very strange problem with CRT TV

[Mame4All]

i use an old CRT tv for my classic gaming

noticed that after a few minutes of gaming on the TV i get some color smudges on screen which looks like magnetization to me

purplish on the left and brown on the right

but what the weird thing is its ONLY happens while gaming and by flicking the AV to a no signal channel is actually clears it up but once I go back to the game within minutes its back again, its not console related as it happens with all my consoles.

iv not tried it with TV stations but i assume it would be the same.

i dont have a clue whats going on, any help would be appreciated

Mame4All2015-04-17 05:03:27

 

[Hurray Banana]

Need to see some pics mate.

If it goes away when you have no signal then that will probably be because the guns aren't firing anything at the phosphor, so you wouldn't see any visual effect.

magnetic field of the earth will effect the tv as you rotate it 360 degrees so it might be that, like I said hard to tell without pics

 

[Mame4All]

hi mate heres 2 pics.

i dont have anything nearby that i would think would megnetize the TV.

only thing i dont know much about thats nearby is a Surge Protector but dont think thats got a magnet in it does it? lol

Mame4All2015-04-17 08:55:07

 

[virtvic]

Looks a similar problem that is also effecting the After a Burner at Arcade Club. I think RGP knows how to sort it.

 

[Hurray Banana]

does look a little like light magnetism.

 

[Dex-Jay]

Speakers causing it?

 

[Hurray Banana]

Speakers causing it?

good call, in the right areas

 

[big10p]

Yeah, I was thinking speakers, too.

 

[gunblade]

it could be capacitor related on the chassis
there does not seem to be any magnetic sources near enough to cause this

 

[tb2000]

Couldn't be the shielding on the speakers breaking down then?

 

[joe34]

hopefully it's not related to the example problem below, anyway here:
________________________

Question: Sony CRT TV Issue: Discoloration band up left side of screen. Won't clear with degaussing or adjustment of tabs

Answer: It would be helpful if you post an image of tv screen here to understand the problem properly, apparently it is purity problem that is related to aperture grille of picture tube and reason could be improper setting of Deflection Yoke mounted on picture tube neck or tv got hit hard with an object and aperture grille inside tube got misaligned (this is an irreparable problem and picture tube replacement is only option).

Answer: Thanks for tv picture, it shows purity problem and Yoke adjustment will minimize purity error. Loosen screw on yoke ring and slide yoke forward/backward a little to eliminate green bars in blue screen and then tighten yoke screw.

Question: Moving the yoke and adjusting the tabs only makes it worse. Loose shadow mask inside the tube?

Answer: If yoke adjustment makes purity worse then I'm afraid, it is a problem of disturbed shadow mask / aperture grille in tube and usually it happened when tv/tube got hit with something or dropped during transportation. picture tube needs to be replaced to solve tv problem.

 

[Bods]

With purity issues like it caused by magnetism.

Depends when it shows up. some colours show it worse than others, primary colours like red, blue will show it bad, if the screen is displaying bright white u may not see it

If you have moved the tv recently that could be it, two crts close together can affect them

Degauss circuit may be faulty

Speakers are made for the tv and distance is far enough away or they are shielded. Unless someone replaced the speakers

If crt has had bad knock it can move insides

My first jamma cab was strange. The crt was great picture and on most screens it looked perfect. I was running mame and thick it only showed on light blue screen when shutting down, it had a circle in middle of screen, quite faint but it was more like it was burnt into it, but perfect circle probably bigger than cd

Never seen that before. So can be few things.

 

[joe34]

just thinking out loud really but maybe a test to do to see if the 'smudges' on your screen are related to magnetism or not is, get the tv going with an all blue screen so you can see the smudges (like as in your second picture in your first post in this thread). now, keeping the tv on, if possible (ie. if it's not too heavy), try to rotate the tv onto its side (either side) so it is in the 'vertical' position instead of normal horizontal position.
while you are doing that, look carefully/closely at the screen and see if any of those smudged areas change in any way (eg. in colour, size, shape, position/movement, etc.. also: unlikely but still; listen for any odd sounds). report back the results here and perhaps that might give some more clues as to pinpointing your problem.

 

[Mame4All]

hi there. when tv is tilted to the right the brown smudge or the right side disappears and the left side purple is even more prenounced. iv actually just picked up a new TV and its still the same results. iv even used the TV in a different room and same thing happens

 

[Mame4All]

im not sure but the TV i just picked up today exhibits the exact same problem, even when used in different rooms etc

 

[virtvic]

It's haunted.

 

[Mame4All]

lol

 

[Mame4All]

i dont think the degaussing circuit is faulty because when its powered on from a cold boot the screen is perfect so i presume its doing its job. but then after a minute or so it starts to GRADUALLY work its way back to the smudges. weird
Mame4All2015-04-19 22:58:12

 

[joe34]

hmm, im half tempted to suggest, take it to a friends or neighbours house and try it there

 

[Hurray Banana]

hmm, im half tempted to suggest, take it to a friends or neighbours house and try it there

does seem like some strange magnetic field weirdness if this is the case, do what Joe says