

Replaced everything but the coil. Bracket and ring too. Bracket is probably overkill, but mine were pretty rough.

Gottlieb kit is $10 for sleeve, stop, plunger, fiber and steel links and a spring.

Coil another $10.

Can't say I have noticed any get weaker with age, logic would indicate some resistance building up in the wiring over time and dirty contacts being a factor. Only time I noticed they were weak was when they had beat links, broken skirt, beat sleeves or wrong coil.

#7 2 years ago

In addition to the above mentioned mechanical issues contributing to possible deterioration of performance, a mushroomed plunger link that's dragging inside the coil sleeve would affect it.

Since this would happen over the course of years in a home use game, it may seem that the bumpers are slowly getting "weaker" as the mushroom/drag gets worse.

#8 2 years ago

No.

The just sell rebuild kits as another way to take your money.

#9 2 years ago

O-din's finally finished his first cup of coffee.

#10 2 years ago

Actually no coffee yet and I wish I was still in bed. But machines are coming and i gotta be awake for that.

But thanks for reminding me!

#11 2 years ago

Sleeves need replacing, skirts chip, caps break, bodies break, springs get cruddy etc. I rebuild with new pop bumper bodies, springs, caps, rings/rods, etc. The only thing I don't replace is the coil and the bracket. I'll reuse the yokes if they're not broken. Clean switches are a big component of that as well. not only does it look nicer, it is much peppier. I've never modified coils to make them perform better.

#12 2 years ago

On system 6 to 11 replacing the cap on the switch seems to help as well.

#13 2 years ago
Quoted from o-din:

No.
The just sell rebuild kits as another way to take your money.

Rebuild kits have their place- On my Hearts and Spades it had been flogged for so long that every single fiber was destroyed, the counterpart metal piece was broken in two and the plungers were wrecked and one skirt was busted. Otherwise I do it piecemeal as I have a large selection of parts built up at this point

#14 2 years ago
Quoted from FatPanda:

I'll reuse the yokes if they're not broken.

Metal one is probably okay, but I've seen a lot of fiber ones that have actually been beaten thinner slightly. I assume that you want the least play possible, so I always put in thick new ones

#15 2 years ago

What I did before playing with the coil wrappings was: took mech apart, got rid of any mushrooming at the end of the slug, polished it with mother's/steel wool/microfiber until it was nice and shiny and smooth, replaced the sleeve, smoothed the top of the coil stop/cleaned it, cleaned and polished the steel bumper - again, mother's and steel wool (don't worry, I don't use steel wool over the machine - I take it outside for that), cleaned the yokes, cleaned the bottom of the spoon switch (and all other switches) with the dremel/alcohol, cleaned the bottom of the skirt that sits in the bottom of the spoon, cleaned the spring.

With that - not much change. Everything felt nice and smooth - nothing binding or tight....just not very powerful. So I went with unwrapping the coils and bingo - like night and day. I'd heard that Steve Young sells stronger pop bumper coils, but some folks said they were too strong, so I tried doing it manually. I'm very happy with the results.

#16 2 years ago

There are several guide out there on tuning up pop bumpers. Check pin Wiki or clay Harrell's site or look for threads on pinside. Most important thing are clean switches and no extra play between the yolk parts and the plunger. That is where you're losing a lot of efficiency. I never mess with used yokes. If there is any play where they fit on the plunger, replace that as well.

#17 2 years ago
Quoted from paulace:

What I did before playing with the coil wrappings was: took mech apart, got rid of any mushrooming at the end of the slug, polished it with mother's/steel wool/microfiber until it was nice and shiny and smooth, replaced the sleeve, smoothed the top of the coil stop/cleaned it, cleaned and polished the steel bumper - again, mother's and steel wool (don't worry, I don't use steel wool over the machine - I take it outside for that), cleaned the yokes, cleaned the bottom of the spoon switch (and all other switches) with the dremel/alcohol, cleaned the bottom of the skirt that sits in the bottom of the spoon, cleaned the spring.
With that - not much change. Everything felt nice and smooth - nothing binding or tight....just not very powerful. So I went with unwrapping the coils and bingo - like night and day. I'd heard that Steve Young sells stronger pop bumper coils, but some folks said they were too strong, so I tried doing it manually. I'm very happy with the results.

