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Congo - erratic post beside left ramp (pwned!)

superjackpot

Active Member
Nov 19, 2012
342
45
28
Mississauga, ON
During TOPL last night this problem was spotted by Adam. Fortunately, this game was not in tournament play rotation.

I typically won't post looking for help until I've tried to first fix a problem myself but given the unique symptoms of this, I'm thinking someone may recall seeing this one.

During Amy mode, started by completing the rollovers, the ball is ejected from the upper saucer back down the left orbit and is supposed to be stopped by the metal post located left of the left ramp. It is supposed to rise up from the PF to catch and hold your ball momentarily and then release it allowing you to hit the ball back into the Amy saucer with your upper left flipper. This cycle repeats a few times assuming you are able to get the ball back to the saucer in a timely manner.

What happens is at the start of Amy mode the post rises up just for a second around the time the ball is ejected from the saucer but drops just before the ball first arrives. The post does the same thing the next time the ball is returned to the saucer and ejected (during the mode). The strange thing is that for Grey mode the post is working 100% and will rise from the PF and hold the ball in place until the lower pf mode is completed. So, obviously the coil hold works.

Anyone seen this before? I'm suspecting a flakey diode related to the Amy saucer eject coil, perhaps switch, but have not got around to troubleshooting this yet. It will be the first thing I change when I do.
 

Vengeance

Well-Known Member
Nov 14, 2012
1,990
139
63
Keswick, ON
Re: Congo - erractic post beside left ramp

Hey Barry

Thought I mentioned this last night, I'm pretty sure it's the switch right beside the post.

When the post was going up and done it looked like the switch was moving as well, which would tell the post the ball was already on the switch, hence why the coil dropped back down.

Adjust the switch so that when the coil energizes it doesn't move and it should fix the issue.
 

superjackpot

Active Member
Nov 19, 2012
342
45
28
Mississauga, ON
Re: Congo - erractic post beside left ramp (Solved)

Thanks Adam, it was the left orbit switch.

The switch was mounted firmly but the arm had enough side to side movement allowing it to occasionally bind on the edge of the slotted opening in the PF. Turns out one of the nibs on the switch body was worn. I removed the switch arm, squeezed the arm tabs together a bit (not too much so as to bind) and replaced the arm using the back up nibs and reinstalled. The switch arm now moves up and down squarely in the centre of the slot without binding.
 

superjackpot

Active Member
Nov 19, 2012
342
45
28
Mississauga, ON
Re: Congo - erractic post beside left ramp (Solved)

Not so fast!

I was playing GREY mode in the lower PF... needed one more letter and nudged the machine to get the ball to the edge of the grey's hand/flipper which caused the post holding my ball on the upper PF to drop resulting in an impromptu 'multiball'. After that, I could no longer start grey mode even though I completed all the letters again. The post would not hold the ball...

There's more to this - still investigating.
 

Menace

Well-Known Member
Staff member
Nov 14, 2012
2,440
255
83
Santiago de Aurora
Re: Congo - erractic post beside left ramp (still resolving)

I'd replace the switch with a new one. Clearly that switch is tied directly to the behavior of that up-post.

D
 

mwong168

Administrator
Staff member
Nov 14, 2012
6,681
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Toronto
Re: Congo - erractic post beside left ramp (still resolving)

I'm not surprised that it could be the switch because WPC95 titles are known to have switch issues. If you need some switch bodies I've got some on hand you can borrow for now till your next order.
 

superjackpot

Active Member
Nov 19, 2012
342
45
28
Mississauga, ON
Re: Congo - erractic post beside left ramp (still resolving)

Menace said:
I'd replace the switch with a new one. Clearly that switch is tied directly to the behavior of that up-post.

Makes perfect sense and I will take this approach.

mwong168 said:
I'm not surprised that it could be the switch because WPC95 titles are known to have switch issues. If you need some switch bodies I've got some on hand you can borrow for now till your next order.

Recently I've been raping my folded TZ for such parts, and a brand new switch is in order. I do need to place an order anyway, so will add a few switches to the list.


Thanks guys.
 

superjackpot

Active Member
Nov 19, 2012
342
45
28
Mississauga, ON
It's been a while since I had time to revisit this issue but I'm happy to say I solved it.

