(Topic ID: 199476)

Judge Dredd planet and crane wierdness


By CaptianTim

3 years ago



Topic Stats

  • 20 posts
  • 4 Pinsiders participating
  • Latest reply 3 years ago by dri
  • Topic is favorited by 2 Pinsiders

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#1 3 years ago

My #Judge Dredd has one last problem I think I need to fix before it's playable. Any time a 50v solenoid fires, the 12v solenoids ( not solenoids but really motors to the planet and crane ) bump just a little bit. What is very strange is that this happens even when the coin door is opened and the 50v solenoids don't actually trigger. All my power driver board's test points are at the right voltage. There's 74v at the coil solenoids. I thought it might be something leaking from the 50v line to the 12v line but when the door is open that should cut the 50v line and prevent anything leaking.

All my switches and opto's test out okay.

When this is the most annoying is when the five drop targets fall and they need to be popped up. The solenoid coil fires to reset them but it's usually too weak and that drop target module goes into a machine gun mode trying to get the targets up. This then makes the planet and crane move at almost normal speed. I wonder if I should disconnect the crane and planet motors to see if the drop target coil get's more power if they are disconnected.

I can link to a video of it happening on YouTube if that helps.

#2 3 years ago

To start with, your drop target reset solenoid shouldn't be that weak. Try putting a new sleeve in, or taking a look to make sure everything's good on the mech.

Your motors get voltage all the time. They only move when that voltage can get to ground. My top-of-the-head guess is that you've got a chip starting to fail on your driver board, and it's leaking tiny pulses to an adjoining data line. It may be leaking tiny pulses to all data lines, but they're small enough you don't notice them on the solenoids. Another possibility is that something is grounding out the returns when the machine shakes. In any case, it's not voltage related, as you can see what happens when the door is open and the 50v is disabled.

#3 3 years ago
Quoted from CaptianTim:

My #Judge Dredd has one last problem I think I need to fix before it's playable. Any time a 50v solenoid fires, the 12v solenoids ( not solenoids but really motors to the planet and crane ) bump just a little bit.

Normal when in test mode. I've had three Dredds and they all did that in test mode but not during game play. Does it do it during gameplay?

#4 3 years ago

Weird. I've had two JD's, and I don't remember either of them doing that. Then again, I see a whole lot of pinballs, so I may have forgotten.

#5 3 years ago
Quoted from CadillacMusic:

To start with, your drop target reset solenoid shouldn't be that weak. Try putting a new sleeve in, or taking a look to make sure everything's good on the mech.
Your motors get voltage all the time. They only move when that voltage can get to ground. My top-of-the-head guess is that you've got a chip starting to fail on your driver board, and it's leaking tiny pulses to an adjoining data line. It may be leaking tiny pulses to all data lines, but they're small enough you don't notice them on the solenoids. Another possibility is that something is grounding out the returns when the machine shakes. In any case, it's not voltage related, as you can see what happens when the door is open and the 50v is disabled.

I have a new sleeve and coil. From Marco. 100% matched up. Right Ohms, etc. The drop targets do get reset in Test Mode usually.

"Chip starting to fail" A LS374 or Transistor? Where should I look? I had my power driver board out recently and checked all the transistors. Had two that needed replacing. I haven't checked, nor do I know how, to check the DIPs 374s.

#6 3 years ago

Let's see. It would be...put your logic tester on pin 15 of U5. See if it flashes when you fire the drop target solenoid. If it does, something's leaking where it shouldn't be. If not, check your grounds. Make sure the driver board is screwed in well. Check to make sure the legs of Q64 are soldered well, and have no cracks.

#7 3 years ago
Quoted from CadillacMusic:

Let's see. It would be...put your logic tester on pin 15 of U5. See if it flashes when you fire the drop target solenoid. If it does, something's leaking where it shouldn't be. If not, check your grounds. Make sure the driver board is screwed in well. Check to make sure the legs of Q64 are soldered well, and have no cracks.

Pin 15 does not go low when the drop target solenoid fires. Pin 6 does. Planet turns 1/16 of a turn ( or so ). Seems to indicate the CPU and logic gates are good. Must be a bad ground somewhere or Q64. Any tips for finding a bad ground?

#8 3 years ago

Took the Driver board off, checked every transistor on the solenoid column, every diode, every resistor. Everything checked out fine. Put board back in same issue. Had a v6 ROM in my spare parts collection, tried that same issue so I put the v7 ROM back in. Issue still persists. Pulled the connector at J118 and the planet moving when bumping 50v solenoids went away ( also the motor or arm doesn't turn but that's okay for testing ).

