(Topic ID: 250336)

Ghost switch hit on DM


By dri

1 year ago



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  • 5 posts
  • 2 Pinsiders participating
  • Latest reply 1 year ago by dri
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#1 1 year ago

I'm chasing a credit dot on my DM. So far no luck. This state is at the beginning of a ball with the ball still in the shooter lane. You flip the left flipper that in turn energizes the right ramp diverter. In 75% of the cases it triggers the right ramp exit, which scores 250k and also lights Quick Freeze. If it happens on the next flip/diverter energizing it will give you a freeze.

Switches involved works just fine, I've changed diodes on the ramp exit and shooter lane (same row). Last time I had an issue like this on TZ I had to brute force it by changing every diode in the row and column of the affected switch. Is there a smarter way to find the culprit?

#3 1 year ago
Quoted from dri:

Switches involved works just fine, I've changed diodes on the ramp exit and shooter lane (same row). Last time I had an issue like this on TZ I had to brute force it by changing every diode in the row and column of the affected switch.

This will only work 66.6% of the time as there is a 1 in 3 chance the problem is NOT in the same row or column as the phantom closure.

This type problem is one of the trickiest things to troubleshoot, having an oscilloscope does help with this one as there are specific timings involved, but the problem requires activation of 3 switches simultaneously to even be seen.

Take a look at this post https://pinside.com/pinball/forum/topic/gun-broken-and-suddenly-right-ramp-slam-tilt#post-4320824, its not for your specific machine but the principles still apply.

Quoted from dri:

I'm chasing a credit dot on my DM.

Not sure what the credit dot is for since you didnt say, but a switch matrix phantom closure issue will not typically cause this as ALL switches will function normally.

#4 1 year ago
Quoted from Pin_Guy:

Take a look at this post

Thanks for the inputs and the additional reading. I'll see if I can make such "box" on my switch matrix. There's definitely closed switches at play here.

Quoted from Pin_Guy:

Not sure what the credit dot is for since you didnt say, but a switch matrix phantom closure issue will not typically cause this as ALL switches will function normally.

Oh, the credit dot reports the diverter is stuck closed as the ramp exit switch is not supposed to get hits when it's open.

1 month later
#5 1 year ago

For Internet karma and a perfect playing DM. I replaced the resistor and diode on the optoboard hosting switch #67 and the ghost hits vanished.

Screen Shot 2019-09-29 at 11.26.35 AM (resized).png

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