Can you fix CRT color issues with this plastic ring?
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- Опубликовано: 4 окт 2024
- Thanks to patron Charles, let's try to fix this Sony KV-1222R's color issues with a degaussing coil. (Bonus Candy mini test!)
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Hi Adrian. When using a degaussing coil on a CRT you really should not switch it off so close to the tube. You can leave a "fingerprint" of magnetism due to the ac cycle being at the top of it peak. You really should slowly pull the coil away from the CRT and when the deflection on the beams are at its lowest switch off. Hope this helps Rob
Hi robert, I recently buyed a Sony PVM-8041q and Sony BVM-1316. the pvm grabed a color ring red in center screen.
I dont have a coil so for remove I used the bvm because this has a button to degauss, I do it a few times until the circle disappears completley but. now when the image is completely white I can see some dark circles like burned but very little distinguishable. and when is normal with image, this looks like a little brighter like a light aiming the screen. you know is this is magnetism problem or is burned? sorry for my bad english. :(
You should slowly back the degausser away while it's powered to demagnitize metals and such, just running it at proximity without slowly moving away will probably just increase the magnetic field.
Yes, this is the way that the degausser is is supposed to be used. I can confirm that turning the coil on and move it away a few times will fix these kinds of purity problems..
@@L0wcash Well, atleast it could fix the purity problem, but there is also a small risk that the mask actually is broken. But super glueing magnets on the inside of the front is always an option if the degausser wont work. And if he actually takes it apart it will be easy to spot if there are any metal on the inside of the case in that area, if not, then he could degauss forever without any results. :D
This is definitely the correct way of using a degaussing coil yes. Moving around does not probably increase the magnetic field, it most certainly will.
came here to say this. aperture grills don't look like that when broken
What kind of degausser should I buy to fix my crt? Does it matter? Thanks!!
Father was a TV repairman/AV guy. How I saw him do it back in the day (with several sets) was go in a clock ways formation for a while and then go to the center and then pull it away a good couple feet. Not sure if he then went back counter clockwise. Did that a few times but the pulling away from the center was key. Not sure if that would work in this case. I know he had to do it several times as well. Not just once.
Yes, it is quite important to remove the degaussing coil a good distance away from the CRT before turning it off; otherwise you could inadvertently magnetise part of the aperture grill/shadow mask
@@BertGrinkis there a way to tell if this has happened? I have a purity issue that wont go away and the tv have a working degauss coil
@@GigaGrandpaYT To be honest, I don't really know that, but if your TV has a manual control for the degaussing coil, you could try activating it a few times and see if it helps.
If it doesn't, then maybe it's time to get a newer TV.
@@GigaGrandpaYT Have you tried using the Coil? You can also use a TV with the exact size and place it glass to glass (but not directly touching each other) turning it on and off in front of the tv with the purity issue. TV's should have a built in degaussing system when turning on and off. it might work
you'll be able to fix the color purity with those two magnets, but they will mess up the geometry in that part of the screen. Unfortunately looks like the screen got hit there and the mask detached partially. No degaussing will fix that issue permanently. Use the monitor in that condition till it will last.
This can happen with delta/in-line tubes, but not quite with Trinitron. If the aperture grille detaches, the strings will be loose and it will affect a large area on the screen vertically, or if it detaches with its whole frame, then a whole corner will be affected. I had a 22" Trinitron that fell from about 2.5m onto a tiled concrete floor (wall mounted console got detached from the wall), the aperture grille got displaced, but it affected a whole corner, not just two tiny spots, and the spot was actually travelling on the screen very slowly (probably too big portion of the electon beams hit the grille and it heated up during use). Of course I found that out after I spent at least 2 hours repairing the traces on the board that was cracked all around the flyback. BTW szevasz, Tibi! :)
If you use a small n35 grade neodymium bar, its on the weaker end of the magnet scale and will do this same color fix but will not mess at all with the geometry. If you use a more powerful grade magnet, then yes it will
I had one of those coils as a kid, my little TV would get all messed up and degaussing it works. Your technique is the issue, what you want to do is hold it in the middle and hold the button. Then make clockwise circles with it and slowly pull the coil away from the crt while still making circles in the air. It may not fix your issue but that's the right way to use it.
