How to add earth ground.

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    • How to add earth ground.

      Hi Everyone!

      I wanted to get another set of eyes on this to get some ideas on what I can do to add earth ground, or 3 prong plug to this Wei-Ya 429H chassis.

      here’s the schematic! I’m having trouble figuring out which is neutral and which is hot. Also, I can’t imagine where to ground the dang thing.

      Any and all help is greatly appreciated!

      Thanks!
    • fairly certain phase doesn't matter after an isolation transformer. Since isolation breaks the connection to ground, the AC lines are the same as each other.

      If your monitor requires isolation, don't try to run it without a transformer. Doing so risks shock etc.

      This is a good read for anyone working on monitors teaganm.cademo.com/images/other/randyfromm/isoxfmr.htm

      The post was edited 3 times, last by skate323k137 ().

    • Isn't it typical in cabinets for earth ground to be tied directly to to the monitor frame/chassis independent of the isolation transformer?
      Woodies: Xevious, Pac-Man, Centipede, Dig Dug, Donkey Kong, Joust Cocktail, Space Invaders, Initial D3 Single, Mortal Kombat II, Zaxxon, Galaga, Space Shuttle Pinball
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    • KaPH33n wrote:

      Isn't it typical in cabinets for earth ground to be tied directly to to the monitor frame/chassis independent of the isolation transformer?
      arcadecontrols.com/BBBB/acwiring.html

      Seemingly not according to the Bob Roberts AC Wiring guide.

      Don't ask me though, I avoid monitors with isolation transformers, I just looked this up, ha.
      On the hunt for: Dinoking, Mushiking, Love & Berry, Egret 29, and an SNK SC-25.

      Shameless plug: Rewrite's Recaps - Your monitor and PSU recapping service center
    • From that link...



      In that diagram it shows the monitor connected to Earth Ground via green wire with ring terminal.
      Woodies: Xevious, Pac-Man, Centipede, Dig Dug, Donkey Kong, Joust Cocktail, Space Invaders, Initial D3 Single, Mortal Kombat II, Zaxxon, Galaga, Space Shuttle Pinball
      Candies: 2x Aero City, New Astro City, 2x Blast City, Net City
      Other: Wacky Gator, Shoot the Moon, Movie Stop, Premier Crane
      VAPS
    • KaPH33n wrote:

      In that diagram it shows the monitor connected to Earth Ground via green wire with ring terminal.
      It looked to me like that was connected to the iso transformer, but I see now that it is just INCREDIBLY CLOSE TO the iso transformer.
      On the hunt for: Dinoking, Mushiking, Love & Berry, Egret 29, and an SNK SC-25.

      Shameless plug: Rewrite's Recaps - Your monitor and PSU recapping service center
    • thegreathopper wrote:

      live is the connection with the fuse, Hot is that an Americanism? Hot is live and Neutral is the other AC connection without the fuse.
      Correct but at the end it doesn't matter.
      Of course I still make sure to wire things as they should, only to discover neutral and phase are swapped inside the walls or at the electrical panel, sometimes both (double inversion so no inversion only wrong wire colours, may be even more dangerous).
      Looking for:
      - faulty Hang-On, Space Harrier or Enduro Racer (2203 sound board)
      - Sega Mega-CD 1 power board
      - Super Nintendo CPU (3 needed)



      "I'd 1cc games but I have a real life."
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    • I posted about CRTs before, and I will say again that I am unfamiliar with them. I hope that if any part of my post is wrong, someone will correct me.

      That said, I would like to say that from looking at the schematic, both lines pretty much immediately enter a bridge rectifier, so worrying about Live and Neutral shouldn't matter for this application functionality wise, but the configuration of the fuses on the board would be what I would go by for safety.

      You want a fuse closest to the entry of Live so that a fault that blows the fuse will leave the greatest portion unconnected and "safe". For this specific example, I would, without having more information, attach Live to the line that has "F1" on it, and neutral to the remaining AC line. The other line has a fuse as well, "F2", but it is slightly downstream of the mystery component "DGC" that sits before the PTC. Without knowing what this is, I would prefer to have Line on the side protected by F1.

      For earth ground, the metal frame of the monitor (as well as other things in a cabinet that are metal like control panels and coin doors) should be connected to a central grounding point somewhere directly connected to the earth wire of your 3 prong plug, but nothing directly on the chassis board since it has no provisions for anything. Do not under any circumstances wire earth to neutral despite both earth and neutral under non-fault conditions theoretically being at 0 potential.

      Edit: I needed to look at your schematic a bit more carefully. There are ground symbols littered across the schematic.
      I suspect your chassis screws into a metal bracket / board holder/tray or something.
      If so, continuity check one of the grounds in the schematic to the mounting bracket. If it checks out, that's where you want to connect earth.

      The post was edited 1 time, last by adgenet ().

    • Hi Everyone!

      Thank you so much for posting all this info! It’s a great start to building my foundational knowledge as I move forward!

      Here’s the main reason why I’m asking.

      I’ve included pictures of the Wei-Ya 429H chassis, the two AC lines (one with white dashes and one with out), what I think is the isolated transformer (outlet inside the AWSD), and the 3 prong cord running from the isolated transformer to the chassis.

      What do I do with the earth ground wire from the 3 prong cord running to the transformer? I’ve tried grounding it to the indicated ground screw inside the AWSD, grounding it to a ground screw located on the wood plank that the PSU sits in, and grounding it to a screw on the metal frame that the chassis sits on. All of these locations have resulted in me getting a little shock when I go to turn on or turn off the cab.

      Please let me know if you have any suggestions! Also, sorry for this. I know it’s annoying to have to answer these rudimentary questions, but promise I’ve been research and trying things before posting again.

      Thank you so much for your time!
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    • Report2Marty wrote:

      what I think is the isolated transformer (outlet inside the AWSD)

      The pics you attached don't show an isolating transformer. The outlet is just that, an outlet, nothing else.

      Can you take a pic showing the full cab interior?

      I was going to say the 429H doesn't need an isolating transformer, but apparently it does:

      forums.arcade-museum.com/showpost.php?p=2413280&postcount=7

      News to me.
    • @nem thanks for clearing that up! I want sure if the purpose of that outlet and I stupidly assumed it was an isolated transformer... I’m an idiot... here are pics of the interior.
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    • You're using the outlet for its intended purpose. But you put a monitor in there that doesn't fit the original cabinet design (that is having a monitor installed that doesn't require an isolation transformer).

      Since it turns out that this replacement monitor requires an isolation transformer you're going to have to find one and wire it up (see the guide @KaPH33n corrected me on as far as wiring is concerned).

      As for what to buy or if all iso transformers are created equal, someone else is going to have to answer that.
      On the hunt for: Dinoking, Mushiking, Love & Berry, Egret 29, and an SNK SC-25.

      Shameless plug: Rewrite's Recaps - Your monitor and PSU recapping service center