(Topic ID: 186851)

PinBot Right Flipper Sticking Pop Bumper Not Poping

By spjohn1964

2 years ago

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  • 15 posts
  • 5 Pinsiders participating
  • Latest reply 2 years ago by spjohn1964
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#1 2 years ago

Hi there,
1st I am pretty new to this forum. I joined when I was in search of my 1st pin. I am super new in pinball machine ownership. I did find the machine of my dreams "PinBot" right from this site. When I tested the machine prior to purchase it worked flawlessly and over all is a very clean fine specimen from an era long gone. PinBot had to take a 2 1/2 hour truck ride which I padded the bed wrapped in furniture blankets and a tarp then gently secured with ratcheting straps. Got it home and in it's new spot fired it up let it go through it's warm up sequence. Well 1st thing I notice the lower pop bumper is a bit lazy as it took being struck with moderate force by ball to engage. No biggie I figured a little adjustment needed after the long trip. Well I am playing the $#!t out of my new toy all weekend and the pop bumper becomes completely dead. So I start researching how to remedy. I am also seeing a message on the alphanumeric display during warm up "bottom jet".So yesterday day 3 of ownership I notice a pronounced humming sound from the right flipper when button pressed or held in the up position. There seems to be no loss in strength but I notice arcing coming from the contactor at the flipper button. I can see it through a little slit by the ball launch. Knowing enough about electricity to get me in trouble I do know arcing is more than likely not a good sign especially with this new humming sound. Again I start a new path of research on flipper humming. So today as any newbie would do I fire up the machine just to see if it fixed itself lol. Well after warm up I hit the right flipper and yes it still arcs and hums and now it is stuck in the up position (and stays when I power down). So I pull the glass and raise the play field. When I work the plunger back and forth it definitely sticks in the solenoid at the end of the stroke. Then when I examine the paddle switch the primary contact comprised of 3 paddles contactors does not open because one of the paddles that is supposed to be attached to the second paddle (with contact) is broken and not allowing the contacts to separate. Also through manual manipulation and using the left flipper switch as a guide the secondary paddle is barely making contact when flipper is it the up position. I understand that second switch is vital for keeping power level if player holds flipper up to trap ball. I am mechanically inclined and knew the eventuality of pins being a matter of "when not if" repairs will be needed. I was hoping I would have had more time to enjoy my pin before crippling problems arose but it is what it is. I have to admit I am a bit intimidated by this situation and do not want to end up doing more damage trying to make a 1st time repair. I realize this topic has probably been discussed many, many times but any info and insight would be greatly appreciated.
Thanks in advance

#2 2 years ago

Start here for the pop bumper. Probably needs the spoon switch adjusted.


For the flipper. If mechanical can be a couple of things. A little research or manual reading will show you how to drop the basic mechs of the flipper to check.

Check the Nylon coil sleeve that it is clean and comes out of the coil easy. And check the coil stop. These are the easy two things to check.

#3 2 years ago

Thank you for your reply and link. I have seen that wonderful article and will more than likely use it as a reference guide when I get the flipper issue corrected. I can play without a pop bumper but not without an operating flipper lol. One thing I failed to mention in my 1st post. The wire block behind the solenoid appeared to have excessive play and overall the same could be said about the entire mechanism compared to the left side.

#4 2 years ago

If by "wire block" you mean the coil a picture would help. Do you have a manual? The flipper assembly in on page 49 of this PDF.


Using a hex wrench you can remove two bolts and drop the coil stop at the back of the coil. You do not need to disconnect the wires or anything to check these first few parts. Just remove that plate and slide the coil off the plunger.

The plunger smacking against it makes it mushroom. The flattening can cause magnetism and sharp edges that distort that nylon coil sleeve the goes through the coli. These are those first two parts to check. If that coil got too hot at some point the coil sleeve can warp and grab the plunger causing the hang.

There is more, but learn the basics of the parts and how they function. Look for signs of too much dirt, cracks . . . Read up.

#5 2 years ago

Page 43 of the manual, shows the flipper assembly. You might just need to rebuild it. not hard or overly expensive.

#6 2 years ago

Through the magic of YouTube I have a much clearer perspective of what I need to do to fix the flipper. I now realize the "wire block" are the coil wires themselves. The mechanics of the whole mechanism seems to be simple enough. I know I will have to address the situation with the end of stroke switch. It appears the one of the paddels that is disconnected acts as a spring of sorts to keep the contacts open (not touching). As it is now the contacts are closed (touching) throughout the entire range of motion. As I mentioned I have the left flipper assembly to visually dissect for reference. I am just wondering if the the situation with the right flipper end of stroke switch was the cause or affect of the flipper problem. I am still not as clear with the pop bumper but I do know that I will have to remove the upper deck bagatelle to fully remove the pop bumper. I do not have the original manual but I have a downloaded version which as it stands now is a lot of Greek to me lol. Thank you again for all the info and maybe more

#7 2 years ago

The pop bumper should be adjustable from underneath without removing anything (as long as nothing is broken). The ball hits a plastic ring known as a skirt. The skirt moves a prong in a "spoon" attached to a leaf switch. Make sure the moving of the skirt makes the spoon close the gap properly.

