Diode on Flipper Coil Question

0

#1 4 years ago

OP

???

nwkadm

Inactive member

Unknown

8y 16,400 90 1

I have an Eight Ball Deluxe LE and have a question about the diode's on the flipper coils. The 2 left flippers work fine and when I measure the diode's on these flipper coils (with meter in Diode mode), both read .2 for the left diode and 0 for the right with continuous beeping - the right flipper reads .2 for the left diode and .188 for the right diode - continuous beeping for the left diode and only beeps once on the right diode.

Is this indicating that the right diode on the right flipper coil is bad and if so, what causes these to fail - is there a common issue that would cause this?
(When I measure these diode's in Ohm mode on the meter, I get 3 ohms for the left diode and .2-.5 for the right diode (Left 2 flippers) and on the right flipper, I get 3 ohms on the left diode and 310 on the right diode).

The right flipper does not fire when the switch is pressed - both left flippers work fine. When pressing the right flipper switch, I feel vibration on the flipper bat but it will not work.

TIA

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1

#2 4 years ago

AXE

YeOldPinPlayer

Inactive member

Unknown

8y 111K 6,454 4 12

Are you trying to figure out why the flipper isn’t working? A bad diode won’t cause that.
https://www.pinwiki.com/wiki/index.php?title=Common_Flipper_Troubleshooting#Missing_diode

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#3 4 years ago

PIP

Quench

Pinside member

8y 114K 8,039

OP
Quoted from nwkadm:
(When I measure these diode's in Ohm mode on the meter, I get 3 ohms for the left diode and .2-.5 for the right diode (Left 2 flippers) and on the right flipper, I get 3 ohms on the left diode and 310 on the right diode).

The right flipper does not fire when the switch is pressed - both left flippers work fine. When pressing the right flipper switch, I feel vibration on the flipper bat but it will not work.

These readings indicate classic End Of Stroke (EOS) switch issue with your right flipper. This EOS switch is "normally closed", and opens when the flipper reaches full stroke. Yours is not making proper contact. The contacts on the switch are tungsten and may need to be filed clean/flat to make better contact and/or the switch blades need to be better pressed against each other. Or you could just replace them if they're in bad shape.

These flipper coils are made up of two windings. One is a high current winding to thrust the ball, the secondary winding is low current and used to hold the flipper up. The EOS switch is wired directly across the hold winding and effectively shorts it out so that when you press the flipper button, only the thrust winding is active. When the flipper reaches the end of stroke and opens the EOS switch, the hold winding now gets added to the flipper circuit to reduce current and prevent the thrust winding from cooking.

Notice your working left flippers right side diodes measured 0.2-0.5 ohms (EOS switch was closed shorting those lugs) while the right flippers right side diode measured 310 ohms because the EOS switch wasn't closed/making contact.

Hope this helps.

0

#4 4 years ago

OP

???

nwkadm

Inactive member

Unknown

8y 16,400 90 1

Quoted from Quench:
These readings indicate classic End Of Stroke (EOS) switch issue with your right flipper. This EOS switch is "normally closed", and opens when the flipper reaches full stroke. Yours is not making proper contact. The contacts on the switch are tungsten and may need to be filed clean/flat to make better contact and/or the switch blades need to be better pressed against each other. Or you could just replace them if they're in bad shape.
These flipper coils are made up of two windings. One is a high current winding to thrust the ball, the secondary winding is low current and used to hold the flipper up. The EOS switch is wired directly across the hold winding and effectively shorts it out so that when you press the flipper button, only the thrust winding is active. When the flipper reaches the end of stroke and opens the EOS switch, the hold winding now gets added to the flipper circuit to reduce current and prevent the thrust winding from cooking.
Notice your working left flippers right side diodes measured 0.2-0.5 ohms (EOS switch was closed shorting those lugs) while the right flippers right side diode measured 310 ohms because the EOS switch wasn't closed/making contact.
Hope this helps.

Thanks Quench - that solved the issue and the right flipper is back working. The flipper was a little weak so I made a little more adjustment to the EOS and it is working good now except that every once in a while, the flipper will stick in the up position until I hit the button - if this still related to the EOS and more adjustment is needed?

0

#5 4 years ago

OP

???

nwkadm

Inactive member

Unknown

8y 16,400 90 1

Quoted from YeOldPinPlayer:
Are you trying to figure out why the flipper isn’t working? A bad diode won’t cause that.
https://www.pinwiki.com/wiki/index.php?title=Common_Flipper_Troubleshooting#Missing_diode

Thanks for the link - good info.

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2

#6 4 years ago

TOM

pinballinreno

Computer Extreme

9y 134K 15,522 31

Does the flipper stay up if you turn off the game while its stuck?

If it stays up while powered down its a mechanical linkage problem

0

#7 4 years ago

OP

???

nwkadm

Inactive member

Unknown

8y 16,400 90 1

Quoted from pinballinreno:
Does the flipper stay up if you turn off the game while its stuck?
If it stays up while powered down its a mechanical linkage problem

I will check and get back with you on this.