JD pinball drop targets on the fritz

[jspicher]

Hi Guys,

I've just purchased my first Pin, a Judge Dredd machine in pretty decent condition, but l'm having trouble with the drop targets. They continually drop and reset themselves over and over - thus making the game sort'a unplayable.

Here's a little video of the problem l've uploaded to youtube:


I've tried adjusting the tension on the springs for each target both very little tension and then very tight it made not difference. I then adjusted the "feet" that actually lift the targets after they reset (thinking maybe one of them wasn't being pushed high enough to to hooked, but that didn't seem to fix it either.

Any ideas on what this could be?

[studmuff]

It sounds like when you turn on the machine you are getgting an error on the DMD.  Does it tell you what it is?  if not, open the coin door and hit the far right service button.  It should tell you what the error is?  It could be a switch opto not working, could be the coil.  Remove the connector and reseat it on the 5-bank opto assembly board that controls the targets under the playfield.  Could be a wire off the connector or a cold solder joint on the header pins for the connector.  I don't own a judge dreed but I own Indiana jones.  It may not be the springs causing the problem.  Can you manually push on the bar that resets the targets to get them back up?  Do you still get an error?

Do you have a manual?

[smartbomb2084]

Put the game in 'Switch Edges' test and see if all the switches for spelling J-U-D-G-E are always closed. They are all located in switch column # 5, in order, along with Left and Right slingshots and Captive ball #2.

[smartbomb2084]

Looking at this video again I am really inclined to say that this is a switch problem.  Put the game in 'SOLENOID TEST' and check the operation of the drop target reset solenoid labeled 'DROP TARGETS' ( Sol # 5).  Be sure to CLOSE THE COIN DOOR or there will not be any 50 Volts to power the solenoids.

I heard the game in the video say "DON'T MOVE" which is an indication of the 'DRAIN SHEILD' ( Autofire that is ) activating. Is the ball in play being launched into the game and draining in this video or is the ball sitting idle in the shooter lane? If it is sitting idle I would say you definitely have a switch problem. Maybe leaky batteries took out U20 on the CPU board, column driver ULN2803A?

On a side note:   Don't run the game too much in this condition.  You are asking for trouble.

[studmuff]

Wondering if you ever got the problem fixed?

[jspicher]

Hi guys,

Quick update on the status of my JD machine.

On the bottom of the drop target bank there are three screws that allow you to adjust the reset arm up/down. I was able to adjust these screws and get the drop targets working normally again. Problem is, it was a short lived fix; after about 8 games it was back to the continual drop/reset loop as shown in the video.

After doing testing on the unit l found that the opto that registers when the "G" target is dropped wasn't recognizing the dropping target every time (jiggling the opto board would help get it to register). So l pulled the opto board out and gently cleaned between each of the optos with a q-tip and some rubbing alcohol, hoping it was just dirt build-up. This didn't seem to fix the problem either.

After doing a bit of research l found that the drop target opto board (factory original) is poorly designed and prone to failure; and a new opto board was made available some time ago. I believe that's the case with mine. I've ordered the new opto board, new springs, drop targets etc and l plan on rebuilding the drop target bank and hoping that fixes the issue. Thanks for everyone's help!

[jspicher]

Oh, I also picked up one of these with my order: http://www.pinballlife.com/index.php?p=product&id=1260&parent=0



Isn't that awesome?

[jspicher]

hi pinballjim,

Well if it's a cracked solder joint, then replacing the opto board would do the trick yes?
If so, I hope one of us is right!

Thanks,

[Q*Bert_OP]

Well if it's a cracked solder joint, then replacing the opto board would do the trick yes?

That's about as logical as replacing your car windshield because there's dirt on it. If you see any cracked solder joints, remove the old solder, then flow new solder.

[jspicher]

Howdy Q*bert >> That's assuming that the problem is a cracked solder joint. The stock board l've got in the machine is prone to failure. For starters l'm not much of a soldering guy, as a matter'o fact l don't even own a solder gun anymore. Secondly I've already ordered the new part (getting delivered today) and at this point l'd rather re-build the drop target bank. The springs are in a near comical condition, the clips holding the current board in place are shoty at best and the board itself (l think) has failed due to bad optos, cracked solder or whatever.

[jspicher]

What I don't understand is that you adjusted 3 screws and the problem temporarily went away... why aren't you looking at those three screws again?

 

Oh trust me l have, l've adjusted them one thread at a time and tested between each adjustment to get this damn thing to work properly. I've spent countless hours fooling around with this thing before breaking down and buying new parts to rebuild the DT bank. As mentioned in my previous post; if l were a soldering guy, had the equipment & know-how before l'd ordered the new parts l would have gave it a shot. But 1.) the parts were ordered before your suggestion, and 2.) l don't even know what l'm looking for regarding the cracked solder joint.

Thanks for your help,

[jspicher]

Hi Jim, Yep l've made sure the actual targets have plenty of clearance in front, back and on the sides and they're able to drop/raise freely within the slot provided on the playfield without being impeded in anyway by the playfield itself. This was one of the earliest assumptions l'd made regarding what could be causing the problem.

