Build Your Own Arcade Controls Forum
Main => Main Forum => Topic started by: Charles4400 on November 02, 2008, 10:41:25 pm
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I assume the green wire is the ground???
(http://i5.photobucket.com/albums/y152/Charles4400/DSC09559.jpg)
If so (or even if it isn't ) where do I attach it?
Thanks!
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It is the ground wire. Attach it to the frame of the machine with a screw. I attached mine to the hinge on the cp.
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I attached mine to the other ground wires on my microswitches for my controls. Ground is ground.
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Thanks all!
By the way is there a designated up direction....or do you calibrate that later?
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I have the GroovyGameGear.com Electric Ice-T Trackball (which is a modified Betson Imperial Trackball) and these are the instructions that came with it. (Courtesy of Randy T from GroovyGameGear.com).
If you mount it in your panel and are looking at it from underneath, the wires should be on the lower left when mounted properly. (See Diagram)
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perfect! Thank you DeLuSioNal29 !
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I attached mine to the other ground wires on my microswitches for my controls. Ground is ground.
I guess you don't like your machine very much. It's not a ground in the electrical sense - it's a ground to dissipate static buildup! Better hook it to the ground wire on the mains.
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Man there is always a lot of confusion about that darn green wire. I wish vendors would stick some description in with their products to keep us from arguing about it every few months.
The consensus on here in the past is that it is a static ground wire, and should be connected to an "earth ground" in order to reduce static electricity from drawing dirt and dust to your trackball. From what I gather from previous threads on this subject, the easiest way to do this is to attach it to one of the screws on the back of your PC that holds in your power supply.
However, these green cables are also very short. Mine won't reach my PC. And, it would make removing the control panel top very difficult since I'll have to reach in and unscrew it from the power supply before I can take the cp top off.
Anybody know where else it might be safe to attach this wire?
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Just extend the wire with and attach it to a case screw. That's the easiest way to do it.
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Interesting. I stand corrected. I've never had a problem, but I'd rather be safe than sorry. I will reconnect it tonight.
As for the unscrewing part... You could always use "Quick" disconnects like I do for my LED power on my control panel.
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I'm glad this question was brought up, as I"m about to start wiring my control panel.
So I should be OK daisy chaining all my control grounds and running a wire to a screw on my case?
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Lots of great info...thank you all!
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Now I'm thinking... Could I also attach the ground to the molex connector (black wire - ground) instead of the screw on the case? This would be easier for me, since I already have this ground source in my panel for the LED lighting.
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Here's a good best practice way to do things. There are sometimes reasons to violate these rules, but this will usually get you a pretty optimal setup.
You have two "grounds" in your cabinet. One is Earth ground (aka "Frame", aka "Safety Ground", aka "The third prong on your AC plug"); it's usually green or green with a yellow stripe, but you'll also frequently see big braids. The other is "power common" (aka "negative", aka "DC-", aka "ground") and is conventionally black. So, the question is what to do with them.
Earth ground is pretty simple. Hook everything that is exposed metal but otherwise not power related to it. This would be things like your coin door, CP hinges, exposed bolts, etc. This prevents static buildup and also serves a safety purpose of catching any electrical faults inside the cabinet by forcing the exposed metal to be "safe" to the touch. Ideally you'd run big-honkin wires from each metal part to a single point, but it's also fine to just daisy chain metal chunks one to the next.
Power common is used for power (duh), signal common (like the common ground bus on your CP switches), and other DC power related things. You'd use this when running power to DC devices like DC coin lamps, button LEDs, keyboard encoders, etc. and for the return/reference on I/O like switches, trackball signals, etc.
You shouldn't mix them together all willy nilly, but they do tend to get connected together at your monitor: your monitor has a signal coming in to it for the video but also has exposed metal parts that get grounded to the earth ground. This "weak connection" (it's a physically large loop) can result in interference patterns. If this happens, try connecting the grounds together with a good solid connection at one point. Conventionally, this is right at the DC power supply. For you PC users, this is already done as all PC supplies do this internally.
The reason for all this separation is that unexpectedly large currents can flow on the earth ground network in order to keep everything at the same potential (voltage): this is what prevents static buildup. The side effect of this is that "ground" isn't always quite the same on that earth ground network due to line loss caused by these currents. Remember that voltage is all relative (that's why your multimeter has two probes), so the voltage difference seen at various points in the cabinet would differ simply because ground isn't always at the same potential. Separating power/signal ground from earth ground fixes this problem. The reason that tying your grounds together with a good solid connection at the power supply can fix monitor interference issues is precisely this reason: all those currents will flow over that "solid" connection rather than going over your monitor wiring (which is a relatively "weak" path).
It's also best to try to avoid mixing high current loops (like power runs for your game boards) with low current signals (like button returns) on your DC power common for similar reasons as mentioned above. For example, running your video ground straight back to your power supply rather than using the pin on JAMMA would not be advised (this is in fact one reason why JAMMA has a dedicated video ground pin).
Now, all this is the conventional "best practice". These rules get violated all the time, and usually it's no big deal. However, if you're having ground related issues like coin doors that static zap you or scrolling horizontal black bars on your monitor, you may want to check out your ground configuration and see if it can be improved.
