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WPC flipper question

Chris Bardon

Well-Known Member
Nov 15, 2012
1,303
165
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Mississauga, ON
So I noticed something strange on my TZ last night when I had a bunch of people over, and that's where the left flipper would stop returning to its home position after the game had been up and running for a few hours. I let the machine cool off a bit, started it up again, and it was fine for another hour or so, when the same thing started happening again. The last time I had a problem like this I threw in a whole new mech from a rebuild kit and everything was fine, so I could just do the same thing, but I'd like to figure out why this is only happening after the game gets warm. Given that the left and right mechs have the same coils and sleeve types, I'd assume an even thermal expansion on both sides, so maybe just extra crud in the sleeve causing that much more friction, or a slightly more worn return spring that isn't able to overcome the extra force?

Anyway, just curious what you guys do in a situation like this-just replace the whole mechanism or try to do it piecemeal? No reason to just throw parts at problems that don't require them.
 

Vengeance

Well-Known Member
Nov 14, 2012
1,990
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Keswick, ON
I should have said his last night, check the EOS

If the EOS isn't working right, the coil would be heating up after a bit of playing which could cause it to start binding.

I remember touching the coil and it wasn't too hot, but the coil stop was.

also take apart the mech and see if you can remove the coil sleeve, if it's stuck in there, that means the coil has expanded and that would be where the binding is coming from once it heats up.

You would have to replace the coil at that point.
 

Chris Bardon

Well-Known Member
Nov 15, 2012
1,303
165
63
Mississauga, ON
Thanks, I'll check those out. I thought of the EOS, but won't that usually throw a credit dot up? Perhaps if it's only registering 50% of the time it's not enough to generate an alert, but enough to heat the coil more than it should?

Something else that can cause this is improper flipper bat to bushing gap.

You're talking about the vertical play that you have with a flipper once it's tightened in place? Is there a proper way to measure what that should be? Anytime I've ever replaced flipper mechs, I've left it with a few millimeters of movement so it's not overly tight, but the amount is pretty arbitrary and is really just whatever feels right (not dragging against the bushing or PF, but pawl is still moving straight into the coil).
 

Menace

Well-Known Member
Staff member
Nov 14, 2012
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Santiago de Aurora
Games used to come with a flipper gap gauge, but usually these are long gone. Good rule of thumb is the gap should be two business cards thick. Too little gap and it drags, too big a gap and it tends to bind but it usually doesn't happen until you've been playing for a while.

I'm thinking the EOS is still a more likely source of the issue though, as it sounds as though the coil is swelling over time.

D
 

Chris Bardon

Well-Known Member
Nov 15, 2012
1,303
165
63
Mississauga, ON
Tested last night in the switch test, and 20 or 30 cycles of the flipper all activated the EOS switch correctly. Holding the flipper button also kept the EOS on, so it doesn't seem like it was stopping. Is it possible that the EOS could register in the test, but not actually be doing anything?
 

Vengeance

Well-Known Member
Nov 14, 2012
1,990
138
63
Keswick, ON
Just cause the EOS is working now doesn't mean it didn't stop working as some point, take apart the flipper assembly and see if your coil has expanded.

If you can't remove the coil sleeve, you have your answer.