21–30 of 59 posts
Was fun to understand the election beam was being deflected a magnetic field at the time tho
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A magnet will bend the electron beams, but that isn’t permanent. A permanent color change made by a magnet only happens by imposing a magnetic field on a metallic component of the monitor, so that the beam is always deflected by it. One component not shown in that diagram is the shadow mask, which divides the screen into discrete dots to be activated by the electron beams. This is a very thin piece of metal (or a gri…
I can't believe the author skipped this part. I felt terrible unsatisfied with the article. Thank you!
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Correct, the field of the Earth is weak and won’t mess up the image on the TV.
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…
Some family was over visiting and the adults were sitting in the adjoining dining room with us kids in the living room by the TV.
Lightning struck somewhere close by and a tennis sized ball of electricity entered the dining room through the outside wall. It crossed the room in about a second, went through the wall to enter the living room and then accelerated towards the TV.
When it hit the TV box the TV went out and the house lights flickered for a bit, but everything seemed fine. We turned the TV back on and it had a big purple corner which the degauss function couldn't fix.
Overall it probably lasted about a week before the effect faded enough that it was no longer visible.
That's incorrect: there aren't many CRTs in a TV or monitor. There's just one in monochrome displays or three in color displays. That paragraph even seems to imply that there is one CRT per dot. I don't think you would even need magnets to guide electrons (much less one set of magnets for all the CRTs): just aim each CRT at the correct location. Seems a weird misconception from someone who calls themselves a physicist.
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.
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).
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
All quality CRT TVs are automatically de-gaussed on switch-on. That's the 'toooong' you hear when they turn on. A magnet might temporarily mess up the magnetic convergence with magnetised spot areas, but that should be fixed on next switch-on. The Earth’s magnetic field can also affect the picture That's because when the convergence controls are set correctly, they also take care of the magnetic field of the earth to…
My dad (at the time a technician maintaining TV transmitters) finally fixed it by power cycling it a few dozen times.
He told me that if he hadn't known how it works I'd have had the hiding of my life...
> There are many CRTs in your TV or monitor. They are each aimed to deliver electrons to a precise spot on the back of your TV where they excite the phospor in the tiny spot on your TV that the electron hits. Magnets are used to guide the electrons to that precise (and tiny) spot. The excited phosphor molecules at that spot then emit light. All the CRTs working together generate the picture on your TV. That's incorre…
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.
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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 abo…
People frequently rotate CRTs for arcade games. They're fine.