(Topic ID: 98362)

WW Tech help: Flippers trigger flashers???


By 27dnast

4 years ago



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  • 20 posts
  • 9 Pinsiders participating
  • Latest reply 81 days ago by kbliznick
  • Topic is favorited by 17 Pinsiders

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System 11 Flasher fix board only (resized).jpg
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#7 4 years ago

Nothing wrong with the game.

This is what happens to all system 11B and 11C games (with the Aux driver board) when you install LED flashlamps into solenoid spots 3,4, 6 and 7.

There are tie-back diodes on the large TIP36 transistors that connect those circuits to the 50V power source. There is a some feedback into these circuits from the flippers that is not apparent until you install LED's.

To fix this, Cut diodes D3, D4, D6 and D7 from the aux driver board. Then add diodes onto the coils for solenoids 3,4,6 and 7 (banded end of the diode goes to the power wire)

#9 4 years ago

I believe any of the 1N400X will work. I usually use the 1n4007's

#13 4 years ago

modifying the board and coils will still allow you to put incandescents back in. This was just an error in placement by Williams.

Alternatively you can leave the diodes on the board and modify the board. If you look at the schematic you just need to move the unbanded end of the diode to the other side of the resistor that it connects to.

4 years later
#17 11 months ago
Quoted from tdk999:

What if you leave the diodes on the board but add diodes to solenoids 3, 4, 6 and 7?

Never tried that. I suspect the flash flicker will still be present because it's the tieback to the 50V that is causing the noise.

8 months later
#20 81 days ago
Quoted from kbliznick:

modifying the board and coils will still allow you to put incandescents back in. This was just an error in placement by Williams.
Alternatively you can leave the diodes on the board and modify the board. If you look at the schematic you just need to move the unbanded end of the diode to the other side of the resistor that it connects to.

Someone found that I made a mistake with this second method for fixing this. Here is the correct information to do this as a board only fix and leave the coils under the pf the same.
_______________________________________________________________________________
Relooking at the schematic I see what I did wrong with suggesting this alternate method. Moving the diode to the other side of the resistor mimics the placement of the board mounted flyback diode on the 25V circuits. But as you found out that didn't work to stop the errant flashing. To actually mimic the placement of the adding the flyback diodes directly onto the A side coils at 3,4,6 and 7 you would have to cut and move the non banded legs of the D3, D4, D6 and D7 diodes to the non banded sides of diodes D33, D35, D39 and D41. This positions it so the flyback diode is isolated from the flasher circuits by the diodes that keep the A and C circuits apart.

This is more work than necessary to fix the issue, but does allow for a following owner or tech further down the line to not make the mistake of reverting a 3,4,6 or 7 coil with a diode for one without a diode

System 11 Flasher fix board only (resized).jpg

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