It's a typical problem for stripe masks (Trinitron, Diamondtron) that the single wires in the mask start vibrating and hook into each others when lots of vibration or strong hits are applied e.g. during transport. This is the reason why Trintiron/Diamontron PC monitors have these horizontal stripes (1 for 15", 2 for larger monitors) to stabilize the wires to prevent this. The TV I think has a much more coarse stripe pitch and so does typically not need the stabilization wires, but is still prone to vibrations and the vertical stripes to hook into each others. This might be what happened with your TV.
For the degaussing coil, I agree with the others that, if it does not have a thermistor to lower down the magnetic field, you need to slowly move it away from the TV while moving it across the screen. This imitates the effect of the thermistor to lower the magnetic field in the built-in degaussing coils. Otherwise you could leave traces of permanent magnetism in the spot where you turned it off, that typically can be degaussed again but for the moment, they are there.
But I rather think you have a deformation in the stripe mask (like stripes hooked into each others), because otherwise the internal coil (which is the strongest at the border, because it is the closest to the border) would have fixed this. Giving a slight hit to the screen in the affected area might solve this, make it worse or does not have any effect at all
Bumping this comment with another comment.
I guess if some vertical strings were stuck together it would happen around the middle of the screen, not at the very edge where the strings are secured to the frame.
If I remember from my color tv repair textbook ages ago, when you finish degaussing the CRT screen, you back away, then turn it perpendicular to the screen before turning it off, and make sure before you even begin that any magnetic media was well outside the “blast radius”.
Same process I used, turning it edge-on to the screen at the end while far away is to reduce the magnetic field as gradually as possible. My degaussing coil is about 50% larger than the one Adrian used, has a momentary rocker switch in-line on the cord.
Back in the day I learned to slowly move away with the coil while moving it in a circle
Yep, that´s the same I´ve been told.
@@BertGrink and not turn it off until it's out of range.
Yes that is the proper procedure, skipping that step can make it worse
Glad you enjoyed everything.
And those Rom's were out of old Cisco system routers.
I used one of these ROM chips to upgrade the ROM in my Apple IIgs :-)
Someone gave me boxes and boxes of these old Cisco routers.... I'll be set for life. I also have these small package ones...they are Cypress CY7C245A's..... I like these a lot but I can not find a programmer that can deal with them.... perhaps an adapter? They also have a byte for security. any ideas?
@@GORF_EMPIRE The Xeltek superpro universal programmers can do this. Sometimes you can get one at ebay for about 150$.
@@elmariachi5133 I have a TL866II...it's a shame you can't program that like the old Pocket Programmer 2....which I do have one of....but that requires a parallel port. Perhaps I can use that with my old WinME laptop. IF not I'll take a look into the Xeltech. I have a ton of those chips too. Thanks!
@@adriansdigitalbasement2 at 13:23 if you take the CRT out... the problem will go away... i bet you 10 bucks on it........ what is causing that magnetic field you see in that corner... is not inside the CRT ... is outside the CRT............ a parasite CC current circulating in the degaussing coil.. i bet you 5 bucks on that (disconnect the degaussing coil.. see if the problem go away)......... if is not that.. then magnetism is in the screw on that corner.. (highly posible).. or in the bracket in that corner.. (unplug the TV for 24 hours and use a compass to find the magnetic object in that corner.. the needle will point you straight towards the south and north pole of the magnetic object there)... magnetism in the anti-explosion band also can be.... (the magnetism in those metallic objects can be removed.. using that red ring).. or with a simple electromagnet powered with 12v AC (a coil around a screw)... and leaving it close of the metallic object for a while....
That towel is becoming epic
Back in time, i often used an old Speeker magnet. And it works not so bad. THX for that Video.
I would not add magnets imside without first testing their impact on other colors and/or the image shape etc.
Yes, it probably messes up the purity of other colors, but if not, it will ceratinly mess up geometry a bit, but that's not as annoying as the original purity problem.
You only show the Red color, what about other Green / Blue ? Are they also good when you put the small magnets ?
Again, your knowledge on CRTs is simply astonishing, and you explain everything very good
I was taught using a degaussing wand. You rotate it around the front of the screen like you're pouring a soft serve ice sream (but horizontally) spiralling out from the screen starting from the outer edges to the centre moving away from it gradually.
