[kamilner]

There's a throwaway comment in here about the earth's magnetic field affecting CRTs and turning the TV upside down, is that actually true? I would have thought the earth's magnetic field would be incredibly weak in comparison to the deflecting coils.

[TheBigSalad]

I've had TVs move room to room and face a different direction and need to be fixed with a degaussing coil. I'm told it's from the Earth's magnetic field. Could also be that they were next to other TVs (arcade machines in this case).

[wholinator2]

If i had to guess, i bet it's the other machines nearby. I'm sure we've all felt the static from a crt screen when it's turned off. Being in a closed room of turned on crt's would probably create a significant field of potentials around the room. I can't imagine the earth's magnetic field is so erratic as to change noticeably from room to room. I'd think any variation of that order would disrupt the functioning of compasses, and the phenomena couldn't just be localized to your one room on earth, compasses would be somewhat unreliable all over the globe then.

But who knows, maybe a solar flair hit you between rooms and changed the environment enough to disrupt the tv, but then i'd bet it'd effect all the machines. Eh, who knows. Weird thing that electromagnetism

[toast0]

I've got a cocktail video game, and the top (which the screen is mounted to) is on a hinge. There's a decent degauss on start, so if you start it with the screen up, it's fine, and if you start it with the screen down, it's fine, but if you move it while it's on, the colors get weird.

[LocalH]

Rotation can affect image purity. You don't even have to turn the set upside down. If you have a set that already has some color purity issues due to bad magnetism of the mask, you can affect that (and sometimes even find a position that eliminates it) simply by rotating the TV around on the surface it rests on.

[ksaj]

I just sent an email to my old high school buddy. I'm sure this is incorrect, and I've asked him for his remembrance of something we did on a lark.

One night David Letterman did an episode where throughout the show, the camera(s) did a full 360 degree revolution.

When the show was half-way through, it was of course, upside down. So we turned the television upside down.

I personally don't remember anything unusual about the way the show appeared, other than that the TV was upside down, and then on its side for a few minutes at the 45 minute mark.

If he responds within a reasonable time, I'll follow up to mention if he remembers this the same way I do.

[hammyhavoc]

People frequently rotate CRTs for arcade games. They're fine.

[db48x]

Correct, the field of the Earth is weak and won’t mess up the image on the TV.

[degauss]

Incorrect.

The earth's magnetic field definitely affects Cathode Ray Tubes and many other things.

High end CRT computer monitors came with a built in degaussing system and some had controls for aligning the R,G & B electron beams.

https://en.wikipedia.org/wiki/Degaussing https://hackaday.com/2016/05/25/wtf-is-degaussing/

From personal experience, I took a 20" Sony Trinitron from Los Angeles to New Zealand in the mid 90's. the reversal in the Earth's magnetic field between the northern and southern hemisphere's meant I could never completely get the RGB guns to line up correctly.

https://www.webopedia.com/insights/monitorhemispheres/

[plastic3169]

Some professional Sony BWM series monitors have menu settings for the direction where the monitor is facing to compensate for the earth magnetic field.