I know l've mentioned in an earlier post regarding this, but when they are jumping up and down like that if l press the opto board slightly back, or pull it forward the targets stop jumping, but as soon as l let go they begin jumping again. There really isn't anyway to secure the opto board in a single position it's just held on with a couple clips. I've even tried securing it in tight with rubber bands just for testing purposes.

[studmuff]

Howdy Q*bert >> That's assuming that the problem is a cracked solder joint. The stock board l've got in the machine is prone to failure. For starters l'm not much of a soldering guy, as a matter'o fact l don't even own a solder gun anymore. Secondly I've already ordered the new part (getting delivered today) and at this point l'd rather re-build the drop target bank. The springs are in a near comical condition, the clips holding the current board in place are shoty at best and the board itself (l think) has failed due to bad optos, cracked solder or whatever.

If you are going to own a pinball machine, you better become a solder guy real fast.  Cracked solder joints, wires desolder, replacing coils, switches, doides, resistors etc etc etc. 
As QBert said - if the prolem was a cracked solder joint, which it might be, tou can easily fix the problem by flowing some knew solder.  It would have saved you paying for a new board.  The other problem is you may install the board and have the same problem.  As Pinballjim just posted if it's not the board could be a problem with the coil hitting the targets up, the screws you adjusted, it could be the mechanism just dirty and needs to be cleaned.  The later has happened to me with drop targets.  Let us know if you get it working by replacing the board.

[jspicher]

Hi studmuff,

Thanks for your response and help throughout the thread.

If you are going to own a pinball machine, you better become a solder guy real fast.  Cracked solder joints, wires desolder, replacing coils, switches, doides, resistors etc etc etc.

Noted... l'll look into getting the gear.

As QBert said - if the prolem was a cracked solder joint, which it might be, tou can easily fix the problem by flowing some knew solder.  It would have saved you paying for a new board.

Maybe the case, l just don't know what l'm looking for. Here are two photos of both side of the old board that l removed tonight:
http://img204.imageshack.us/img204/5323/20100728204009.jpg
http://img293.imageshack.us/img293/7497/20100728204021.jpg

Do you see cracked solder joints? If so where, what do they look like?

The other problem is you may install the board and have the same problem.  As Pinballjim just posted if it's not the board could be a problem with the coil hitting the targets up, the screws you adjusted, it could be the mechanism just dirty and needs to be cleaned.  The later has happened to me with drop targets.  Let us know if you get it working by replacing the board.

Oh trust me, l've spent many many hours doing tests and trying to fix this w/out spending any money. I've taken the DT bank apart and cleaned it with q-tips and alcohol (so it's not dirt in the optos etc). I've adjusted the reset arm screws just about every possible combination. No joke l tested tested each thread to see if there was a sweet spot. I'm a cheap guy at heart, and l did everything l felt comfortable doing myself, including ordering parts and rebuilding the DT Bank.

[jspicher]

Just an update, l've finished rebuilding the DT Bank this evening and everything is working perfectly now.
I've posted photos of the old board, not sure what cracked solder joints look like (or if the naked eye can even see them), so please let me know!

Also thanks again to everyone who's pitched in and gave their suggestions and ideas on what the problem may have been, now l'm back to enjoying my new pinball machine! I'm already eyeballing another one; there's a guy here locally selling a Congo machine in fantastic condition.

Thanks again buds!

[studmuff]

Just an update, l've finished rebuilding the DT Bank this evening and everything is working perfectly now.
I've posted photos of the old board, not sure what cracked solder joints look like (or if the naked eye can even see them), so please let me know!

Also thanks again to everyone who's pitched in and gave their suggestions and ideas on what the problem may have been, now l'm back to enjoying my new pinball machine! I'm already eyeballing another one; there's a guy here locally selling a Congo machine in fantastic condition.

Thanks again buds!

Glad you got it working. 
I don't see any pics, where did you post them.  Most of the time you can see the crack joints but not always.  I had some flaky bulbs on my GREED lights on my Addams Family.  I checked the diodes with a DMM and they were normal.  I could see a cracked joint on one of my pins and reflowed the solder to all of the pins and it now works perfectly.  It may not have been the solder joints though and could have been the optos.  It's always hard to tell if youur not there looking at the machine and the parts.  Have fun with the game.

[jspicher]

Just an update, l've finished rebuilding the DT Bank this evening and everything is working perfectly now.
I've posted photos of the old board, not sure what cracked solder joints look like (or if the naked eye can even see them), so please let me know!

Also thanks again to everyone who's pitched in and gave their suggestions and ideas on what the problem may have been, now l'm back to enjoying my new pinball machine! I'm already eyeballing another one; there's a guy here locally selling a Congo machine in fantastic condition.

Thanks again buds!

Glad you got it working. 
I don't see any pics, where did you post them.  Most of the time you can see the crack joints but not always.  I had some flaky bulbs on my GREED lights on my Addams Family.  I checked the diodes with a DMM and they were normal.  I could see a cracked joint on one of my pins and reflowed the solder to all of the pins and it now works perfectly.  It may not have been the solder joints though and could have been the optos.  It's always hard to tell if youur not there looking at the machine and the parts.  Have fun with the game.

I was having trouble uploading photos from my phone last night, here they are:
http://img204.imageshack.us/img204/5323/20100728204009.jpg
http://img293.imageshack.us/img293/7497/20100728204021.jpg