Minor electric shocks from Stargate

[andykmv]

I only have one step-down transformer which I use for both the Defender and Stargate, but I've not had an issue with the Defender's grounding. They're not cheap down here (New Zealand), so I wouldn't want to buy a new one unless I was sure it was the problem. (This is not a transformer that came with the game or that has anything to with arcade games - I needed to run the games on local voltage, so I bought the step-down separately.)

firstly, get yourself one of the mains power point testers with the three lights from your local electrical or hardware shop. the diagnostic lights should tell you if you have a mains earthign issue in the house first. if that''s the problem, get a sparkie to fix it first.

with the game turned off/disconnected of course, fix your games earthing wiring by remove each earth termination point in turn, cleaning the lead end and the termination point to return the connection to good condition, each in turn. replace any suspect braids/earth leads. re-test from the start as above for each suspect joint repaired.

if house earth at your game connection point is ok, and your earthing points are all good, but still getting zapped, then try measuring the voltage between the mains Ground (green) wire (where it comes in to the cab), and the metal parts (that are giving you a shock), on the 250-600v volts AC scale on the multimeter. safety first! you may only get once chance with mains voltages! just be careful not to shock yourself on exposed live ac supply wires/circuits in the process. if in doubt put some sort of insulating barrier between yourself, and the exposed high voltage/ac circuitry you may be near whilst measuring. OR better yet get a sparkie to give you advise and/or make the measurements/check the circuits for you.

if you are seeing a significant voltage on the metal parts, and (in each instance after disconnecting your game from mains power first , and temporarily but safely insulating any exposed live wires/circuits/leads before re-powering your game) ie if problem still exists then (in each instance after disconnecting your game from mains power first , and temporarily but safely insulating any exposed live wires before re-powering the game to do measurements) try
1. disconnecting the monitor ac supply and signal leads (leaving the earths, monitor iso trannie and switcher psu connected) then re-test the voltages again between the earth input and the metal parts.
2. disconnecting the monitor isolation transformer ac supply (leaving the earths, switcher psu and monitor connected) then re-test the voltages again between the earth input and the metal parts.
3. disconnecting the switcher power supply (leaving the earths, isolation trannie and monitor connected) then re-test the voltages again between the earth input and the metal parts.

that should give you an idea if you have some sort of leakage or short from Active/Neutral to earth, and where the fault may lie, either in the mains isolation transformer, switcher power supply , or possibly monitor.

if you have an earth leakage detector extension cord, try connecting your game through that. if it trips, you'll need an expert if you cant find it.

Safety first!

 

[YellowDog]

Or if you are feeling lucky. The Williams transformers were wired to accept either 110VAC or 220VAC by redoing the plug on the AC wiring harness. Pull up the Stargate schematic and you will see a note about how to redo the wiring to accept 220.

As to the ground, the AC voltage should go to the two lugs on the line filter and the ground should go to the center lug attached to the case of the line filter. The steel braid should connect to the case of the line filter via one of the screws on the side that hold it. I would check the connectivity (with power off) between the ground plug on the line cord and the line filter and also to the braid at various points. It is possible that some of the connections with the braid (typically a screw through two or more layers of braid) have corroded or been removed in an attempt to fix something. If you don't have connectivity between the ground pin on your line cord and the metal in the control panel, that is a problem that needs to get fixed.


ken

 

[saltbreez]

Or if you are feeling lucky. The Williams transformers were wired to accept either 110VAC or 220VAC by redoing the plug on the AC wiring harness. Pull up the Stargate schematic and you will see a note about how to redo the wiring to accept 220.

+1

Saltbreez

 

[dahnz]

First off, thanks yet again to all those who made suggestions, and I particularly appreciated Andykmv for going to all that trouble to write that advice out. The good news is that I fixed it and it turned out to be something very simple - the ground pin on the power cable from the cab (all original, as far as I can tell) had oxidised (or at least gained a good layer of crud) enough to stop a good grounding. I tired rubbing it with some steel wool until it was shiny new and plugged it back in and problem solved! So I celebrated with a good hour or so of Stargating without having to worry about shocking myself when I twisted the joystick violently.

Thanks also to Yellow Dog for that tip on the transformers. I had wondered about that, because my Robotron just ran off NZ power without appearing to have had any major alterations to the power supply, but I didn't know if they put different transformers in for the international market. Will this work on Defender too? It would be nice to restore my Stargate to the original Williams PS and to run it and Defender straight off the local mains.

Now I just need to replace the ballast on my Stargate. Would you believe that in this country you need to get a sparkie to do that? And I need to order some T12 tubes from the States, because they're quite rare here. I also have monitor issues with my Defender and Robotron (A G07 and a WG4600), so I may well be asking more questions soon in the monitor forum.

Cheers everyone, Dominic

 

[YellowDog]

First off, thanks yet again to all those who made suggestions, and I particularly appreciated Andykmv for going to all that trouble to write that advice out. The good news is that I fixed it and it turned out to be something very simple - the ground pin on the power cable from the cab (all original, as far as I can tell) had oxidised (or at least gained a good layer of crud) enough to stop a good grounding. I tired rubbing it with some steel wool until it was shiny new and plugged it back in and problem solved! So I celebrated with a good hour or so of Stargating without having to worry about shocking myself when I twisted the joystick violently.

Thanks also to Yellow Dog for that tip on the transformers. I had wondered about that, because my Robotron just ran off NZ power without appearing to have had any major alterations to the power supply, but I didn't know if they put different transformers in for the international market. Will this work on Defender too? It would be nice to restore my Stargate to the original Williams PS and to run it and Defender straight off the local mains.

Now I just need to replace the ballast on my Stargate. Would you believe that in this country you need to get a sparkie to do that? And I need to order some T12 tubes from the States, because they're quite rare here. I also have monitor issues with my Defender and Robotron (A G07 and a WG4600), so I may well be asking more questions soon in the monitor forum.

Cheers everyone, Dominic

Rather than putting a US fluorescent setup in, take a look at your Robotron and see if the power running to that fluorescent is 110VAC or 220VAC. If you look at the wiring diagram, you will see that both the monitor and the marquee lamp run off the iso coils on the transformer. I can't tell if rewiring the primary for 220V will translate to 220V coming off the iso or if it cuts it in half (110V). If the voltage is not cut in half, then one of your local fluorescent light fixtures may work. Then you would have locally available parts.

Also if it doesn't cut the AC in half, you may have to modify the monitor to take 220.

If somebody else on 220V has done this please chime in.

ken

 

[andykmv]

It just has to be said - i'm surprised no one else did )

This is God's way of telling you that you should never play Stargate. It was made by the Devil to coerce players into thinking it was fun because it was a "game", when in reality it is a diabolical damnation that should be driven from your home with a crucifix and holy water.

There's a reason why the cab was painted with the red and yellow flames of Hellfire....

It just has to be said - if you can't stand the heat stay out of the kitchen!

Williams Rocks Whoo Hoo!