This is not really going according to plan.


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28 Responses:

  1. pmb7777 says:

    it looks like the CRT is expecting a DC offset signal, and it's getting AC.

    • jwz says:

      It wasn't working, then it started working fine, then stopped. We scoped the analog output going from the logic board to the monitor assembly and that's fine, so presumably a component on the monitor itself is loose/flaky.

      • pmb7777 says:

        Ugh, then. I know I have less fun debugging my toys when I'd rather be playing with them. FWIW, this gave me some inspiration last time I was working on something similar.

      • dr_memory says:

        I heartily recommend the guys over at Tilt Electronics -- they've brought my Tempest back from the dead several times. They can be a little difficult to get ahold of (it's basically three guys), but they do excellent work and stand by their warranties.

        FWIW (probably not very much; I imagine you've tried this already), the last time my Tempest started displaying the "half a screen" problem (it looked pretty much exactly like your screenshot there), it was fixed by the simple expedient of scrubbing all of the corrosion off the big connectors to the mainboards with a wire brush.

  2. elusis says:

    Is this where I get to say "there's literally ones of polygons!"?

  3. tcpip says:

    Dammit, I remember those games from my childhood and I can't remember their names...

  4. Mike Ashmore says:

    My friend Doug has restored more than a few arcade cabinets in his time - including the Tempest machine here where I work. He advises that this is a horizontal deflection issue, totally common failure mode, usually traceable to cold solder joints on the monitor board's connectors or on the heatsinks on the transistors driving the horizontal deflection circuitry.

    If you don't find cold solder joints, test the bottle-cap transistors that those control board connectors are attached to. If you find a bad one, Doug's probably got a spare you can have.

    • Mike Ashmore says:

      (forwarding on behalf of Doug):
      Monitor manual:

      ASCII guide:

      Big FAQ:

      In approximate order, I'd check:

      1) Big chassis-mounted transistors Q605, Q606 (2N3716 and 2N3792)
      2) Cold solder joints on P600
      3) Cold solder joints for Q603/Q604 (heatsinked transistors on deflection board), and/or failed transistors here.

      If tapping on the connector with the game on "fixes" the problem, even for an instant, it's cold solder joints on either P600 or near Q603/Q604.

      If you pull the deflection board for inspection/repair:

      1) Be careful when removing the connector to the degaussing coil, as well as any screw that might be present in the corner of the board that's nearest the tube. I've never had a monitor discharge on me through this path, but it's really easy for the back of your hand to make contact with the tube here.
      2) If you don't plug the degaussing coil back in when you test, flameproof resistor R106 (22 ohm, 3W) will let out some smoke.

    • netik says:

      After going through the board with my scope and looking over the schematics I was fairly certain it was the deflection transistors. I guess we'll have to replace them or check solders.

      It was very, very cool to see the game on my scope, though.

  5. Eric Jones says:

    You didn't ask but...bad deflection transistor. No soldering required.

    It's either a 2N3716 or a 2N3792. Tempest takes 2 of each. Get a few of each for spares.

  6. So let me get this straight - when jwz says "help me lazyweb" and "please don't suggest stupid fucking things" he gets useless stupid fucking things; when he doesn't ask, he gets well-informed psychic debugging and detailed troubleshooting guides.

    • hatter says:

      He's not asking about stuff that a million dumbasses would like to think they're experts in.

      the hatter

      • jwz says:

        That's the thing about dumbasses, though. Had I actually asked a question about deflection coils, I'm sure I would have gotten suggestions about Guitar Hero controllers or Xbox Live.

    • pmb7777 says:

      It helps that he's describing a common failure of a 30 year old machine built with $0.10 parts, instead of asking how to repurpose modern mass-produced consumer electronic equipment. Modern electronics brings "no user serviceable parts inside" to a whole new level.

    • ryanlrussell says:

      Correct. I have observed that when he asks for help, fail ensues. When he claims it cannot be done, people do free engineering research.

      • thumperward says:

        That's always been the way of the Lazyweb. Ask how to do something and you'll either get a hundred useless answers or silence. Claim it can't be done and you'll get a "yes it can dumbass, see this detailed PDF" back in three hours.

        - Chris

  7. ts4z says:

    Vectorlist is a mailing list with some very knowledgeable folks. I would start there.

    Or if you just want to pay somebody, T-Minus One does repair and will be reasonably familiar with this. They're in the Bay Area and regularly make house calls to the city anyway.

  8. hadlock says:

    I have this problem with my guitar hero if I try and plug in the connector upside down while connected to XBox Live. Try logging out, and then flipping over the connector. It should solve the problem.

  9. While replacing the Y deflection transistors *might* solve it, it's usually a good idea to install a full capacitor replacement kit (cap-kit). You'll need a cap-kit for a WG 6100.

    The best place to get them is either ($20) or Bob Roberts -- ($14). Neither web site looks very impressive, and neither is a classic ecommerce site. They're both reliable though.

    Bob is very old-school, but also cheap, knowledgeable and reliable. He won't take credit cards or paypal, but once you get on his good side, he'll cross ship (which is to say that he'll ship immediately, and trusts you to mail your check immediately.)

    I've got 4 games that use them, so I've rebuilt 6100's several times. They're not that hard to work on. As long as you're not playing with anything in the HV cage, discharging the high voltage isn't strictly necessary.

    • Oh.. and though it's called a cap-kit, it will have the main deflection transistors as well as a few other parts that tend to degrade over time.

      • cranaic says:

        I love that there is an underground community of Tempest owners, and that they are in this thread, handing out nuanced advice.

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