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(Topic ID: 212252)

DE Simpsons - Multiple Coils/Switches Activating


By ddunlow

2 years ago



Topic Stats

  • 9 posts
  • 4 Pinsiders participating
  • Latest reply 2 years ago by terryb
  • Topic is favorited by 2 Pinsiders

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#1 2 years ago

I need some help finding and fixing this problem.

The game starts and plays normally at first. The issue seems to start when the ball goes into the right lock (the one with the vertical kick). At this point everything seems to go crazy. The right flipper fires the right pop bumper and other switches. The left flipper fires the center pop bumper and other switches. I say other switches because this all happens at once and I can't tell what trigger what. When this starts, the multiple ball starts, the "shoot the ramp" starts, and Millions start. The ramp exit switch also is activated repeatedly while hitting the flippers. Once the ball drains, the weirdness stops. It will, however, start again.

My kids continued to play the machine while it was acting this way. Eventually, the center bumper locked on. I pulled the board out and tested the transistors. Found and replaced one damaged transistor. This fixed the locked-on bumper, but the strangeness continues with multiple thing happening at once.

Can this all be caused by a bad diode? I have read this can cause strange gameplay.

#2 2 years ago

It sounds like the switch for the ball lock/VUK is not working and the game goes into ball search mode resulting in random coils firing.

#3 2 years ago

The VUK switch works normally. The ball kicks out, but then then thats when the fun starts. When you press the right flipper, several switches activate, including the right pop bumper and I believe the ramp exit switch. But, its not only the right flipper. Pressing the left flipper triggers the center bumper as well as other switches.

The kids loved playing the machine this way because when the problem starts, it triggers multi ball and "millions." They played it this way until the center pop bumper was stuck on and nearly burned. I caught it before that, thankfully. I found a replaced a bad transistor. That fixed the bumper, but the original problem is still there.

Thanks for your reply.

#4 2 years ago

I watched the kids playing the machine to figure out what was happening. I have found the one switch that starts the problem. It is switch number 45. Its a drop target. When this target drops, multiple switches activate. This problem is NOT contained to one row or column. While the drop target is down, the left flipper triggers the center bumper. The right flipper triggers the right bumper. All these problems go away instantly once the drop target is reset. What can cause this problem?

I have checked the diode on the switch. It was good.

#5 2 years ago

Bad diode?

#6 2 years ago
Quoted from ddunlow:

I watched the kids playing the machine to figure out what was happening. I have found the one switch that starts the problem. It is switch number 45. Its a drop target. When this target drops, multiple switches activate. This problem is NOT contained to one row or column. While the drop target is down, the left flipper triggers the center bumper. The right flipper triggers the right bumper. All these problems go away instantly once the drop target is reset. What can cause this problem?

Reversed or shorted diode or diode lead touching ground or one of the leads on the switch.

Get the switch matrix and circle the drop target, the center bumper and the left flipper. That will give you three corners of a rectangle. The problem will be with one of those switches, most likely the fourth corner of the rectangle.

#7 2 years ago

After dinner, I'm going to check the grounds on the switches. Also, when I complete the rectangle in the switch matrix, it's the #3 trough. I check that out too. I'll check it's diode.

Thanks for the input!!

#8 2 years ago

I found a reversed diode on the trough switch. I am amazed how you guys pointed right to a problem... BUT, after fixing it, the problem continues. Everything works normally, until that drop target is hit. While it is down, multiple row act as one. Once the drop target is returned to the up position, everything goes back to normal. Using the switch test, activating the the drop target does not do anything out of the ordinary.

I have check the wiring around the drop target to see if any wires touch each other. I will continue to look for something that can cause contact when the switch is down. Is there something else I can be looking for that can cause this? That diode must have been like that for several years!

Thanks!!

#9 2 years ago
Quoted from ddunlow:

While it is down, multiple row act as one.

Can you explain this in more detail? Please use switch numbers when describing.

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