That must've felt like doing magic
@@mjaerkens you know you've done it right when a rabbit pops out of the screen. 🐰
I had a similar problem with a 27" Sony TV. I fixed it using repeated applications of the degaussing coil. Hold it close to the center of the screen, turn it on, then slowly move the coil in a spiral pattern to the edge of the tube while simultaneously moving it in and out. Turn the coil off only when it's far enough away from the tube to stop messing with the image. Rinse, repeat. It took me a bunch of tries, but eventually the purity problem went away.
A bigger, more powerful coil might help, too. Mine was scavenged from another 27" TV. It really tweaks the screen when it's running--and it also gets effing hot!
Hope this works i got a bad spot from a guitar speaker on a 27" sony
My favorite weapon in Syndicate (the old DOS one) was always the Gauss Gun.
It's a really cool weapon in Liero too! In Syndicate that is just devastatingly powerful.
From 'accidentally' messing up my parents TV in the early 90s I found that if I caused a permanent color shift by putting one side of the speaker to the screen that it could usually be reversed by using the opposite side of the speaker.
I also messed up my partent's TV ... with a magnet. The result looked pretty much like Adrian's. It was also a Sony from this era.
@@error-u6u my parents did their best not to be angry with me when I put a refrigerator magnet on the screen
@@subtledemisefox I did that with my bedroom TV in 03 or so, stuck a big base magnet from one of those magnetic art sculpture toys on the side of the case for like 30 minutes with a friend to laugh at the colour shift.
Naturally it persisted after I took the magnet off! I just put up with it being messed up colour that day and the next day it was mostly fine, the day after that was totally fine. I guess if I’d known about degaussing then (as more than a button on computer monitors that made it jiggle) I’d have just power cycled it a few times!
I had the same thing (but a bit worse) happen when I dropped a Trinitron on the corner. I always figured the aperture grill buckled when I did it. AND kinda funny I fixed it the same way! I smashed an old magnet off a woofer into bits and glued em around until I fixed it! Might not be the problem with this one but the fix definitely works!
It's possible there might be minor damage to the shadow mask, but first I would try to locate the service manual for that model TV, or a similar Sony TV service manual and follow the proper procedure to set the purity and then adjust the static and dynamic convergence. Purity is set by adjusting the yoke and then the purity rings on the neck.
ooooh fizz sounds good. I get this fizzy candy in my japan crate from time to time. It's MY FAVORITE!
It DID have an effect. Compare frames 10:00 and 12:00 , you made the green better but the blue worse. The changes are small but they are there (view in full screen)
I've seen similar purity problems cause from external speakers nearby that weren't shielded over time. The way that I always fixed this problem, (after causing them as a kid) was to take a speaker magnet and rotate it so the color shifts, and is pinpointed in the area of the problem and use slowly move the magnet away in circles, and sometimes a sweeping motion. Yours is kind of odd, as it almost seems like it's burn in, but can be corrected with the magnets... odd. One way to place the bar magnet on the inside at the right location, would be to put the magnet on the outside, and put the inside magnet in with some build tack, and remove the outside magnet to see if that corrects the problem from the inside. If it does, you can use this to glue or epoxy it in. The round magnet is a bit trickier... maybe rotate it, sticking it to the strap that goes around the outside of the tube. Best of luck. Love those old Trinitrons.
A degaussing coil for use on crt’s is a a/c powered coil. A/c removes magnetism because it effectively flips back and forth between north and south magnetism.
And the cycle frequency will be lower than the tape eraser, as that uses higher frequencies outside of the tape’s reproduction range to overwrite a signal with (inaudible) noise. I suspect that’s why it has a more dramatic visual effect on the TV despite being weaker.
for me sir Adrian just loosen the screw of the deflection yoke and twist it back and forth and its very effective of most crt tv.
