(Topic ID: 228115)

Space Invaders - Issues with Coils


By tenjuna

11 months ago



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  • 31 posts
  • 6 Pinsiders participating
  • Latest reply 11 months ago by tenjuna
  • Topic is favorited by 1 Pinsider

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    #1 11 months ago

    I have a Space Invaders I have been slowly bringing back from the dead, and last night I finally was able to get all of the chase lights working again...progress yay! Anywho, I have most of the game functional again, but I am having issues with all of the coils (except for flippers, they are fine and are not part of this discussion).

    I decided to replace all of the boards in the game with Alltek and nvram replacement boards for now, so this is not likely a solenoid board problem. What is happening is that overall none of the coils work and I am getting some weird results. The pop bumpers are all dead, except for the middle one, which for some reason inexplicably fires the left slingshot. The left slingshot itself seems to work fine. The left target bank works fine, but the right target bank is dead. Right slingshot is dead. Outhole kicker is dead.

    I am buying a new multimeter today to test wire continuity and because my cheapie multimeter is not giving me consistent Ohm readings so I can determine if the coils are simply burned out. They are all giving me ~13 Ohm readings, except for the flippers, which are 0.

    Beyond that, I confess to be a total newbie at pinball repair, but I have been watching videos and reading posts for months to try to keep me on track. Hopwever on this I am totally lost, especially with having learned last night that early Bally games are known to have coil gremlins.

    Can anyone PLEASE walk me through what I can do to properly troubleshoot this? Otherwise I am going to buy all new coils and hope for the best.

    Danke,

    Cain

    #2 11 months ago

    Step 1 is to see what happens in the coil test.
    Step 2 is to check voltage at the coils.

    #3 11 months ago

    I ordered an Alltek test board last night, but after doing some more reading it appears I was not aware of a test switch in the coin door. I will try that today along with the voltage readings after I get a new multimeter this morning.

    #4 11 months ago

    Step 3 is to repin all the connectors

    #5 11 months ago

    All connectors have been repinned, I finished that last night. With the exception of the block connectors between the head and the cabinet, I am still trying to source those along with the pins. I will pull them apart and take a look at the pins though to see how bad they are.

    Thanks for this, it's the simple stuff I am overlooking.

    #6 11 months ago

    Why would triggering the center bumper make the left slingshot go off? I have been reading for hours, and I am still thoroughly lost as to why that would happen. Any ideas?

    #7 11 months ago
    Quoted from tenjuna:

    Why would triggering the center bumper make the left slingshot go off? I have been reading for hours, and I am still thoroughly lost as to why that would happen. Any ideas?

    It could be a coil issue or a switch matrix issue, which is why it's important to check the tests. If coil test fires the wrong coil, that's different from the center bumper switch reading as the left slingshot in the switch test. Should go through both tests and make sure everything is as it should be

    #8 11 months ago

    I just ran the solenoid test (kind of embarrassed I didn't know about the coin door test switch after all this time but whatever), I get the following:

    1 - Left bank fires
    2 - nothing
    3 - Left slingshot fires
    4 - nothing
    5 - nothing
    6 - nothing
    7 - nothing
    8 - Left slingshot fires
    9 - Left bank fires
    10 - Left slingshot fires
    11 - nothing

    Will test voltage in a little bit and report back.

    #9 11 months ago

    Sorry, I wasn't holding flipper buttons, 11 triggers those and works fine.

    #10 11 months ago

    I should also state that when I first got this machine, the right bumper coil was totally burned and the daisy-chain wires were not connected. The entire assembly was locked up and was replaced with a used bumper assembly.

    #11 11 months ago

    Ok, since you've got solenoids firing twice that narrows it down.

    My first instinct would be that you repinned J4 on the solenoid board or J4 on the MPU wrong and have the signals mixed up. Did you still have this problem before the repinning? Can you double check the wire colors?

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    #12 11 months ago

    Which boards did you replace with Alltek? My first reaction in reading this thread is that something is repinned wrong, or a connector is in the wrong spot. Also, double check your coil to coil wiring as someone may have bypassed the burnt out coil in an inappropriate daisy chain. One other thing, if your MPU board is an Alltek and you have the incorrect dip switches installed for your game, you will get some very odd coil and switch behavior.

    #13 11 months ago

    Voltage test is 45.3v at all coils

    #14 11 months ago
    Quoted from BrianBannon:

    Which boards did you replace with Alltek? My first reaction in reading this thread is that something is repinned wrong, or a connector is in the wrong spot. Also, double check your coil to coil wiring as someone may have bypassed the burnt out coil in an inappropriate daisy chain. One other thing, if your MPU board is an Alltek and you have the incorrect dip switches installed for your game, you will get some very odd coil and switch behavior.

