(Topic ID: 233313)

1974 Williams SkyLab left flipper weak. Please help

By StotzBotz

5 years ago



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#1 5 years ago

Hello friends. I was wondering if anyone knew a solution to a problem I'm having. I have a 1974 Williams Skylab EM pinball machine that I purchased recently. The guy I got it from did tell me that the left flipper seemed weak sometimes although shortly after I tried playing it the flipper was constantly very weak compared to the right flipper. After inspecting the assembly I noticed that the left flipper coil had been replaced. The number on the old coil on the right flipper is FL20 28-400. The number on the new left coil was FL20-300/28/400. I'm wondering if this is the right coil for this machine as the number isn't exactly the same as the old right coil that's original to the machine. If it is correct then why is the action of it so weak. If I try to hold the right coil plunger mechanism when I activate it my hand practically gets ripped off. If I hold onto the left flipper it buzzes and is quite weak. Any help in figuring this out would be most appreciated.

#2 5 years ago

Make sure the end of stroke contacts are adjusted correctly.

#3 5 years ago

Thank you. It appears as though the end of stroke switch is damaged and is making a connection which is not enabling the high voltage to work the flipper properly.

#4 5 years ago

I separated the eos switch so no contact is being made but there is still no change. I'm stumped.

#5 5 years ago
Quoted from StotzBotz:

I separated the eos switch so no contact is being made but there is still no change. I'm stumped.

EOS is a normally closed switch. Only opens when the flipper goes up.

#6 5 years ago

Another thing to try is swapping the flipper coils.

#7 5 years ago

You can also clean the plunger and sleeve with a swab and 91# rubbing alcohol, then give the plunger a quick sanding with 600# paper.

#8 5 years ago
Quoted from Brypten:

EOS is a normally closed switch. Only opens when the flipper goes up.

Brypten is correct. Until this is correct, the rest of the diagnostics will be less meaningful. With an open switch you will only get the hold power.

Dave

Skylab (resized).pngSkylab (resized).png
#9 5 years ago

Thanks everyone. Here's the weird part. If I look at the EOS switch on the right flipper which is working correctly, it has a very small gap between the points so they are actually not touching. I just took a set of hemostats and clamped the switch EOS together on the left flipper and it works fine now. Yippee. I will order a new switch from Pinball Resource. Why the other one works fine without the contacts touching makes no sense.

#10 5 years ago
Quoted from StotzBotz:

Thanks everyone. Here's the weird part. If I look at the EOS switch on the right flipper which is working correctly, it has a very small gap between the points so they are actually not touching. I just took a set of hemostats and clamped the switch EOS together on the left flipper and it works fine now. Yippee. I will order a new switch from Pinball Resource. Why the other one works fine without the contacts touching makes no sense.

I would guess continuity is being made somewhere else.. Lest and right are wired the same. EOS should be normally closed. If you have a DMM check for continuity across the jumpers on either side if the EOS. I would guess the blades are shorting even if there is a gap at the contacts.

Dave

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