CRT question - will degaussing fix this?

[SamIAm]

I should probably search for a more appropriate forum to post this, but I thought I would ask here first since I'm not a member anywhere else. I just picked up a TV which has a color problem, and I would be grateful if anyone with experience could tell me whether it sounds like using a degaussing coil is likely to fix it.

The TV is a Sony Trinitron CRT from 2005, and it's discolored in the upper corners. On a pure white screen, the upper right corner is yellow, and the upper left corner is blue. Using the 240p test suite and its fullscreen red/blue/green/white/black function, it's easy to see that blue is weak in the upper right, and red is weak in the upper left. Green is slightly weak in both. The blue is especially bad.

However, if I take a weak refrigerator magnet and put it near the trouble spots on the screen, the problem goes away. I have to use the opposite poles for each corner, but it works. Unfortunately, it returns seconds after pulling the magnet back.

The delivery guy dropped the set once, by the way. It fell maybe six inches. It was padded, though.

There do not appear to be any convergence problems based on the 240p suite's grid tests. It's solely colors.

Degaussing coils aren't really expensive, but they aren't cheap. The TV itself was only $40. However, it has an otherwise great picture, and if this sounds like a textbook "needs a degaussing" I would love to know.

Thank you!

[cjameslv]

Take a hair dryer and rub the back part (air intake side) about 1/2" away from scren in swipe motions. kinda like your wiping the discoloration away. It can take a few min to get it. I have had fair success with this on my arcade monitors so i think this would work for crt tvs as well.

[CGQuarterly]

Take a hair dryer and rub the back part (air intake side) about 1/2" away from scren in swipe motions. kinda like your wiping the discoloration away. It can take a few min to get it. I have had fair success with this on my arcade monitors so i think this would work for crt tvs as well.

An electric drill (can not be cordless, though) also works.

[NightWolve]

I think you would need to replace the automatic degaussing coil inside for it to permanently fix the problem, to keep up, but am not sure.

I had a TV that had this kind of problem: every time a pure white screen would be rendered, the deguassing couldn't keep up and the upper right section would start turning green. The TV would need to go black in that area for it to return to normal. To keep it from happening again, you'd need to keep the brightness and contrast down, but that would ruin the great, sharp picture this Samsung 27" had.

I made the mistake of buying an external degaussing coil and moving it around the affected area and all over, etc. but that could never fix it... The automatic degaussing would fix it when it got a break from a white screen in that area, but yeah, it was recurring thing. My thought was perhaps a newer, slightly stronger coil being replaced inside might fix it, but I wouldn't have ever felt confident to do that kind of replacement back then. As I eventually upgraded to another TV, it didn't matter then, but I wasted my money on that external coil...

[cjameslv]

I think you would need to replace the automatic degaussing coil inside for it to permanently fix the problem, to keep up, but am not sure.

I had a TV that had this kind of problem: every time a pure white screen would be rendered, the deguassing couldn't keep up and the upper right section would start turning green. The TV would need to go black in that area for it to return to normal. To keep it from happening again, you'd need to keep the brightness and contrast down, but that would ruin the great, sharp picture this Samsung 27" had.

I made the mistake of buying an external degaussing coil and moving it around the affected area and all over, etc. but that could never fix it... The automatic degaussing would fix it when it got a break from a white screen in that area, but yeah, it was recurring thing. My thought was perhaps a newer, slightly stronger coil being replaced inside might fix it, but I wouldn't have ever felt confident to do that kind of replacement back then. As I eventually upgraded to another TV, it didn't matter then, but I wasted my money on that external coil...

Ya my normal advice be to throw it away and go get another one off craigslist for 20-30 bucks.  But im not sure what the crt market is like in japan?  Or if there is a craigslist there even lol

[thesteve]

that is a text book degaussing issue
in response to 1 of your earlier responses the degausing coil is only active for a moment on power up as it causes picture disturbances

[ClodBuster]

+1 to what Steve said.

I guess the quick-and-dirty fridge magnet fix could do it, but I would like to hear input on that from a more experienced person than me. One thing that puzzles me is that I found such colour issues way more often on CRT-TVs than on CRT monitors for computers.

[Necromancer]

Take a hair dryer and......

Bernie? 

[cjameslv]

Take a hair dryer and......

Bernie? 

Hey it's a solid plan!

[Fidde_se]

There is a very good fix, but we have to travel back in time, lets take a walk down memory lane shall we....

