Lethal Weapon 3 pin pickup! (DMD issue)

shardian

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Picked up my new Lethal Weapon pin this evening. After checking a few things, making sure the right number of balls, etc. The game plays 100% except for the DMD.

The DMD stays 100% lit at all times. According to pinrepair, that means the 8A fuse is bad, or the rectifier is bad, or the cap is bad...kind of. The pinrepair guide specifically says the '100% on' problem is only for the tiny DE DMD.

What is causing the full on DMD?

BTW, fuse tests good in and out of circuit.
 
While playing a game, I was nudging and noticed life on the DMD, and of course a lightbulb went off!

I pulled out the DMD, and sure enough a connector was off. Plugged it in, and the DMD worked, but there is one column of pixels still 100% lit. I'll try reseating all the connectors on the DMD again later.

BTW, I'll have pics up in about an hour.
 
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Pics as promised. As you can see, the cabinet has some wear. The metal pieces need painted. The playfield has no wear at all. A simple cleaning will have it mint. There is one broken plastic. The left kickout hole, and the right slingshot don't work. Kickout is just super weak, sling does nothing. Haven't run tests yet. The skill shot targets need replaced too I suppose. Other than that, the game works perfectly. Flippers and all other coils are strong.

I can't believe I got this game working so easily. I believed the guy when he said it had issues. He even bought a brand new MPU... just goes to show a little troubleshooting goes a long way when buying $200 parts!

Oh, and one more thing: playing this pin with the glass off causes hearing loss, we are pretty sure! I need to get the kickout coil fixed quick so I can put the glass back on.
 

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Nice grab! And nice fix! the LW3 I recently picked up had a very similar issue with the DMD not working at all.. Loose connections on the board took care of it. the display was a 100% working though, so no idea on the single line being lit.


Oh, and replace the battery if its original!! Caught mine jus as it started leaking thankfully no damage.
 
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Pics as promised. As you can see, the cabinet has some wear. The metal pieces need painted. The playfield has no wear at all. A simple cleaning will have it mint.

Go for more than a "simple cleaning" ... there are lots of hidden dirty areas that will just track dirt all over your game again. Take as much of the topside stuff off as you can, and clean every nook and crannie. Clean the ball trough, the kickouts...basically anywhere the ball's going to travel. Get new balls, too! You don't wanna have dirty balls, Sharidan :)

There is one broken plastic. The left kickout hole, and the right slingshot don't work. Kickout is just super weak

First make sure the right coil is on there. Then - check out the coil sleeve and plunger. Are they dirty or sticky? Some people lube these parts when they shouldn't...that just gunks 'em up. Sometimes a weak coil can be solved by just cleaning the parts up and adding a fresh new sleeve.


, sling does nothing. Haven't run tests yet.

Check the wires/solder on the coil...could be a loose diode! I've had lots of flakey pinball parts due to cold solder or loose diodes. Worse case scenario it's an associated transistor...relatively easy fix.


The skill shot targets need replaced too I suppose.

Are they just not registering shots well enough? You might just want to remove them, and bend/clean the leaf switches. That'll get the sensitivity back. Or - again, could be a loose diode!
 
I'll eventually tear it down and clean it thoroughly, but I want to play it for a few months first. That will give me something to renew interest later.

Slingshot was a broken wire - it works fine now. Kickout had a cold solder joint, but it did not fix it. The mechanism seems to work perfectly. I can activate it with very little effort. I can see it barely nudge the ball when it tries to kick. I'll verify the coil type later on. Appears to be right compared to other coils though. There is no diode across the lugs, but I haven't learned enough to know if it is necessary on this game.

The targets are pretty busted up. They are the type that have a square plastic frame around the metal target. 2 work, two don't. I'll tear them down and see if I can at least get them functional.
 
Kickout had a cold solder joint, but it did not fix it. The mechanism seems to work perfectly. I can activate it with very little effort. I can see it barely nudge the ball when it tries to kick. I'll verify the coil type later on. Appears to be right compared to other coils though. There is no diode across the lugs, but I haven't learned enough to know if it is necessary on this game.

The targets are pretty busted up. They are the type that have a square plastic frame around the metal target. 2 work, two don't. I'll tear them down and see if I can at least get them functional.

Yes it does need a diode on the coil. Since it is missing you probably have fried the driver transistor on the CPU Board, check for a burned out transistor.

And those skill-shot targets take a beating. Might be easier to replace them. Mine register but look awful, they will be replaced when I get to shopping mine out.

Mike
 
Yes it does need a diode on the coil. Since it is missing you probably have fried the driver transistor on the CPU Board, check for a burned out transistor.

And those skill-shot targets take a beating. Might be easier to replace them. Mine register but look awful, they will be replaced when I get to shopping mine out.

Mike

I haven't seen a diode on any coil yet! I have seen diodes on lamps though.
 
Yeah there are diodes on every coil. They were all just hidden on the opposite side of the coil than I was looking.