Wow, plasma effect with no code and no CPU, *that*'s a good demo!
zots are basically lemon sherberts but with more flavours, some of my favourite candies
Some years ago I was in a pub with some friends and in the part of the bar we were in there was a tv but it had very bad colour distortion. I went to the bar and asked if they wanted the tv fixing and told them that I might be able to sort it there and then and they said "yes please!", so I asked if they had a spare table that could be used, so basically I picked up the tv put it on the table turned it on and went back to the bar and said that their tv was fixed. My friends were all puzzled and also the landlord was shocked at how quick I had sorted it, so I let them in on my secret that it isn't a good idea to put a tv on unshielded speakers. Probably the easiest drinks I've earned.
Thanks for this!!
Been messing with old CRT TVs for a college project and two ot them were going a bit tripped out on me! Looked cool, but not what I wanted!
They were right beside about four big speakers I have for parties...
Moved em and all good!!!
I thought it was so cool to run magnets over my dad’s tv when I was 8. He did not think it was cool.
My guess would be that one of the magnets that were originally used to tune the CRT’s characteristics in the factory has fallen off or is somehow not magnetic anymore...?
I 100% agree
Since its a corner/border color impurity uncorrectable with degaussing, this is probably the case. Maybe an old impact knocked something out of place
This is how I fix my magnetized CRTs: I put the screen of the monitor that doesn't have the degaussing step on "boot" right in front of another one that does have it and turn it on but I actually don't remember if I turn on the one that doesn't have it before the other but you got the idea.
Wow Zotz! Those bring back good memories :)
@9:30 I remember those fizzy-centered candies! They seemed to disappear in the early '90's for some reason. I'd mostly forgotten about it.
Definitely warped shadow mask, because of heat or mechanical stress in the past. Your tape degausser is better than the plastic one sent to you. Other than that, they do the same job. The key is to switch it off away from the crt, thus creating a fading to zero magnetic field. Your approach with the permanent magnets is correct, as long as you check all the colors and convergence before you install them. Most likely there were such magnets (typically in the form of adhesive magnetic tape) installed from the factory that got detached, as others have already said.
Glue Both the Magnets to the tube itself in that corner, thats what i had to do on an older set that was dropped by some one, they wanted me to fix it and the problem was similar to that, like some thing in the tube broke or some thing, so i just stuck a Magnet on the Corner that had the Issue and it worked great after.
I don't know much about the detailed workings of TVs involved here, but if you don't already have 1 it might be useful to get 1 of those magnetic field visualisers (places that sell wide selections of magnets usually sell them). You might be able to use it to find whatever has been magnetised by moving it over the relevant areas with the TV powered off.
There's a fine art to sticking small permanent magnet strips to the picture tube to correct for beam misalignment. It's not a perfect solution, but good enough to keep a consumable product functioning more satisfactorily until it's lifespan has passed. Depending on how careful you are with the magnet placement and how serious the misalignment is, you can sometimes get away with the really weak ferromagnet adhesive-backed refrigerator magnet sheets, then you can cut exactly the size you need and adhere it to the tube once you figure out where it needs to go. You may be able to get away with using an even smaller neodymium magnet epoxied to the corner of the CRT behind the bezel.
I am not home right now (so I have to watch the video later), but the service manual for the Sony Trinitron of my latest video mentioned stick on magnets and a comment pointed to 'crt yoke magnet strips'...
I used to use speaker magnets to get rid of magnetised areas
I had an ancient TV for my C64 when I was a kid that I stuck magnets to, to try and fix weird warping on the screen. I worked more or less. I was just happy to have my own screen.
Many of the CRT monitors I owned way back had a degauss button right on the monitor. It always zapped the monitor pretty violently.
Looks like its a convergence/purity issue, since the magnets you stuck on there fixed it. The problem is that is will continue to get worse, at least in my experience. Had a beautiful 32" Wega Trinny, and it had been dropped when I carried it, enough that it knocked a few of the magnets that the factory had installed on the back of the tube itself had come loose. I stuck a ton of weaker ceramic magnets and magnet tape to it, and I got the picture looking beautiful. Then I turned it off..and when I turned it back on, there were brand new issues in areas of the tube that never had them before. So, again, I popped the back off, set up my mirrors, and started tacking on magnets. Again, got it fixed, looked great, worked great for a couple of days..and then new issues again. Eventually I must have plastered close to 25 magnets on the tube itself, but I think that the aperture grill inside the actual tube must have gotten damaged in the fall (even though it didn't fall far, it was enough). I did give up on it after about a month, but I mean I tried everything...magnets, deguassing with a smaller PC monitor set on top of it, setting another tv in front of it, using a drill, but in the end, I didn't have the knowledge to fix it. Since its small enough, the magnets might do the trick though, but in time it might cause damage. Good luck!