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The initial fix to realign the switch inside the slot opening corrected the non working AMY mode, it may have been binding. But then I starting experiencing premature ball release whenever earning GRAY and playing the lower playfield :mrgreen: . At first the post would drop while I was on the lower PF, causing the upper PF flippers to start working with its ball back in play, as the lower PF mode continued. Not good. Changing the post switch to a brand new Cherry DB3 made no difference here. I suspected a faulty shooting lane switch since I recalled during game play it would very rarely not make. Changing that from a DA3 to a DB3 made no difference either. I heard WMS DA3s can be intermittent.

Then the symptoms changed. Making GRAY would raise the post, but the lower PF did not engage, upper PF flippers were still active followed by the post dropping about three seconds later. Switch test showed the (new) switch was fine and nothing else would incidentally trigger it. :?

I'd start another game to do more troubleshooting whereby I got a first time ever test report 'Check Upper Flipper Post'. The post was going up and down, just not staying up when it's supposed to. What did this message mean? The post (coil) tested fine. This just became a distraction.

Turns out, even though the switch arm itself was properly exposed above the PF, its point of disengagement was very, very close to resting position of the ball when held up by the post. This would cause either:

--> the switch to disengage after the resting ball was moved a bit likely due to vibrations when playing the lower PF = lower PF mode continues, upper PF ball released and becomes active, or
--->the switch to be disengaged by the time the ball came to rest at the post = lower PF never starts, upper PF remains active, ball releases seconds later.

Realigning/replacing the switch created the sensitive threshold above even though I never messed with bend in the arm. Flattening the triangular bend in the portion of the switch arm above the PF corrected the problem. The switch is now held down properly in all possible ball resting positions.
 

blackbeard

New Member
Jan 14, 2014
4
0
0
Buffalo
Hey, I've been having the same issue.

Each time I hit a letter in GREY, the gorilla moves in the lower pf. However, once completely spelled, the post goes up, the ball is trapped, but the lower pf doesn't activate.

I have been getting the Check Upper Flipper Post error too.

Everything works in diagnostics.

I"m hoping your solution fixes it. It looks like you just widened (flattened-out) the switch arm so that when the ball is trapped by the post the switch is triggered down (engaged), which should engage the lower pf.

Does this sound correct to you?
 

blackbeard

New Member
Jan 14, 2014
4
0
0
Buffalo
Yep, sure enough, that upper loop switch #45 was the culprit. The ball, in it's resting position against the popped post, didn't engage the switch, therefore NOT activating lower pf.

After about 2 hours (seriously) of taking the switch out, adjusting, tightening back up screws, etc, I think it's adjusted just right. What a PITA that one is.

What I ended up doing was going onto Marco Specialties' site, finding the switch there, and basically bending and crimping my switch to match the one in Marco's picture. Worked great.

Another general switch issue I noticed is that one must pay attention to the two tiny screws on the side of the switch. If they're too tight, the actuater arm won't move freely.


Anyway, it's fixed. I may order a new one to have on hand at some point in the future. That arm has to be bent JUST right or the ball won't go up the loop OR when it comes down, it won't activate it.
 

superjackpot

Active Member
Nov 19, 2012
342
45
28
Mississauga, ON
arm has to be bent JUST right or the ball won't go up the loop OR when it comes down, it won't activate it

Yup that's exactly it. It's a two way switch and the bend has to work for all three purposes: left orbit shots going north (at full speed!) and south, and when the ball is resting against the post. Substantially flattening the switch arm above the PF is what I found I had to do. The typical upside down v-shape bend in the switch arm ending up being much flatter and more parallel to the PF. Plus I changed the angle of the arm near the microswitch button. No room for error now.

After more than a year of perfect behaviour I'm guessing heavy left orbit shots probably pushed the switch arm into a more vertical position or moved the switch just so.
 

blackbeard

New Member
Jan 14, 2014
4
0
0
Buffalo
Exactly.

I'm just hoping my bend job stays good. I was honestly working on that thing for about 2 hours last night.

I can't find that exact switch either by part number. Marco has a very similar one, but not the same. I may email Pinball Resource and ask..

Thanks for your post btw. I was a bit stumped with this one.