Skateball Drop Targets (TECH)

[tomdotcom]

Hey guys I'm having an issue with my Bally Skateball Drop targets. Whenever the drops reset during gameplay or at the start of a new ball the far left drop target gets raised to high. It happens a good 90 percent of the time. It gets stuck up and usually won't come down, even when the drops reset on a new ball.

I took a good look inside at the springs and connecting plates/rods. Everything "looks" ok.

Need some advice as what I should be doing to fix this? Someone must have run into this problem before? The only way to make it go back down is to twist the drop target a bit from the top so it drops back down into the normal raised position.

See here for pics of what I'm talking about:

http://www.flickr.com/photos/tomdotcom88/sets/72157622865105411/

[Extra Ball]

It looks to me that only one target is raising high enough, because you cannot see the bottom part of the other two's skater artwork:



Have you ruled-out the white rubber causing an issue? Other than that an expert will help here I am sure.

[Strangeways]

Remove the target assemby and check to see if the problem persists. I think it is the plate that guides the metal tab that actuates the "drop" switch. Sometimes it is a build up of lubricant etc..

Best way to fix the issue is to clean and rebuild.

[tomdotcom]

Thanks for the advice Strangeways..

I'm also going to replace the spring as it may not be holding it properly. Going to check if it's binding on the hole where it comes out of the playfield.

Whatever it is, it's very slight, I looked hard and long and from underneath nothing seems different then the other targets. I guess I may have to pull it apart and clean it and make sure it's all aligned properly..

Was hoping for a quick fix of course :P

[tomdotcom]

I wonder if maybe the coil stop could be worn down? Maybe it's pushing the targets to high cause of that. And that one target just happens to jam because of that...

[ddstoys]

I wonder if maybe the coil stop could be worn down? Maybe it's pushing the targets to high cause of that. And that one target just happens to jam because of that...

If it was the coil stop all targets would be lifting to high

[tomdotcom]

Ok I pulled it all apart and swapped a target and took a REALLY good look at everything, here's my findings below:

There are slots in the back of the drop target assembly. The metal
plates that attach to the bottom of the drop targets ride in these
slots. What happens is that when the coil kicks all the drop targets
up, they go up higher then they need to (same as all the machine drop
targets) and that metal plate ends up shifting a bit to the side and
comes out of the slot and jams off center. So that's why the target
won't come down. That metal plate has ridden out of the slot and is
jammed. If you reach underneath and just shift that plate over, it
falls right into place.

Maybe those plates are just worn down a hair too much?

The targets seemed fine at a quick glance when I pulled them out? You
guys think that if just replace those 3 targets then that metal plate
won't shift anymore?

A guy on RGP mentioned that the targets may be flexing, causing that metal plate to shift..

[Strangeways]

The LARGE plate behind the targets with the slots in them might be warped.

The metal "arms" on each target may be warn - a simple test would be to move the offending target and arm to another slot.

I had this exact issue on my Space Invaders after I installed new targets. I ended up removing the large plate behind the targets and refitting. It must have been slightly out of alignment.

[tomdotcom]

I think I figured out the offending piece. It's the bottom metal
assembly with the slots in it. It seems like the metal plates that
attach to the drop targets are not hitting the slots right.They are
supposed to hit against the bottom of the slot which causes the drop
targets to top out at that point. But they don't quite hit the slots
right, because the slots are worn they end up clearing the slots
altogether.

 The slots seem a bit worn so the drop targets end up going higher
then they should, causing the metal plate to jam in the back slot.

I tested the other drop assemblies in the machine and when you push
the drops all the way up the metal plate that attaches to the drop
hits the bottom of the slot on the bottom assembly and that stops the
metal plate attached to the drop assembly.

I also took apart the coil and the coil stop and coil plunger seem
fine. I pushed the rod all the way in and compared it to the other
drop assemblies and it looks like it goes up the exact same amount.

So either those slots are a bit worn. Or the coil stop or coil plunger
are worn so the coil pushes the targets to high.

When you push up the drop targets, ALL of the metal attaching rods go
up to far. That is a BIG clue. So sometimes other targets are getting
stuck as well. Not just one...

I took some more pics here:
http://www.flickr.com/photos/tomdotcom88/sets/72157622995642512/

[tomdotcom]

Here's a couple other mickeymouse fixes that I just noticed while I
was under there:

http://farm3.static.flickr.com/2752/4183570056_3818714a16_b.jpg

http://farm3.static.flickr.com/2770/4183564164_9284a990e3_b.jpg

[tomdotcom]

I swapped out the coil plunger and coil stop from a working bank and that didn't help. Same problem. So I can rule out that at least.

The targets and the link plates that attach to the bottom of the drop targets definately go up to high or something isn't aligned right. The link plates go up to high and come out of the slots at the back, causing the target to jam...

[tomdotcom]

OK I seem to have gotten it fixed for now. I just didn't tighten the bottom plate on as hard. I was thinking if maybe I put a bit weaker coil on that assembly that it wouldn't happen anymore. Right now that coil is kicking up the targets harder then it really needs to, I think if I replaced it with a weaker coil it wouldn't cause the jamming anymore?

I played a good 30 games or so after I put that bottom plate back on and so far so good, but I think the a bit weaker coil may fix the problem for good...