Pop-bumper's sticking

[MartyJ]

Hi guys,

I look the plunge today and fired up the Black Hole (on test bench setup)...No fire or bangs which is good.  Some of the G.I lighting is out but I'll hunt that down later.  Pretty much everything is working well but some of my pop bumpers are sticking....

It does not seem to be the actual coil locking on as I tested on the lower one (top pf)...I would activate the pop bumper and it would stick...I would remove the plug from the pop-bumper board (thus removing power) and it continued to stick.  A slight vibration on the playfield would send it home!

From a bit of reading it seems that the plunger / bracket can become magnetized?

Has anyone else had this problem and any solutions (other than buying new brackets/plungers)?

Regards

Marty

[pinballist]

It wouldn't be the plunger sticking inside the coil sleeves would it?

[Retropin]

Im with Evro,

Id be VERY suprised if it was the bracket being magnetised. Thats the fix that you do when you eliminated all other options.
Always start simple.
Chances are that you have dirty coil sleeves which can be cleaned with a touch of metho, or the spring on the plunger is getting caught in the fired position

[Marty Machine]

Besides the typical Dodgy insert that keeps grabbing hold of the plunger.....
I found my main 'sticky' bumpers were issues with the "ring & rods" piece:

1) Rods covered in oil/dirt and binding within the playfield wood (perhaps oil swelled the ply, choking around the rods?)
2) Rods binding against the playfield hole, due to mis-aligned mounting of bumber metal bracket
3) Ring/Rods slightly bent from ball slam or owner mis-handling them/alignment?

Also replace the saggy return spring.

I haven't seen the magnetised problem before...

I rebuilt all mine as a total overhaul (i think the only original parts are the coils and main mounting bracket).
I figured if i'm going to the effort to pull apart the bumper to replace an insert sleeve, i may as well refresh the fiber yolks, rods+ring, springs etc etc.

It's amazing how much snappier they become, almost scary.

MM.

[MartyJ]

I'm a little puzzled as well.

During rebuild, brackets soaked and cleaned very well.
Plungers cleaned as well as plunger and yokes.

Brand new coil sleeves too?

If I move it all my hand, is very smooth and spring works well too.....

[Strangeways]

I,ve seen the magnitism problem once before, but on an outhole (rocky). The plunger would stick. Took me hours to work it out.

The problem was that the previous "tech", had replaced the coil bracket with a bracket from an EM. So every time it fired, it held the plunger in. The smarty "tech" screwed a wood screw into the underside of the playfield so the plunger did not travel all the way to the coil stop - because it would then stick.

Using a coil bracket from an EM (AC) in a SS (DC) will cause this problem of the plunger sticking.

[MartyJ]

I've noted from the parts manual there are two types - AC & DC.  I'm reasonably confident I've eliminated the above suggestions and I've just pulled out apart again to double check.  Everything is moving freely by hand.

There are no part numbers on the brackets unfortunately, so I cannot eliminate these as yet.  On RGP there are quite a few posts in relation to this exact issue and one of the suggestions is to replace the plungers (as they also magnetize).  These are cheap and easy (and sourced locally thanks to RTBB!) so I'll give these a go first then take it from there.

[ddstoys]

I had this same issue on Close Encounters but it only happens when actuated by hand does it still get stuck if you use a ball?

[MartyJ]

I had this same issue on Close Encounters but it only happens when actuated by hand does it still get stuck if you use a ball?

Unfortunately yes...

I've checked and no switches are getting stuck either......Tried a new plunger, no different...   

Next step ...unsure...

[ddstoys]

Make sure the main bracket is straight if its bent the plunger will bind as it goes in on an angle.

[MartyJ]

Make sure the main bracket is straight if its bent the plunger will bind as it goes in on an angle.

When activating the unit by hand, works perfectly every time and never sticks...

I'm leaning towards the bracket assembly becoming magnetized...I am out of ideas otherwise..

[ddstoys]

remove the coil and add a put a few bits of paper over the coil stop this should be enough to break the magnatism if there is any at least then you will know

[MartyJ]

remove the coil and add a put a few bits of paper over the coil stop this should be enough to break the magnatism if there is any at least then you will know

Will do tomorrow.  Had enough tonight, but the good news is I fixed the G.I problems (x2)....Top playfield had no G.I...Searched and searched and found the relay which turns it on and off, the return wire had broken off.  Easy fix.  Lower pf....The relay under there, was working but dirty contacts...Cleaned and all good now!

Next issue - (other than pop bumper) is the lower playfield lighs (playfield window) are not lighting up.  This may be related to the same relay.  Will know in morning...!

[Retropin]

A little tip Marty.

If it is magnetism and i have had this myself but on a 50's game that has seen many more years of current through it.
On a DC coil... now Genco had DC coils which are a straight coil larger than standard with a DC supply, if you reverse the polarity it de magnetises the bracket and stop, takes a while but it does work.

 In fact, thinking on it, you can put it on a battery charger with the polarity reversed and demagnetise... mmm simle cure!


aaaah also... to test it is magnetised just put a very small piece of iron on there before going to any effort.. i only found out that this was my problem cos the screw attached itself to the bracket.


.. sod this... give another beer

[ddstoys]

Reverse the polarity BLOODY BRILLIANT IDEA but not nearly as good as another beer (JW)