(Topic ID: 234309)

Can you diagnose / locate a G.I. short with a multimeter?


By beefzap

7 months ago



Topic Stats

  • 32 posts
  • 14 Pinsiders participating
  • Latest reply 6 months ago by tktlwyr
  • Topic is favorited by 10 Pinsiders

You

Linked Games

No games have been linked to this topic.

    Topic Gallery

    There have been 3 images uploaded to this topic. (View topic image gallery).

    6E27C004-DEEC-4110-9387-1D4A02CED93B (resized).jpeg
    20180111_203119 (resized).jpg
    20190122_211633 (resized).jpg

    #1 7 months ago

    Is this possible? I am blowing F109 on my Shadow. No obvious issues with any of the bulb sockets.

    If not the next step would be to first replace all the bulbs, then start replacing the sockets I think.

    Would be nice to ID the bulb/socket that is most likely the culprit.

    #2 7 months ago

    You disconnected the GI connectors to make sure it is not the board itself blowing the fuses? After that, look closely at all the sockets in the bad string looking for bent contacts, solder globs, etc. Next remove all the bulbs in that string to increase the resistance between the +/-. Measure across a socket with a meter to see if it is a short. If it is a short, inspect all the sockets again and find a socket half way down the string and desolder the wires from it. At that point you will have the string isolated into two halves of 6 or 7 sockets each. Measure resistance across a socket in either half. Hopefully one half the sockets will be good at this point and you can now concentrate on the other half. Divide the string in half again and again and measure with the meter each time until you isolate the bad socket.

    #3 7 months ago

    I am having the same problem with my FT after shopping out. F108 keeps blowing. It's not the board and cannot find anything funny with any of the sockets. I suspect pop bumper sockets since I removed them all of them and replace one socket. Still, I don't see anything touching metal and not really sure how to use the multimeter for things like this.

    #4 7 months ago

    Is there a circuit breaker you can put in place of the fuse? Google searching comes up with all kinds of stuff but not sure what will work. That would be handy until I can figure out the issue. Gone through a bunch of fuses already.

    #5 7 months ago
    Quoted from jawjaw:

    Is there a circuit breaker you can put in place of the fuse? Google searching comes up with all kinds of stuff but not sure what will work. That would be handy until I can figure out the issue. Gone through a bunch of fuses already.

    I have a few of these auxiliary circuit breakers originally designed for boats. They're rated up to 32V DC so don't try to use them on high-powered flipper circuits. The quick disconnect style has spades that are spaced in a way that sometimes you can just wedge the circuit breaker onto the fuse holder.

    amazon.com link »

    #6 7 months ago

    I would suggest finding the source of the resistance rather then putting a bandaid on it. To blow a fuse there must be a pretty big problem some where. But like John said just keep removing parts until you track down the source you will find it eventually.

    #7 7 months ago

    Two things that are hard to see that will cause fuses to blow.

    One is chaffed wires where the insulation is rubbed away exposing the conductor that is grounded against the metal. Look for that GI string of wires where is may be touching a bracket or other metal part under the playfield.

    Another thing I came across a few times was a bad bulb. Typically the whole GI string would be very, very dim for a while and then the fuse would blow. I found that by doing the 'remove all the bulbs and add them back in one by one' method.

    #8 7 months ago
    Quoted from schudel5:

    Two things that are hard to see that will cause fuses to blow.
    One is chaffed wires where the insulation is rubbed away exposing the conductor that is grounded against the metal. Look for that GI string of wires where is may be touching a bracket or other metal part under the playfield.
    Another thing I came across a few times was a bad bulb. Typically the whole GI string would be very, very dim for a while and then the fuse would blow. I found that by doing the 'remove all the bulbs and add them back in one by one' method.

    I assume you start adding back in from the front of the string? asking cause unsure

    #9 7 months ago
    Quoted from Whysnow:

    I assume you start adding back in from the front of the string? asking cause unsure

    Adding back in the lamps? Doesn't matter where you start because the lamps are in parallel. As soon as you put the bad lamp in, the string gets dim or the fuse blows.

    #10 7 months ago
    Quoted from schudel5:

    As soon as you put the bad lamp in, the string gets dim or the fuse blows.

    Why not just test the lamps with your multi-meter? The one with way lower resistance is the bad one. You could wire up a known good socket with test leads to clip onto if you had a bunch to test.

