Is This Tube Permanently Damaged?

[bungy]

This tube won't seem to completely degauss. I have used a ring degausser, but the result is always the same, the two spots near the middle are always discolored. I've read that the shadow mask can become bent or permanently magnetized. Is that what has happened here?

 

[splattergatz]

could be the mask has 2 bubbles in it and is in the process of seperating from the inside tube face

 

[ggames]

You have a static problem or a light problem. No big deal. You will probably notice a difference by moving the game to a different area even if it's 4 inches away. Fluorescent bulbs are a frequent menace.

 

[bungy]

What a wonderful thing to happen to an Amplifone tube

could be the mask has 2 bubbles in it and is in the process of seperating from the inside tube face

 

[bungy]

Some more pictures of this phenomenon. I can even see it while I'm using the manual degausser.

 

[THE COUNT]

Going by your last set of pictures and the fact that you can see it while manually degaussing, I'd say that is a tube issue that will not be fixable. If it was a degaussing issue, it would be corrected or at least changed signifigantly while manually degaussing. If that was happening around just the edge, it could be a magnetized frame issue, but this is also not the case here.

 

[kentmurphy]

man that's a bummer ...

 

[cadillacman]

that sucks!..

have you tried moving the yoke around/in-out/moving wedges? ****MARK EVERYTHING FIRST!!!********

I have seen a monitor dropped HARD before and the mask inside did get bent permanently. No matter what i did i couldnt get it out, but that was in a corner, not in the middle like this one..

Was this a nos tube you put in? if so, mabye it got sropped during shipping, or HOPEFULLY you just dont have something adjusted right.

pm mark h and see if he has any advise...


best of luck man.

 

[DogP]

From the shape and color, it looks almost like someone took a strong permanent magnet and put it up to the face of the tube. It may be worth trying to use a permanent magnet turned the other direction to possibly demagnetize/remagnetize, and try slowly moving it around the affected area. Then use a degaussing coil to undo anything caused by your permanent magnet.

DogP

 

[mikerk]

That tube was definetly dropped and permanently damaged

 

[DogP]

That tube was definetly dropped and permanently damaged

I disagree... that looks much more like a magnetic problem than being dropped. Note the shape and opposite polarity, and how it starts from the middle and expands outward. That looks like someone took a simple two pole magnet to it (possibly a pretty strong one).

DogP

 

[bungy]

It is a Rauland M48AAW00X, not NOS - has a couple tiny burn holes in the center. The tube doesn't look like it has been dropped as there is no visible damage on the outside. That's not to say it hasn't been dropped, but I haven't dropped it and I don't see any physical evidence of a drop. Can this just randomly happen to to a tube?

I have a few very big (2"x2"x1") rare earth magnets but they were not able to change the problem. I tried moving the tube around and mussing with the yoke, but nothing can fix or change it. That blue spot between the two discolored patches does not look natural at all, it looks even more weird in person than in the pictures. I'm starting to accept that the tube is toast.

 

[mikerk]

Ive been through this several times, when the tube is dropped or struck hard enough it will look exactly the pictures. Ive seen this also right after the tube is turned off, but not while its on and it looks like a pretty aurora. And no, I am not confusing flyback discharge with this either. That little blue spot in the center between the big blue spot and the yellow/green is the point of impact.

So if it is magnetism and a coil will not remove it whats next?

 

[bungy]

I used the big magnet again tonight and it might have helped one of the patches a little bit. It can still be seen on the Star Wars logo (blue becomes red), but is now a lot less noticeable when the instruction screen comes up (red stays mostly red instead of going green).

While I was using the magnet, I could hear metallic echos inside the tube while I moved it along the tube face. As I moved the magnet closer, the patches became uniformly distorted with the surrounding areas. But the blue "spot" between them held the same shape and features as I moved the magnet.

I have a hard time believing that being struck on that point caused the problem. The glass is perfect. It almost looks as if the inner shadow mask was mangled with pliers from the inside somehow. There is some slight "dot burn" in that area too. Not real dot burn like the center, but it looks like an electron beam may have been focused there for a period of time. I wonder if that could cause this problem in any way.

If I'm feeling saucy later, I may take a video of the tube's reaction to the magnet to illustrate.

 

[bungy]

Here is what happens when I use a magnet with the tube:

 

[cadillacman]

man thats cool. Sorry to say, that tubes toasty.. keep playing, mabye youll accidentally fix it.

 

[DogP]

Yeah, that looks pretty screwed. I see there's a discontinuity in how the colors roll across the screen when hit with the magnet around those discolored areas... that seems like a dead giveaway that there's a more serious problem .

DogP

 

[skforty]

I don't know about the type of magnet you are using in that video, but i have seen shadow masks perm messed up with very strong magnets before or ive seen the resulting damage i should say.

Also try using smaller, but still powerful magnets on the rear of the tube, not the face to see if you can improve the problem.

 

[bungy]

The damage was there before I tried the magnet. I started with a smaller one, and moved up to bigger ones when there was no change. I'll try from the rear, but I'm pretty certain this problem can't be fixed.

 

[skforty]

oh i wasnt implying that you caused the damage, i was saying 2 things with that statement;

1) Its a good idea to be careful when using strong magnets on CRTS because it is possible to cause damage
2) Even though didnt see sign of physical damage to the monitor, that is a way ive seen monitors damaged and might have (although unlikely) been what caused the damage to your monitor.

Most of the time though, the shadow masks get bent or damaged when a cab gets tipped over or something. The monitor shows no damage , but a tweak of the monitor frame etc can cause it.

Anyway, good luck.