Grounding Coin Door

[DaOld Man]

On the second arcade cab I built I used the now discontinued Keywiz Eco-2 with the ide connector.
The keywiz all of a sudden began giving "stuck key" errors on the computer.
After much trouble shooting I found that the encoder was sending random 5's and 6's to the computer.

I removed the encoder and tried it on my desktop computer with same results.

After talking with Randy from Groovy Game Gear via email, he suggested that perhaps static electricity from people inserting coins probably damaged those two inputs on the keywiz. (5 and 6 are coin 1 and 2)

He asked me if the coin door was grounded.

"Doh!!"

On the 4 cabs I have built, I dont remember grounding any of the coin doors.
So now I got to go back and ground them.

Just thought I would post this as a reminder to everyone to take a little extra time and run a wire from the metal part of the coin door to the computer case, or another suitable ground point.
I am talking about earth ground, not the ground on the keyboard encoder.
(The metal part of your computer case should be earth grounded through the wall outlet.)
I already have all the trackballs grounded in this fashion, but it just never occurred to me to ground the coin door.

Thanks to Randy over at GGG for his help.

[scream1973]

Since i am in the building stages and not quite ready for wiring quite yet..

What should i be grounding in my cabinet to a metal point ?


Coin door as you mentioned

Anything else

I will have Ipac , U360s , Utrak and buttons with LED-Wiz..

The USB connections i assume provide ground to those pieces.. LED-Wizs with LEds will ground to the power supply ground.. Ipac will ground to the same way.

Please correct me if i am wrong  or missing anythign else.

[DaOld Man]

Im not real sure, but I would say anything with a metal frame that is not attached to ground through an electrical connection, such as usb. (In other words, the metal frame not connected to the electronics).

The trackball is one such device, especially if you use the metal mounting plate.
The metal part of the trackball is not necessarily connected to the ground of the electrical cable coming into it.
And to my pain, neither is the coin door (or at least coin doors that use micro switches, I do not know about coin doors with electronic coin mechs.)

Another interesting device could be a spinner, I dont own one so Im not sure about it.

One way you can test it, with power turned off, use an ohm meter and measure from the computer case (metal part) to the frame of each of your devices. If it reads very low ohms, (0-5) resistance, then you should be ok.

EDIT: the above ohm meter test should be done after you have all your devices wired in and connected to the computer, just leave power off during the test.

[SavannahLion]

A couple of side notes.

Make sure that you actually have a complete path ground. I've come across cheap ---steaming pile of meadow muffin--- power strips that lack the ground line. Crack the thing open and found that some punk was too lazy or some bean counter too cheap to solder a simple ground lead on the plugs.  I also lived in a home where about 1/2 of the wall sockets weren't properly grounded. I kept getting shocked by my PC and kept getting weird behavior until I figured this little nugget out. I won't tell you what I did to fix it, but I can tell you I ended up with a proper ground in the end. 

If you're not certain, Rat Shack and home improvement stores sell this little "Ground Tester" thing[/ur]. It doesn't cover every condition (that I can recall) but it's a nice handy device. I have one only because I can't remember to carry my multi-meter every place I go. A better method is to learn how to use a multi-meter so you can do a more detailed analysis. With a MM, you can determine if the rest of the cab is properly grounded or otherwise.

[boardjunkie]

Any metal piece that is exposed to the player should be grounded for safety reasons....