Phantom magnetic field in my basement

darthphunk

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Hey guys.

I discovered something weird about my basement. There is a small patch of magnetic interference in one of the sections and I am not sure what is causing it.

I noticed it when I was working on my Super Pac Man. I don't do cosmetic work in the basement, but I will do all other work on a game down there. I was putting a new monitor in the Super Pac and I was having problems degaussing the monitor. I worked on it for a while and was getting frustrated. I turned the cabinet a little when I was working and I noticed that when I turned it, the distorted monitor changed. I scooted the game around and discovered there is a small area with magnetic weirdness.

FaPUL.jpg


This is not to scale, but this is what the room looks like. There is no interference when the games are by the walls. There is also no interference in the wall mounted CRT tv above the bar. I only see the distortion if there is a game sitting in the green area (which is where I was working on Super Pac)

This is an old home, built in the late 30's. There are no pipes above and minimal electrical cables running directly above the site (1 cable to power a light near there, but not directly over)

The floor is cement with a hard corrugated plastic subfloor, with OSB, then a thin styrofoam vapor barrier, then laminate flooring... nothing in the cement like cut off bolts or old brackets or anything.

I am thinking there is something weird in the ground directly underneath that area. Any ideas beyond DONT PUT GAMES THERE? Can I shield this?

I won't be putting games in that spot, because it's a walkway... but there is room for a cabaret or two on the wall just under the phantom zone and I don't want to damage anything.
 
Have you seen it affect any other games? It's normal to turn a monitor and have the colors change - that's because the Earth's magnetic field affects the CRT. That will happen anywhere. Also, I've had some monitors where the frame got slightly magnetized at some point, and were hard to degauss - it took repeated degaussings, focusing on the edges of the tube, to clean it up.

Another possibility is that your house was built on top of an ancient Alnico Indian burial ground.

-Ian
 
Have you seen it affect any other games? It's normal to turn a monitor and have the colors change - that's because the Earth's magnetic field affects the CRT. That will happen anywhere. Also, I've had some monitors where the frame got slightly magnetized at some point, and were hard to degauss - it took repeated degaussings, focusing on the edges of the tube, to clean it up.

Another possibility is that your house was built on top of an ancient Alnico Indian burial ground.

-Ian

I checked Klax when I moved it into place and there was interference as well. And I didn't turn the monitor to see the colors change.... I turned the whole cab. Where Super Pac is now... the colors don't change if I turn the cab.

Also I don't think it's Alnico. The phrase A DA NV S DI keeps appearing in blood on the walls. A quick Google search tells me this is Cherokee for "LEAVE".
 
There are some common things that will cause this, most notably minerals in the ground below the house. A small vein of lodestone or a nickel-iron meteorite would cause these sorts of things. Sometimes the rebar used in concrete will become magnetized and cause this sort of thing.

Having a whole row of video games powered up nearby can cause localized magnetic disturbances as well. Everytime I rearrange my machines, I usually end up degaussing a bunch of them.

The only thing that you could if you can determine that it is coming through the floor would be to create a shield by putting a steel sheet under the laminate to act as a magnetic barrier.
 
Did you try moving the game into it's final position and turning it off and on a couple of times? The degaussing coil that comes with the monitor will usually clear up issues caused by the earth's natural magnetic field.
 
Did you try moving the game into it's final position and turning it off and on a couple of times? The degaussing coil that comes with the monitor will usually clear up issues caused by the earth's natural magnetic field.

Yeah. Still have discoloration on the lower 3 inches of the monitor.

I got most of it cleared up with a power drill. I have a proper degaussing coil on the way to give it a go.
 
Yeah. Still have discoloration on the lower 3 inches of the monitor.

I got most of it cleared up with a power drill. I have a proper degaussing coil on the way to give it a go.

That sucks. I've actually had to use small magnets to clear up color issues on some monitors. I've had one or two monitors where a corner of the frame or metal band around the tube would get magnetized and I was able to use a degauss coil to clear it up. I placed the small magnets on the frame. On one monitor I was ablet to remove the magnet and the image stayed corrected, on the other I ended up adding some epoxy so the magnet wouldn't shift later.
 
There are some common things that will cause this, most notably minerals in the ground below the house. A small vein of lodestone or a nickel-iron meteorite would cause these sorts of things. Sometimes the rebar used in concrete will become magnetized and cause this sort of thing.

Could be a vein of gold or silver under your house ☻
 
take an old compass, and move around the area, the compass will be affected by the magnetic field.
 
I wanted to resurrect this thread because I have been seeing similar weirdness with my Joust. It has a GFCI on the wall behind it (but it's not plugged into it), and also has to be next to an extra refrigerator that we have. I've been noticing that the screen gets a very minor jitter every now and again, and it seems to go away when I pull the game away from the wall. May need to swap it around and see what happens.
 
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