When we did this back in the early 90s, we had to walk towards the screen and then away from it with the degausser turned on. Otherwise, we'd at best have no effect and at worst make it a lot worse. We called it the "degaussing dance".
i've had this issue once back in the 90s i used a big strong magnet from a car speaker or something and i basically massaged it, after a few tries i fixed it.
Check the bell housing of the tube, there should be magnets that can make minor adjustments to the tube. Check all 3 colors. The magnets could have fell off also. Some older tubes have an adjustment ring around the neck attached to the yoke of the deflection coil. Sony as well as other brands did at one time sell magnets kits for tweaking the tubes when replacing a bad tube.
Yes unfortunately I think this set has has suffered a knock at some point, though you may be onto something with those permanent magnets.
With degaussing, the quick 'n' dirty method was to place another TV or monitor screen-to-screen with the problematic set, and then power it up separately from cold to initiate its degauss. A bit like jump-starting a car!
As others have mentioned, moving the coil away slowly whilst rotating rather than turning it off mid-way close to the screen is generally considered best practice.
Haha that’s an awesome way to source a coil!
Going down the troubleshooting rabbit hole, you could try taking the CRT out of the housing to establish where the fault stems from. Had it been dropped, some plastics would be broken, and the grill wouldn't just come loose without any trauma to the CRT. One guess is that the TV has been sitting next to a speaker for a long period of its life, and that something may have caused something else in the case to become much more magnetic.
I've heard from an expert that dropping a CRT can cause purity issues. It warps the aperture grille.
I actually had a 14 inch Sony TV that has similar problems, but worse. I could get the color spots to go away with careful movements of a speaker magnet but if you turned the TV off and on again, the Degauss would actually restore the purity problem. Leaving it on standby won't re-trigger the degauss.
256k EPROMs make for great multicarts for old systems like Atari 2600, VC4000, Colecovision, Vectrex...
so I always used a larger degaussing ring and I generally moved slowly away from the crt in a circular motion... but that is just how I did it...
Yes, degaussing consist to apply a decreasing cyclic (up/down) magnetic field.
@@danielktdoran duly noted
I had a guitar amplifier that turned our 36" crt tv purple after I left it in the living room for a few days. My mom called a TV repair man who came out with a degausing coil and couldn't get it fixed. He said he needed to go get a different coil and would be back, but he never showed up.
You may stuck with it, but an old TV manual I had (published in 1959 or so) said that you can take an inductor of some sort and connect a MAINS power cord to it to use as a degauser. Perhaps you could build a wand similar to that.
I am not an expert but generally according to the theory demagnetizing works so that you need a changeing magnetic field (reversing north and south poles) and over time the strength of the field should also decrease. This way the magnetized metal will lose its magnetic field due to the hysteresis losses. So from a degaussing coil I would except when it is turned on that it should wiggle the picture. Since it was not happening I guess it does just generate a static field. Maybe rotating it around its axis (face front side of the coil and back side of the coil) could do the trick. Then increasing the distance would decrease the field strength and would demagnetize.
Since the power line runs at a very similar frequency to the scan rate the effects appear static.
@@eDoc2020 good point :) In the past I had a SyncMaster that could do degaussing from the menu. There it was clearly slower then the scan rate judging from how the picture was wiggling. From this I have expected that a degaussing device will use a lower frequency than the power line frequency.
@@andrashuszti1407 Usually when I've seen degaussing in action it's had the shaking; when I first saw a "static" one I was a bit surprised. I think the explanation is that we were probably running 70Hz or higher at the time.
I have a Sony Triniton KV-1430E. Many years ago I played (stupidly enough) with a magnet from an old speaker close to the screen, causing a permanent colour blob on the screen. But I was able to make it disappear by "massaging" the screen with the magnet. As I recall I could kind of "move" the blob by brushing the magnet over the blob in the same direction.