I still can't figure out the left kickout hole. The coil tries to fire in-game and in test mode, but the plunger just moves about 1/8". I replaced the sleeve, and sanded/polished the end of the plunger. There is nothing to adjust in the mechanism, but it moves just as freely as any of the other kickouts in the machine. If I press slightly on the armature then hit the test button, the coil will fire. If I let back up off though, it is back to barely moving.

Anyone have any ideas??? There simply is nothing providing the resistance necessary to stop the coil from firing.
 
Hey,

Hey,
Hey it might be a driver and the pre driver for the coil. Make sure you put that diode on the right way. Stripe to the big wire. Let me tell you about LW3....This is a funny set up. Check the make of your DMD. If it's a Babcock then this is the trouble you might have. Because of the way the Babcock is set up with the power supply that you have. It can only be replaced by a Babcock. If you try to get a new power supply for it like a rotten dog power supply your old babcock will not work. You will have to have a new display to work with a rotten dog power supply!! You might be having a problem with out-gassing on your display. If that is the case GET A NEW DISPLAY!!! Could be the display roms on the back of the DMD dot matrix board.Some times if you pull them out and re set them it helps. When a display starts to go out a bunch of the time it will take the power supply out with it. When I figured out all of my problems with the LW3 game that I had it makes me laugh. It was like a three year project. Take my word for it. Get the best power supply that you can. If yours is bad fix it or send it to the coin op cauldron. Check to make sure you don't have any burn on the Molex plugs going into your power supply. Or just get a new rotten dog power supply. If you do that then buy yourself a NEW :) DMD from Terry at pinballlife.com. I think he has babcock or vishay DMDs. He is the best price around and he ships out Fast,Fast,Fast. And when he sends a DMD it is packed like FORT KNOX . It might be simple fix with the display, but you have to get it working on a LW3 because it helps the game a bunch. It also has that cool add for tales from the Crypt Pinball Machine. :) And you need it for Fighting by pushing your flipper buttons. When you get a new power supply and a DMD it's like a new game. Good luck! When I was finished I played my LW3 all the time. I sold it but only because I have a Data East JP. Cool game...Ok OK OK OK OK
 
The coil is not shorted. Even if it was, the last problem I would be having is a weak coil - it would be locked on or really strong.

And I agree, the Tales From the Crypt Ad is AWESOME! We were sitting at the new pub booth in the gameroom today chatting, when that ad came on. We all turned around to watch it.
 
I kept noticing in the IPDB comments, that people think the 'okay okay okay' thing was annoying. After playing all weekend, I kept wondering why everyone was complaining. I re-read some of the comments today, and it makes sense now. There is a tube of roms in the coin area of the game. One of the commenters said that alot of the "okay's" go away with a rom revision update. So, I apparently have updated roms. I might here the 'okayokayokay' 2-3 times a game.
 
I had an odd issue pop up yesterday after troubleshooting the kickout hole for a while. Normally, the flipper and gun ciols disable during video modes. Well yesterday evening they stayed active during the vid modes. Anyone have a clue what might be the issue?
 
I kept noticing in the IPDB comments, that people think the 'okay okay okay' thing was annoying. After playing all weekend, I kept wondering why everyone was complaining. I re-read some of the comments today, and it makes sense now. There is a tube of roms in the coin area of the game. One of the commenters said that alot of the "okay's" go away with a rom revision update. So, I apparently have updated roms. I might here the 'okayokayokay' 2-3 times a game.


I was wondering about that! I hear the okay-okay thing every now and again but not often to drive me nuttier.

I'll have to check what rom version I have, curious now!

And for your flippers staying on.. Sounds like it might be a relay staying closed when it shouldn't.
 
Okay, the left saucer is still giving me fits! I have taken apart the whole thing, sanded down the plunger tip, replaced the perfectly fine coil cleeve, cleaned it, etc. The thing moved butter smooth - better than the other perfectly working kickouts on the game. Still, the damn thing just moves a small amount when fired. Before I cleaned everything, I could lightly press on the mechanism to get it past the 'catch point', and it would fire. It seemed weak though.

Everyone tells me that this has to be a mechanical issue, but I'm telling you - the mechanism is perfectly fine. Tonight, I will replace the diode (even though that probably isn't the problem. Another thing I noticed after reading, is that pitting on the L/R relay can lead to low voltage at coils. I need to test voltage at the coil tonight too. Technically this should effect all coils on the L side of the relay. Every other coil in the game is strong.
I might also just drop in the extra MPU I have.

I'm at a total loss as to why this coil is not working.
 
If you believe that the left saucer is mechanically OK, then you might want to try a different driver for it. Desolder the wire to the coil from the CPU board (I believe that this will be the small one), and also desolder one from a working saucer. Now jumper the working saucer's wire over to the left saucer and test it. Be careful that you do not short out anything with the loose wires (I would cover them with electrical tape).
I believe that you will find that it works fine and that the driver transistor, or pre-driver transistor is bad for that coil.
 
I should be able to just alligator clip the signal ground lug from the other saucer to this saucer, right? They share the same power wire.
 
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