So I think this eliminates the possibility of something under the board being shorted or loose.

Also that was my last idea and now I'm stuck again.

#9 3 years ago

Pulling the power for the motors doesn't really prove anything. Still, next I'd try taking a look at the diodes and the inductors on your motor boards.

#10 3 years ago

Signing on to this thread as I'm dying to hear the solution! It's driving me mad too...

#11 3 years ago

j118 is indeed the power. You pulled the power. Ignore this post. "drive" and "voltage" are reversed in the solenoid chart for those. It can't be getting voltage from a drive transistor...I don't think

#12 3 years ago

Checked both motor EMI boards. Diodes are fine .5v one way, 0v the other. all inductors showing .4 ohms. I think that's okay. They aren't shorted or disconnected in any way. I've been wasting so much time with this to no resolution. While I love troubleshooting I love fixing things even more.

Maybe I should just buy a Rottendog power driver board and be done with it? I wish I could rent a known good power driver board before buying one.

#13 3 years ago

What I would personally do at this point is cut the violet/blue and violet/yellow wires, and see if they still move. But don't do this if you don't think you can patch it back together.

#14 3 years ago

"If an inductor is reading very, very small resistance, less than an ohm (very close to 0Ω), this may be a sign that it's shorted. Functional inductors normally read a few ohms, greater than 1Ω and normally less than 10Ω. This is a healthy range for an inductance value. Outside this range and this is normally a sign the inductor is bad."

Maybe I'm wrong. Just googled testing an inductor and found the above. I'm pretty sure I was reading .5ohm, maybe that's too low.

Quoted from CadillacMusic:

What I would personally do at this point is cut the violet/blue and violet/yellow wires, and see if they still move. But don't do this if you don't think you can patch it back together.

Repairing that wouldn't be a problem. Where would you suggest I cut these lines?

#15 3 years ago

...pretty much wherever in the head. It doesn't matter. Some place where the wire's not tied up in a harness so you can access it. I'm almost positive they won't move, but one test is worth 1000 opinions, and all that. The idea is to isolate the motor's ground wires from the other ground wires in the game. So a break anywhere in either of them will prevent them from moving, unless there's a short to another wire.

Edit: In the head. Cut the wire in the head. I figured it was clear, but realized I never said it.

#16 3 years ago

I made a jig that skips the motor and arm pins on J127. The motor and arm don't turn as expected. I have no other choice than to believe it's on the driver board. With the arm and motor disconnected I still can't play though so it's not the arm or motor that's messing up power either. In test mode ( with those pins disconnected ) the drop target reset is strong and pops the drop targets right up, but during play it's weak and does the rapid fire ( even without the globe and arm moving ). Something else is messed up with the driver board. I can't find any bad transistors, diodes or resistors. The logic coming in seems fine with the logic probe. The voltages are at the correct levels at the test points.

If there is anyone in NE DFW that can loan me a driver board I'd appreciate it

Guess I should just go buy that rottendog board and stop wasting my time.

#17 3 years ago

Well, jumping around those wires pretty much proves that whatever it is, it's in that board. So if you decide to buy one, it will indeed fix your problem. Also, what happens with those drop targets if, say, only one is down and it tries to reset? You might have a bad switch there.

#18 3 years ago
Quoted from CadillacMusic:

Well, jumping around those wires pretty much proves that whatever it is, it's in that board. So if you decide to buy one, it will indeed fix your problem. Also, what happens with those drop targets if, say, only one is down and it tries to reset? You might have a bad switch there.

I'm going to go home tonight and clean all my opto's. They all test fine but maybe with a load something bad happens.

2 weeks later
#19 3 years ago

Finally bit the bullet and bought a RottenDog power driver board. Game plays like a charm now. I wish I could have found the problem on the original board but I didn't want to have the game sitting NOP any longer. Thanks for everyone's help. Maybe one day I'll try to solve the original's problem.

#20 3 years ago
Quoted from CaptianTim:

Finally bit the bullet and bought a RottenDog power driver board. Game plays like a charm now. I wish I could have found the problem on the original board but I didn't want to have the game sitting NOP any longer. Thanks for everyone's help. Maybe one day I'll try to solve the original's problem.

Thanks for sharing! I have a spare PD board (which has different issues, ;0) but I'll see if it makes a difference!

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