    All of the boards have been replaced. From Alltek it's MPU, Solenoid, Lamp, and Aux Lamp. From Nvram it's rectifier and sound.

    When I put in the rectifier board I found one of the pins was in the wrong place inexplicably and that ended up burning out both the old solenoid board and the Alltek that replaced it. So from then on out I have been very careful to check and double check wiring positions. From what I can tell everything is good.

    The only thing I haven't done yet is new connectors and pins in the connector blocks between the head and the cabinet, and I suspect that might be the issue. I am trying to find replacement blocks and pins now but not having much luck.

    #15 11 months ago
    Quoted from BrianBannon:

    Which boards did you replace with Alltek? My first reaction in reading this thread is that something is repinned wrong, or a connector is in the wrong spot. Also, double check your coil to coil wiring as someone may have bypassed the burnt out coil in an inappropriate daisy chain. One other thing, if your MPU board is an Alltek and you have the incorrect dip switches installed for your game, you will get some very odd coil and switch behavior.

    Oh, and I will double check all the dip switches right now. The sound is wrong, but the gameplay is correct. I suspect the Nvram sound board is the issue there and will be re-capping the old sound board and putting it back in as soon as the caps arrive from Big Daddy.

    #16 11 months ago

    Continuity test to all trigger wires checks out, and again voltage is 45.3 to all coils. Not sure what to try next, but am verifying dip switches now.

    #17 11 months ago

    My tech manual does not specify color codes for wires, am also looking for a better version so I can double-triple check wires and connectors. Again, I am very confident these are correct but I will check again.

    #18 11 months ago

    If you look at page 9 of https://www.ipdb.org/files/2252/Bally_1980_Space_Invaders_Schematic_Diagrams_paginated.pdf, the two digit codes next to each connector correspond to the wire color code table at the bottom.

    #19 11 months ago
    Quoted from zacaj:

    If you look at page 9 of https://www.ipdb.org/files/2252/Bally_1980_Space_Invaders_Schematic_Diagrams_paginated.pdf, the two digit codes next to each connector correspond to the wire color code table at the bottom.

    You win the Internet today sir, thank you kindly!

    #20 11 months ago

    Checked all of the connectors on the solenoid board, and they are all going to the correct places.

    Getting 45.3v to all coils.

    Getting continuity from the solenoid board to the coils on the trigger wires.

    Does this mean the coils are simply fried? Or does anyone have any other suggestions?

    #21 11 months ago

    For the sake of doing something, I am going to replace connectors and repin J4 on the MPU. It looks fine to me, but I cannot think of anything else to try and since I did those way back at the beginning of the project I may have thumbed it up.

    #22 11 months ago

    One more thing, I just realized I never mentioned there is no replay knocker hooked up. Can that mess with any of this?

    #23 11 months ago
    Quoted from tenjuna:

    For the sake of doing something, I am going to replace connectors and repin J4 on the MPU. It looks fine to me, but I cannot think of anything else to try and since I did those way back at the beginning of the project I may have thumbed it up.

    This was the solution...I have no idea why because everything looked ok, but repinning J4 on the MPU with another new connector fixed all of the remaining problems including the coils and the weird sound issues.

    Actually, I did add some DeoxIT to the block connector since I do not have a new one yet, perhaps that helped as well. *shrug*

    Thank you all for the assistance, I actually learned a lot from this! Should be helpful for my Eight Ball Deluxe project.

    #24 11 months ago

    Moral of the story, run your self tests and go over your connections before throwing new boards at a game.

    #25 11 months ago

    Step # 3

    #26 11 months ago

    Moral of the story:

    You absolutely have to repin every Classic Bally if you want it to be bulletproof

    There's no way around it

    #27 11 months ago
    Quoted from vid1900:

    Moral of the story:
    You absolutely have to repin every Classic Bally if you want it to be bulletproof
    There's no way around it

    This is so true. Surprisingly, even with repinning connectors being such a low cost solution many people simply don't do it. I just saw some pics of a classic Bally in another thread with many hours in the cosmetics, but still with the original connections, amazing.

    #28 11 months ago
    Quoted from BrianBannon:

    This is so true. Surprisingly, even with repinning connectors being such a low cost solution many people simply don't do it. I just saw some pics of a classic Bally in another thread with many hours in the cosmetics, but still with the original connections, amazing.

    I always reuse the original housings.

    #29 11 months ago
    Quoted from zacaj:

    I always reuse the original housings.

    I reuse the original housings as well, unless there is some issue. All those IDC connectors get tossed.

    #30 11 months ago

    Yep, reusing the plastic housings keeps the authentic look (and many are no longer available).

    I just write the rebuild date on them with a Sharpie

    1 week later
    #31 11 months ago

    Yeah lesson learned for sure. I’m repinning my eight ball deluxe before I even start on boards after learning this lesson.

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