    #11 7 months ago
    Quoted from YeOldPinPlayer:

    Why not just test the lamps with your multi-meter? The one with way lower resistance is the bad one. You could wire up a known good socket with test leads to clip onto if you had a bunch to test.

    If only I had remembered to bring it with me on location...

    #12 7 months ago
    Quoted from schudel5:

    Adding back in the lamps? Doesn't matter where you start because the lamps are in parallel. As soon as you put the bad lamp in, the string gets dim or the fuse blows.

    Any idea about the best way to diagnose on a Spike system?

    GoT pro. the string of GI with left sling, left inlane, right sling, right inlane, and under sword lock are dim (about 70% of normal brightness/as other GI strings).

    I replaced all bulbs one by one and they are all dim, no matter what order. I can not find any physical issues.

    #13 7 months ago
    Quoted from Whysnow:

    Any idea about the best way to diagnose on a Spike system?

    No idea on Spike. I'm pretty sure all the GI comes from the node boards.

    #14 7 months ago
    Quoted from schudel5:

    No idea on Spike. I'm pretty sure all the GI comes from the node boards.

    It does. A single connector for that string.

    #15 7 months ago

    You can narrow it down with a circuit breaker fuse. Put in the breaker fuse, disconnect the gi connector and turn on. Slowly plug in the connector and watch which pins spark. Look for a short in the wire colors of the pins or pin that sparked.

    #16 7 months ago
    Quoted from RatShack:

    I have a few of these auxiliary circuit breakers originally designed for boats. They're rated up to 32V DC so don't try to use them on high-powered flipper circuits. The quick disconnect style has spades that are spaced in a way that sometimes you can just wedge the circuit breaker onto the fuse holder.
    amazon.com link »

    Thanks for tip. Bought one and soldered on some clips I had laying around. It works great. Nice not wasting a lot of fuses in testing. Think I finally figured out my short last night. A drop of solder spilled on a lamp socket from working on the pops. Cleaned that off and that looks like it's fixed.

    #17 7 months ago

    Ah ha, great troubleshooting!
    Feels good to kill that gremlin eh?

    #18 7 months ago
    Quoted from jawjaw:

    Thanks for tip. Bought one and soldered on some clips I had laying around. It works great. Nice not wasting a lot of fuses in testing. Think I finally figured out my short last night. A drop of solder spilled on a lamp socket from working on the pops. Cleaned that off and that looks like it's fixed.

    lets see that badboy, I want to make one of these for testing. where did ya get the breaker?

    #19 7 months ago
    Quoted from Atari_Daze:

    Ah ha, great troubleshooting!
    Feels good to kill that gremlin eh?

    Sure does. It wouldn't be so bad if I hadn't just finished doing a ton of work over the last few months. Sick of working on it and just want to play it for a while.

    Quoted from ccbiggsoo7:

    lets see that badboy, I want to make one of these for testing. where did ya get the breaker?

    I bought the one RatShack posted in 5A configuration. Less than $6.
    amazon.com link »

    Here is what I did in action. I later wrapped the terminals in electrical tape. Friend suggested that and good idea.

    @beefzap - You figure out the short in your Shadow?

    20190122_211633 (resized).jpg
    #20 7 months ago

    Here is how I did my breakers.

    20180111_203119 (resized).jpg
    #21 6 months ago
    Quoted from jawjaw:

    Sure does. It wouldn't be so bad if I hadn't just finished doing a ton of work over the last few months. Sick of working on it and just want to play it for a while.

    I bought the one RatShack posted in 5A configuration. Less than $6.
    amazon.com link »
    Here is what I did in action. I later wrapped the terminals in electrical tape. Friend suggested that and good idea.
    @beefzap - You figure out the short in your Shadow?[quoted image]

    Nope not yet, will try to work on the issue tomorrow, once solved I will post the gory details

    #22 6 months ago
    Quoted from Whysnow:

    It does. A single connector for that string.

    How much power is that connector delivering? If the power output's low, there's a bad component on the node board.

    #23 6 months ago

    Found the GI short in a sopranos I had with a multimeter and a friends help. We would get intermittent continuity on the bulb socket tabs if we messed with the socket. Took a while to find, but yeah it worked.

    #24 6 months ago

    With J121 out the fuse does not blow. Checked a few sockets and a couple looked like they had some solder so removed it. Now the fuse does not blow but no GI lights at the back left playfield still. Damn....