Area of concern circled.

pop (resized).jpg

#8 2 years ago
Quoted from spjohn1964:

I am just wondering if the the situation with the right flipper end of stroke switch was the cause or affect of the flipper problem.

It was the cause of the coil getting too hot and now the sleeve is melted causing the flipper to stick up.

#9 2 years ago
Quoted from GRUMPY:

It was the cause of the coil getting too hot and now the sleeve is melted causing the flipper to stick up.

What Grumpy said. Good news is that its a .50 fix after the end of stroke switch is adjusted properly. (plus shipping)

#10 2 years ago

Thanks guys! I really appreciate all the advice and the wonderful pop bumper diagram. Thanks Taxman Does any one have a link or location to aquire the coil sleeve and new coil stop?

#11 2 years ago

One more thing. If the new coil sleeve does not slide in to the coil without force the coil itself may have warped. But don't worry about that until you try the new sleeve.

There are a few places to get these parts. Pinball Life is a good one.

Coil Stop -> http://www.pinballlife.com/index.php?p=product&id=977

Coil Sleeve -> http://www.pinballlife.com/index.php?p=product&id=90

The quick of how the flipper functions. The coil is getting high and low voltage when you hit the button. The high voltage makes the flipper snap hard to hit the ball. The end of stroke switch cuts off this high power and leaves the low voltage to hold the flipper up without overheating the coil. When the EOS does not function the longer you hold it up the hotter the coil gets. This will ruin the coil and when it shorts blow the fuse.

If the coil ever is bad -> http://www.pinballlife.com/index.php?p=product&id=8

And for the future. You can do an entire flipper rebuild on both for around $25 ->

#12 2 years ago

Thank you for the links Taxman, I went ahead and ordered the twin flipper rebuild kits. I figured if I got into the disassembly and discovered additional mechanical issues I would be prepared. I also figured all good pinball owners have some sort of collection of spare parts lol. I am going to see if I can revive the pop number issue with the adjustment advice you provided earlier. My flipper parts will be here in a couple of days. Oh and I am more than certain the flipper coil itself is fine as the flipper did start working without sticking in the up position. It still makes a pronounced humming noise when used but I did play a couple of games to get my fix . I am going to try my best not to use it until I can make repairs. I am going to try my best, try my best, try my best...

#13 2 years ago

One last piece o advice. Do not lubricate anything. It will just turn into a sticky / clump. Very few assemblies in pinball require lubrication and they will be clearly defined in the manual.

Good luck.

#14 2 years ago

Yes I have read that about lubrication. Frim what I have seen only the ball kick (to launch) needs lube in 2 spots. I have seen asvice to use silicone spray on the plunger rod. It is a dry non petroleum lube that is to only be used at assembly time of the mechanisms.

#15 2 years ago

Well I got my flipper rebuild kit from Pinball life today. So when I got a chance in the evening I got straight to work. Well the coil sleeve did not slide out it was pretty much stuck. I by gently tapping from the opposite side of the flanged end got it to move but there was no way it was going to come out easy. I thought I would be smart and use one of the new coil sleeves to drive the old one out. It really was working well until I realized the new sleeve was being shredded inside the coil. So with the old sleeve 1/2 way out but still not pulling out I resorted to finding a socket that the OD almost matched the ID of the coil cylinder. So after getting the old sleeve out I cleaned the coil cylinder with some denatured alcohol. However the the new sleeve was very tight going in (that's what she said lol) so I resorted to using a furniture clamp to "press" the sleeve in the coil. The existing plunger did not have any "mushrooming" but the coil stop did show signs of it. The stop was a no brainer to replace. The existing plunger slid effortlessly in the new sleeve. Then I replaced the EOS. While doing so I realized the reason the large contacts were not opening (separating) was due to the switch paddle broke at the point of contact. So there was nothing for the tang on the flipper position lock to strike. After resoldering the wires to the new switch I did have to reposition all the components as I realized I had assembled all the components on the wrong side of the mounting bracket. Anyhoo the flipper now works like a dream! I know I still have an issue at hand with the coil as my understanding is the sleeve should slide effortlessly in the coil cylinder. But as of now the flipper is performing as one would expect. I did also do some adjustment to the pop bumper and it has come back to life somewhat but still not as sensitive as it should be, I will attempt more adjustments. I want to thank all of you for helping me through he woods with this issue. Even though I know I still have a potentiality issue looming with the flipper coil I feel as if I am now a "pinball fixer" I couldn't have done it without all the wonderful advice here in this thread but the forum as a whole.
Thanks again

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