Can you also check the metal ring that holds the XY scan coils is not loose or has slipped back down the kneck(scan coils have slipped back away from the flare end of glass)..hard to explain...aka make sure the scan coils are pushed fully up-tight to the tube..
The white tape under the metal ring/clamp slips when warm..and moves slowly back over time .
Often, these TVs had disc magnets stuck to them on the edges, you might want to take this apart and look for them in case they got unglued.
If the problem was physical damage to the aperture grille, it would certainly not be located in just a small corner, it would affect the entire screen.
Adrian doesn't need to hear all of this, he's a highly trained professional.
@@ozmobozo this comment is brilliant and highly under appreciated
Also have the TV had a bump?. shadow mask buckled?
The stray magnetic field exists "ON" the shadow mask itself and not in any other part of the CRT (scan coils). Magnetic buttons, with known magnetic properties, were available from Sony for dealing with spot shadow mask magnetic contamination like this. They are stuck to the rear of the CRT envelope, on the grey aquadag coating, where they are found to neutralise the magnetic contamination/distortion.
If the deflection coils were the cause, then you would more likely have subtle convergence errors too, including some bizarre geometry distortions too.
Reminds me of the pure joy of hitting the degause on a computer lab full of chunky white Dell monitors.
Seen this before. There will be a grounding wire stretched around the CRT. Sometimes it’s misaligned and needs repositioning. I’ve done this fix on TV’s many times and hopefully this time it’s nothing more complicated than that? 🙂
Sultans of swing... Foolin' around in the corner... 😂... Cool. "Then a crowd a young boys they're a foolin' around in the corner"
I wonder if the tube was left near a strong magnet for a long period of time and it warped the aperture grill.
No, it's probably impossible. But Trinitrons have a very thick, heavy frame for the aperture grille, it might be possible that a strong magnet magnetised the frame so strongly that these degaussers are not stong enough to demagnetize it.
Great explanation. But all you need to do is adjust the purity ring set on the convergence rings. Should fix that right up…in theory.
You can also use a soldering gun
Look for a disk choke on the board in that area. Sometimes they come off or get loose and will distort the picture.
Hello. before I used to glue on small magnets to get rid of things like that. ferrite or nedium magnet from small speakers or refrigerator magnets you put on the door
I miss Zotz.
I just added that same bag to my cart.
get a big magnet from a speaker woofer, and wave it accross in either corner away from the tv, it should fix it
I have waved hard drive magnets at a good distance in a figure eight pattern and recovered monitors, so any magnetic force can fix blemishes for a good while
I hate CRTs with passion. Once, as a kid, I got a second-hand monitor so busted I had to keep twiddling the focus control on the flyback every few minutes. When I got the center right, one corner was getting blurry and vice-versa so I learned to settle on "all corners more or less equally bad" setting. I have put an elastic tube on the internal flyback pot and drilled a hole in the monitor's back cover for it just to be able to twiddle the focus all the time. I'm pretty sure I have accelerated the degradation of my eyesight using this thing. I remember how happy I was getting my first LCD like it was today. Having said all this, I cannot resist watching Adrian's each and every video on CRTs back to back. I find his fondness of this technology that was so much worse than modern displays in each and every way imaginable fascinating. I am grateful for people like him who have so much respect for our technological legacy and are working so hard to preserve it.
Wouldn't the added magnets that fix the red cause issues with the green and blue? Just curious, I am not a CRT guy but I am learning a lot from these videos!
Open the tv up and probe around in it with one of the magnets. Probe both the tube and the retainer while paying very careful attention to how much force you feel in your fingers. Alternatively, if you have a flux or gauss gage you can probe around with it.
I made one of these coils once with an extension cord and half of a spool of 14/2 shaped into a square with electrical tape. 🤣
Don't know about the degaussing issue, but I will note that Sony seemed to like putting the speakers in the top of the television in the 80s (maybe 70s too?), though my later 90s-era Sony TV has it on the side, so I guess they changed their minds at some point, probably because a top-mounted speaker filled with dust and debris... :)
I think those EPROM chips were used by the old PSION organiser packs. You could erase them using UV light.