    #25 6 months ago
    Quoted from beefzap:

    With J121 out the fuse does not blow. Checked a few sockets and a couple looked like they had some solder so removed it. Now the fuse does not blow but no GI lights at the back left playfield still. Damn....

    How are the J120-J121 board connectors? They tend to build up resistance over time due to the non-stop current load on them. Do the pins look bright? Does the plug have trifurcon connectors in it? How do they look? Some pictures would be helpful.

    #26 6 months ago

    You running led or incandescent bulbs? Either way, I would take a known good bulb and try them in the sockets that don't light just to be sure. If that doesn't work and fuse is not blowing, sounds like there is a broken wire in the string.

    #27 6 months ago
    Quoted from jawjaw:

    You running led or incandescent bulbs? Either way, I would take a known good bulb and try them in the sockets that don't light just to be sure. If that doesn't work and fuse is not blowing, sounds like there is a broken wire in the string.

    Checking for a broken wire in a GI string is dead simple with a multimeter, just set it to continuity and check from socket to socket. If one shows no continuity, there's likely a broken wire in that segment.

    2 weeks later
    #28 6 months ago

    Just now getting back to this. Replaced 2 sockets that had solder all over the place. Turned the machine on and the GI was on for about 5 seconds. Then poof. Fuse is blown as well.

    No chaffed wires.

    I will try replacing all the bulbs next and see what happens.

    #29 6 months ago

    Well....they are on. I am leaving the machine on for a long time so I can just look at them.

    So it was either solved by replacing all the bulbs or I did find a wire (not chaffed) that was pinched in between on of the socket connectors. Pulled it out.

    I am not declaring victory yet.

    But thanks for all the help on this.

    #30 6 months ago

    Thanks for the follow-up post. It's nice to have resolution to these trouble threads for future people that may have the same issue.

    #31 6 months ago

    Sounds like you made good progress so that's a win in my book.

    #32 6 months ago

    In case anyone saw this Flash Gordon thread:

    https://pinside.com/pinball/forum/topic/whats-my-flash-gordon-worth-1

    None of the problems left in the machine were related to his plugging in the the small transformer to the backbox. It was the bare power/ground braid in between a GI and controlled lamp socket. Every time the controlled lamp would flash, as it does in attract mode, POOF!

    Moved one socket and some shrink tubing fixed it right up.

    6E27C004-DEEC-4110-9387-1D4A02CED93B (resized).jpeg
    Promoted items from the Pinside Marketplace
    From: $ 42.00
    Cabinet - Shooter Rods
    ModFather Pinball Mods
    $ 12.00
    Playfield - Toys/Add-ons
    Meph's Mods
    $ 23.25
    Cabinet - Shooter Rods
    The MOD Couple
    $ 159.99
    Lighting - Other
    Lighted Pinball Mods
    $ 29.95
    $ 12.00
    Playfield - Other
    Slap Save Creations
    $ 22.00
    Playfield - Toys/Add-ons
    ModFather Pinball Mods
    From: € 2.00
    Electronics
    TheDudeMods
    $ 45.00
    Playfield - Toys/Add-ons
    Great American Pinball
    From: € 25.00
    Flipper Parts
    TheDudeMods
    $ 19.95
    Playfield - Toys/Add-ons
    ULEKstore
    $ 30.99
    Lighting - Interactive
    Lee's Parts
    From: $ 13.00
    Electronics
    Third Coast Pinball
    $ 20.00
    Playfield - Plastics
    Pinball Haus
    $ 5,799.00
    Pinball Machine
    Little Shop Of Games
    $ 159.99
    Lighting - Other
    Lighted Pinball Mods
    $ 5,599.00
    Pinball Machine
    Classic Game Rooms
    $ 16.95
    Playfield - Toys/Add-ons
    ULEKstore
    $ 999.00
    Flipper Parts
    Mircoplayfields
    From: $ 42.00
    Cabinet - Shooter Rods
    ModFather Pinball Mods
    From: $ 11.95
    Playfield - Toys/Add-ons
    ULEKstore
    $ 69.99
    Playfield - Toys/Add-ons
    Lighted Pinball Mods
    $ 229.99
    Lighting - Other
    Lighted Pinball Mods
    From: $ 99.99
    Cabinet - Other
    Lighted Pinball Mods

    Hey there! Got a moment?

    Great to see you're enjoying Pinside! Did you know Pinside is able to run thanks to donations from our visitors? Please donate to Pinside, support the site and get anext to your username to show for it! Donate to Pinside