You have a permanent magnetic damage that's temporarily, yeah that's right, it's permanent until you fix it, so it's temporarily then... this is why surround speakers are magnetically shielded, well this you already know, lets move on...

Back to the days of professional tape, reel to reel and vinyl, as the magnetic tape swirled by the tape heads the metal in the heads became magnetic themselves, heads had to be cotton swabbed and defluxed, by a defluxer, comes in many shapes, can both demagnetize and magnetize metal depending on if you start it close to the object and moves away or the opposite. the defluxer has since been forgotten, some audiophile firms still make them, some are pricey, a couple hundred bucks more then you would even consider spending... some times found cheap at flee markets and garage sales, 70-80ish HiFi has started to come around again and luckily the Chinese has cought a sniff of these things, so for the 20th of the price you can get this
http://www.ebay.com/itm/Cassette-Tape-Recorder-Reel-to-Head-Demagnetizer-Akai-/400527079402?pt=Vintage_Electronics_R2&hash=item5d414637ea

Using a magnet doesn't work so good as the magnetic poles is not controllable as a defluxer where it's concentrated.

Has helped me fixed dozen of TV's where this has happened, just use with some patience.

[thesteve]

that a NOS listing, that thing is from the 70s-80s
degaussing wand is the same thing only bigger

[SamIAm]

Thanks for all the replies!

Take a hair dryer and rub the back part (air intake side) about 1/2" away from scren in swipe motions. kinda like your wiping the discoloration away. It can take a few min to get it. I have had fair success with this on my arcade monitors so i think this would work for crt tvs as well.

You know, I tried that earlier, and it didn't seem to do much. I can try it again, though. It seems like there's a permanent magnet in the motor, because it causes a reaction even when the dryer isn't on.

An electric drill (can not be cordless, though) also works.

Thanks. I read about that, too, but I sadly don't have one of those.

I had a TV that had this kind of problem: every time a pure white screen would be rendered, the deguassing couldn't keep up and the upper right section would start turning green. The TV would need to go black in that area for it to return to normal. To keep it from happening again, you'd need to keep the brightness and contrast down, but that would ruin the great, sharp picture this Samsung 27" had.

I've had that with another TV. I think it was a Panasonic. It would go brown on the left and drive me crazy. I also have a Toshiba set which does it just a little, but only when the TV is on its side for tate shooters.

that is a text book degaussing issue

Awesome. That's what I thought. Thanks a lot for your input.

So, the challenge for me is just how to degauss it. I live in Japan, and the degaussing tools on amazon.jp are like $70. Further thoughts below.

+1 to what Steve said.

I guess the quick-and-dirty fridge magnet fix could do it, but I would like to hear input on that from a more experienced person than me. One thing that puzzles me is that I found such colour issues way more often on CRT-TVs than on CRT monitors for computers.

Computer CRT monitors apparently have a much stronger degaussing coil built-in. In fact, one crazy fix for degaussing a TV that I have read about is to hold a monitor up close to the TV and turn it on there.

70-80ish HiFi has started to come around again and luckily the Chinese has cought a sniff of these things, so for the 20th of the price you can get this
http://www.ebay.com/itm/Cassette-Tape-Recorder-Reel-to-Head-Demagnetizer-Akai-/400527079402?pt=Vintage_Electronics_R2&hash=item5d414637ea

Using a magnet doesn't work so good as the magnetic poles is not controllable as a defluxer where it's concentrated.

Has helped me fixed dozen of TV's where this has happened, just use with some patience.

That looks nice. The price is a little closer to something I can accept, that's for sure.

http://www.aliexpress.com/item/CRT-TV-TV-degaussing-degaussing-wand-color-display-demagnetisers-0-8-kg/1853319656.html
How about this thing? I mean, it looks about as suspicious as a cheap Chinese product can look, but if degaussing wands are as structurally simple as I suspect they are, then maybe it would work anyway?

The last option would be to build a coil myself. Believe it or not, there are lots of places just like dollar-stores in Japan, and in one store, I can get a plug, cord, copper wire, electrical tape and a switch for less than $10 total. If I build in a light bulb for resistance like in this design, I think I can keep my house from burning down.

Any thoughts?

[thesteve]

That design is fine, a ceramic or film cap from the horizontal circuit can be used as well for limiting the current
Such a cap can be added to the monitor as well for continuous degaussing without much effect on the image