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I just tested a regular USB cable, and on my system the GND signal line is tied directly to the CPU chassis (dead short). IOW, if you are connecting the green wire to the GND of your encoder, then it's most likely going to be fine.
RandyT
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Earth ground is pretty simple. Hook everything that is exposed metal but otherwise not power related to it. This would be things like your coin door, CP hinges, exposed bolts, etc. This prevents static buildup and also serves a safety purpose of catching any electrical faults inside the cabinet by forcing the exposed metal to be "safe" to the touch. Ideally you'd run big-honkin wires from each metal part to a single point, but it's also fine to just daisy chain metal chunks one to the next.
So, just to paraphrase and see if I'm catching this right: on my cabinet I have a piano hinge that holds the CP top to the CP box. If I were following best practices, I should be running a ground wire from the piano hinge to a grounding spot on my computer? Even though the piano hinge isn't in contact with anything electrical, but because it is exposed metal?
I don't plan to add a ground for the piano hinge, but I'm new to wiring and I'd like to understand.
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Earth ground is pretty simple. Hook everything that is exposed metal but otherwise not power related to it. This would be things like your coin door, CP hinges, exposed bolts, etc. This prevents static buildup and also serves a safety purpose of catching any electrical faults inside the cabinet by forcing the exposed metal to be "safe" to the touch. Ideally you'd run big-honkin wires from each metal part to a single point, but it's also fine to just daisy chain metal chunks one to the next.
So, just to paraphrase and see if I'm catching this right: on my cabinet I have a piano hinge that holds the CP top to the CP box. If I were following best practices, I should be running a ground wire from the piano hinge to a grounding spot on my computer? Even though the piano hinge isn't in contact with anything electrical, but because it is exposed metal?
I don't plan to add a ground for the piano hinge, but I'm new to wiring and I'd like to understand.
Yup. Both cabinets I own with a hinged panel (Midway MK2 and a Neo Geo candy) in fact have this hinge grounded. The MK2 grounds it to a giant ground strap that runs the "length" of the cabinet, and the Neo Geo takes it to a central ground point near the power inlet. Of couse, if it doesn't bother you and isn't causing problems, then there's not a whole lot of reason to obsess over this.
I just tested a regular USB cable, and on my system the GND signal line is tied directly to the CPU chassis (dead short). IOW, if you are connecting the green wire to the GND of your encoder, then it's most likely going to be fine.
For grins, test it with the power supply COMPLETELY disconnected (all mobo power cables, disk drive cables, etc) but the PC still in the case. The power lines in a PC are pretty beefy, so the connection inside the PSU can easily read as a dead short. USB is fortunately somewhat immune to ground shifts due to the diffential signalling.
PCs do tend to play fast and loose with the earth/power ground separation, though. Some hard drives (for example) tie power common to their metal frames. It doesn't usually cause problems; I was just giving "best practice" advice. This practice is frequently ignored with no serious consequences, but sometimes it bites, and being careful can rectify eerie problems that are otherwise difficult to diagnose.
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PCs do tend to play fast and loose with the earth/power ground separation, though. Some hard drives (for example) tie power common to their metal frames. It doesn't usually cause problems; I was just giving "best practice" advice. This practice is frequently ignored with no serious consequences, but sometimes it bites, and being careful can rectify eerie problems that are otherwise difficult to diagnose.
I know, and as always, your explanations are a great read and much appreciated. I just wanted to put people, who may not have it hooked up "optimally", at ease. If the grounds are tied together in other parts of the system (as my test pretty much concludes that they are), then as a practical matter, there's little difference in running the separate wire. If one has some sort of issue with their controls, certainly consider these possibilities. But there's probably no reason for concern or need to re-wire if everything is working properly.
RandyT
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Just wanted to :applaud: the explanations given here -- MonMotha's post should be part of a "Wiring Your Cab" article in the wiki.
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PCs do tend to play fast and loose with the earth/power ground separation, though. Some hard drives (for example) tie power common to their metal frames. It doesn't usually cause problems; I was just giving "best practice" advice. This practice is frequently ignored with no serious consequences, but sometimes it bites, and being careful can rectify eerie problems that are otherwise difficult to diagnose.
I know, and as always, your explanations are a great read and much appreciated. I just wanted to put people, who may not have it hooked up "optimally", at ease. If the grounds are tied together in other parts of the system (as my test pretty much concludes that they are), then as a practical matter, there's little difference in running the separate wire. If one has some sort of issue with their controls, certainly consider these possibilities. But there's probably no reason for concern or need to re-wire if everything is working properly.
RandyT
Heh, didn't mean to imply you were doing anything bad or wrong. I "violate" those rules all the time (and sometimes pay the price with flaky operation during the winter time...), especially when trying out new stuff and the cabinet wiring is being constantly changed. I was mostly looking for another data point. Some PCs will intermix the two all willy nilly and others are pretty good about maintaining the separation, and I was just curious as to which category yours falls in. Regardless, in all PCs using PC power supplies, DC power common will be tied to earth ground at at least one point: inside the power supply.