(Topic ID: 127177)

Yet another Grand Prix Tech question.


By Arcade

5 years ago



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  • 16 posts
  • 5 Pinsiders participating
  • Latest reply 5 years ago by Arcade
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Williams_1976_Grand_Prix_Manual.pdf (page 33 of 36).png
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IMG_0754.JPG

#1 5 years ago

Got another crazy little problem with my EM Grand Prix.
This one is not a big deal but it still bugs me.

The very top outhole is supposed to score 5000 points and advance the bonus 2 steps.
This works perfectly as long as the advance left bonus light is lit up top by the hole.
But if advance right bonus is lit up top and the ball goes in the outhole it will always score 5500 points.
Crazy right?
We have eliminated the score cam motor in the bottom of the cabinet and the point score contacts in the back of the head.
In the photo below you can see that under the playfield there are two relays that say left advance relay and right advance relay.
The left one works perfectly and only scores 5,000 points when activated.
The right one causes the 500 point relay that is also mounted on the underside of the playfield to energize and makes the game score 5,500 points instead of 5000.
Kind of at loss as to what is causing this odd problem.
Photo below of the two relays in question under the playfield.

IMG_0754.JPG
#2 5 years ago

Afternoon bump for anyone taking a break from the Khan or Kai thread, things you irrationally hate thread or how bad the hand and arm art is on KISS thread.

#3 5 years ago

To clarify, you are just trying to figure out why you are getting the extra 500 points? Are the drop targets scoring 500 points? If so, based on the schematic I would check the following switches:
1. All normally open switches on the 500 point relay
2. All normally open switches on the target relay
3. All switch on Cam 3 of the score motor

#4 5 years ago
Quoted from bonzo71:

To clarify, you are just trying to figure out why you are getting the extra 500 points? Are the drop targets scoring 500 points? If so, based on the schematic I would check the following switches:
1. All normally open switches on the 500 point relay
2. All normally open switches on the target relay
3. All switch on Cam 3 of the score motor

Yes. The only thing that scores wrong on the game is the top hole when the right side bonus advance light is lit.
Everything else scores perfectly.
And if the left side bonus advance is lit, the top hole scores 5,000 just like it is supposed to.
It is a very strange problem

#5 5 years ago

The only RE that will pulse the 100 point reels 5 times via the 100 point RE is the 500 Point RE. If it is any other SW holding the 100 point RE in , then it would pulse once and lock.

There are only 3 SW that can energise the 500 point RE, none of which should be affected by the R.Bonus or R.Advance REs.

Look at the 500 point RE and close the top eject hole while the R Bonus lit, does this RE energise?

help.jpg

#6 5 years ago

have you double checked the gapping on all 500 point leaf switches, wonder if you just getting a hit from vibration. Also, when it switches from right to left there is relay that handles that shifting (on my game it has a little buzz when active to one side (right I think), I don't see you making any comment about that relay (I don't have the schematic in front of me), but I would also look at what is passing through that or near that (e.g. relative to a gap issue).

#7 5 years ago
Quoted from Chrisbee:

The only RE that will pulse the 100 point reels 5 times via the 100 point RE is the 500 Point RE.

I certainly may be wrong, but since the 1,000 point relay is pulsing 5 times, this 500 points may not be coming through the 500 point relay, but as a result of the 5 pulse to the 1,000 point relay triggering through to the 100 point relay via some path independent of the 500 point relay.

I certainly may be wrong on this, but the spinners go through the right and left bonus units, just like the top eject does, so if a spinner is stuck closed when in resting position, I believe that would result in the 500 points as well.

Williams_1976_Grand_Prix_Manual.pdf (page 33 of 36).png

#8 5 years ago

Thanks this is all great info.
I do realize it makes no sense but as long as the left advance light is lit the game will score prefect all the time.
If the right side is lit both the 100 point reel and the 1000 point real will pulse together 5 times.
I will look into everything above tonight.

#9 5 years ago
Quoted from rosh:

so if a spinner is stuck closed when in resting position,

You should also be checking the switch on the right spinner relay vs the spinner itself. I have found that if the spinner itself is an 'closed' state other aspects of the game will not behave correctly.

#10 5 years ago
Quoted from rosh:

You should also be checking the switch on the right spinner relay vs the spinner itself. I have found that if the spinner itself is an 'closed' state other aspects of the game will not behave correctly.

Thats a good idea rosh. I own the game with him and that right spinner has stuck closed before. Also the 500 point relay is activating when the problem occurs. It does not activate when advance left bonus is lit but does when the right is. The switch controlling the left and right is the match switch in the back box. No scoring comes from that stepper though.

#11 5 years ago
Quoted from KingNine:

500 point relay is activating

If that is activating, then it is probably not the spinner, since that is a 100 point pulse. Certainly makes sense though to take a closer look at the 'change' relay, since a bunch of things run through that.

How are you advancing the match coil to switch from left to right for your testing?

#12 5 years ago
Quoted from rosh:

If that is activating, then it is probably not the spinner, since that is a 100 point pulse. Certainly makes sense though to take a closer look at the 'change' relay, since a bunch of things run through that.
How are you advancing the match coil to switch from left to right for your testing?

Yes The 500 point relay pulls in.
We are advancing the match coil by hitting the two slings at the top on either side of the outhole.

#13 5 years ago
Quoted from Arcade:

We are advancing the match coil by hitting the two slings at the top on either side of the outhole.

I wonder if those are considered the 'stand-up' targets that feed the 500 point relay as Chrisbee pointed out, if so, I would check carefully there for a stuck switch, etc. hmm, I may have to go take a look at that tonight.

#14 5 years ago

Just figured it out. On the mid right of the playfield is a sling switch that scores 500 points. Yep. It had a very tight rubber that was holding it closed.
Homer Simpson Doh moment.

#15 5 years ago

Odd that it only happened when the right bonus was lit. But its fixed and that is what counts.

#16 5 years ago
Quoted from Arcade:

Just figured it out. On the mid right of the playfield is a sling switch that scores 500 points. Yep. It had a very tight rubber that was holding it closed.
Homer Simpson Doh moment.

Quoted from Chrisbee:

Odd that it only happened when the right bonus was lit. But its fixed and that is what counts.

Agreed.
It was really crazy because before we figured out it was a left/Right bonus advance issue, we would think we had it fixed just because it had the left bonus advance lit. Then when the ball would go in the hole with the right bonus advance lit the machine would appear to be broken again.
Made the issue twice as hard to follow as it should have been.
I also don't understand with the 500 point switch stuck closed why the machine was not constantly scoring 500 points all day long. That sure would have made it easier to diagnose. lol

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