Soo.... You didn't rebuild it. You can't expect parts that have been wearing for 50 years to work good as new just because you cleaned them. Even if nothing is catching, the plunger is never going to be as smooth as when it was new. The spring will be weaker. The yokes will be worn. It all affects the action

#18 2 years ago
Quoted from paulace:

So I'm wondering - do coils weaken over the years? And if so, why? It's just a single piece of wire with a given resistance - that's not going to change, is it?

Unless the coil has been abused (overheated, dropped, etc.) I don't think it weakens with time or use. I agree with you, I don't think copper in this application wears out.

I also agree that removing some loops from some coils strengthens them. That's not a general rule of thumb though because the relationship between number of loops and coil strength is complicated. If it were a simple relationship you could keep removing loops and keep making the coil stronger. Yet with just a loop or two left the coil should be at its strongest but instead it would be useless.

So removing some coil loops usually does make things snappier even if there are other issues that haven't been identified or addressed.

Cleaning and/or replacing parts as others have mentioned is usually a good place to start to restore pop bumper (or sling shot, or flipper, etc.) power. But an often overlooked component to coil performance is the duration of the pulse that fires it. Pop bumpers only get a very brief pulse when they're working well. If that pulse is narrowed that effectively cuts the power that the coil can deliver to the ball (through the plunger and pop bumper ring). Clean contacts are important but if the switches involved in delivering a good pulse to the pop bumper aren't properly adjusted the coil will seem weak.

zacaj briefly mentioned gapping the relevant switches. But also check that your EOS switch opens at the last possible moment since that cuts power to the pop bumper. Also check the contacts on the high current pop bumper relay switch (the one with the larger contacts) that sends power to the pop bumper coil. And less common but still possible is that the bumper isn't assembled correctly. If the fiber and metal yolk are put back in the wrong order for example, the EOS switch might open too soon, cutting off power too early.

I get that some prefer hotter coils and that's fine. But in most cases I want to believe that if a coil isn't doing what it should there's something (probably a few things) in its 40+ year history that's compromising its performance.

/Mark

#19 2 years ago

Everything wears down over time...everything.

You just need a rebuild kit.

#20 2 years ago

Thanks MarkG. I understand just enough about coils to realize that there is a point of diminishing returns - that removing loops (resistance) only works to a point, then at some point you have removed enough loops to weaken the magnetic field and are being counterproductive. Apparently, 2 1/2 layers of wire hasn't hit that point because the pops are significantly stronger, but not ridiculously so to a point that would be inconsistent with what I imagine the speed of the game should be - I don't want it to play like Metallica. I was trying to find a balance and I've been happy with the results - it feels like "customizing" the strength of the pops. I actually did it in stages as I was nervous about it - tried 1 1/2 layers, then 2, then 2 1/2 before it felt "right".

I agree that the cleanliness of the contacts and gapping of them is critical. I did take some time to make sure the EOS switches were opening late-ish - made sure to clean the contacts in the relays associated with each pop as well. I chose not to re-build the mechs because I thought the original parts were in very good shape and cosmetically, the blue plastic had this marbled look that I really liked, and wasn't reproduced in new plastics - so I chose to clean and polish what was there. Granted, there will be some friction that wasn't there originally, but what I was concerned with mostly was whether there was significant slop in the linkage to the slug or the yoke (there wasn't), getting rid of any corrosion on the metal parts, getting dirt off the plastic parts and out of joints - basically, anything that I thought would cause friction - and re-soldering the connections to make sure I had good electrical flow.

To do a meaningful comparison, I probably should have rebuilt one or two pops with new parts with the coils in their original state, and seen what difference that made, but it's a bit late for that now....next time.

And I agree with the general concensus that actually rebuilding the mechs with new parts is the only way to truly assure the least friction and most efficiency. I chose not to do that for my own reasons. My original question was whether or not the actual coils themselves could weaken over time. I didn't see how that could be, (I mean, it's a single piece of wire with about 2.4 ohms resistance....how much could that change even over 55 years), but thought I'd ask as there are some pretty smart folks out here in forum-land. If I'm understanding you correctly, there shouldn't be much change in the strength of the actual coil.

Thanks for all the responses - it's always educational!

Hey there! Got a moment?

Great to see you're enjoying Pinside! Did you know Pinside is able to run thanks to donations from our visitors? Please donate to Pinside, support the site and get anext to your username to show for it! Donate to Pinside