Yeah, clearly it's a permanent thing on that tube. Seems like you will have to take the tube out of the chassis and see if that changes anything, and if not, try to fasten the magnets somewhere on the tube where they make the problem go away. From what I remember, the degaussing is just about giving the grid a reset in case it has gotten out of position. They're quite susceptible to magnetic fields, as demonstrated. Either there's a magnetic source causing it, or the grid is misaligned. I suppose it could be worth trying the degauss ring around the neck of the tube rather than around the corner only, but I doubt it will work considering how stubborn it seems to be - it didn't change at all.
Use an extremely strong speaker magnet. Such as the type you find on a car speaker.
you should watch how shango does it, you start very far away
That looks like something magnetically "hard"- those magnets should have left a permanent impression, but whatever's inside seemed to overpower them.
Is their perhaps a stray wire near that side of the screen that's come loose/magnetic shield that's come detached/rusted.
No hope of degaussing untill that's fixed, if that were to have happened- it would just remagnetise it.
I have a similar problem with a CRT monitor in the lower left corner as well. Unfortunately not many of my available monitors will work with my PS/2 due to insistence on having 14 pins rather than 15, so my options are limited.
Maybe the built-in degaussing coil is damaged in that corner, do you have any others from broken CRT Monitors/TV's that will fit?
I'm no expert, but could it be possible that leaving the magnets in place over an extended period of time might help?
Your supposed to make circles and "pull out" in each rotation, think and invisible large screw that goes like four feet in front of your tube/mask.
Good fix, I would hot glue them on.
degaussing won't fix the stuff in the lower left corner. there's an adjustment magnet that has moved or perhaps the metal band around the face of the tube itself is magnetized. I don't think it's the grill, but I don't know for sure. Usually a grill displacement has a much more dramatic discoloring effect than that, in my experience.
I would use one of those neodymium magnets to try to demagnetize the metal band around the face of the tube in those locations, or, more likely, between them. pass a strong one, separated by paper or plastic, back and forth along the metal band around the face of the tube in that corner for a couple minutes, then see if it has improved. if not, no further work is required because I'm wrong.
I would check the thermistor for dry joints first. It might have been knocked damaging the the mask slightly.
If it is a magnetic problem i wonder if just leaving the magnets in place for a long period might fix the issue
I’m wondering if the metal frame at the front inside the TV has become magnetised?
Some CRT's have magnets stuck to the funnel part of the tube to correct deflection problems. Maybe one fell off, or is too week ?
and old trick i have used take a pc monitor that has a degause option and stick the screens together and then do the degause it should do both monitors at the same time i mean stick glass to glass or as close as u can get 9 times out of 10 will fix a monitor that doesn't have said option
May need a very strong but localized field to correct it.
Have you checked that the yoke hasn’t moved slightly over time? I’ve had a similar problem before where I had a discolouration on the side of the screen as a result.
aperture grill remembers me of aperture science emancipation grill
I always thought a true degaussing was to flip the magnetic field north/south very fast.
My understanding is that initial "bzzzt" you hear as the degauss activates is the result of the reversing of the field back and forth quickly for about a half second...
That's exactly what Adrian said, the TV set feeds 50 or 60Hz mains through the degaussing coil, so the field reverses at that rate.
Honestly, if I had to guess, the screen was placed near something hot. Remember that those shadow masks are super thin grids of metal. I don't know if a heat source could deform that metal without melting the plastic, but it's a possibility.
From such intense heat input, not just the plastic frame would melt (and burn), but also the glass would crack.
I bet that set was dropped or took some sort of hard thump at one time. Does rapping the glass or the side of the set cause the raster to change?
Macs-ed out on Mac memory modules? I'll see myself out.
@adrian. Are any of the screws magnetised near the tube? That could cause it.
Very fiddly used to get it when someone put a speaker near a tv
💪😎👌
Interesting, but... I'm wondering if it's also possible to use this degaussing coil in other way? I'm not an crt expert but I'm wondering if it can be used on open box tv-set and placed somewhere in the area of electron guns. (at the "end" of crt tube (or perhaps at the "beginning" taking into consideration that it's the source of electrons). Moreover I'm wondering if any regulation of electron guns deflection could help here. Probably there is Sony service manual somewhere on the net with detailled procedure. Just some ideas... They might be wrong as I said I never repair any crt's.
Also where was the TV manufactured?.. UK?