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bradoesch · Aug 27, 2003, 11:10 PM

I was playing with some pretty strong magnets with a computer monitor today and I think I went too far. The monitor won't go back to normal, ie there are still funny colors on the screen. I guess I put the magnets too close this time. I'd try deguassing it if I knew how. There's no OSD to deguass, just the screen adjustment buttons on the front. This is my parent's computer and I don't want to buy them a new monitor. :/ The monitor is an IBM G40, if that helps. 14" shadow mask, 1995 ish. Hopefully somebody can help me,

Brad

calimehtar · Aug 27, 2003, 11:17 PM

I think these things fix themselves, or at least improve, with time. I say don't worry about it too much for now.

bradoesch · Aug 27, 2003, 11:26 PM

Originally posted by calimehtar:
I think these things fix themselves, or at least improve, with time. I say don't worry about it too much for now.

I hope you're right. This monitor has seen better days though. It's also doing a funny thing where anywhere there's dark colors there's a white strip following it to the right. For instantance, the blue bar that's all over these forums always has a white "tail" on the right of it, right to the end of the screen. My iMac DV has started doing this too, but I don't want to get into that.

tr · Aug 28, 2003, 01:58 AM

there might be a degaussing button on the back of the monitor. i'd check that first. also, some monitors automatically degauss after being turned off/unplugged then powered up again.

according to this pdf:

http://www.asso.pl/magazyn/dokumentacja/mwbook.pdf

the G40 has a 'power switch only' degauss button. try turning the monitor on and off, or holding the button when turning it on. that might help.

if anything, you can probably take it to a tv repair shop, and they can degauss it for you. most likely, tv repair shops have external degaussing coils.

tr

clarkgoble · Aug 28, 2003, 07:17 PM

Umm. Isn't the monitor the least of your worries if you had a powerful magnet? I'd be worried about the reliability of your data on the HDs. Hopefully the system was far away from the monitor and more importantly the magnets.

bradoesch · Aug 29, 2003, 09:03 AM

Originally posted by tr:
there might be a degaussing button on the back of the monitor. i'd check that first. also, some monitors automatically degauss after being turned off/unplugged then powered up again.

according to this pdf:

http://www.asso.pl/magazyn/dokumentacja/mwbook.pdf

the G40 has a 'power switch only' degauss button. try turning the monitor on and off, or holding the button when turning it on. that might help.

if anything, you can probably take it to a tv repair shop, and they can degauss it for you. most likely, tv repair shops have external degaussing coils.

tr

Thanks for the link. I've never been able to find detailed information about this monitor before. I've certainly looked though, when I put Linux on that machine a few years ago I had to find the the vertical and horizontal frequencies, etc.
I tried holding the power button on when turing the monitor on but nothing happened. I wish that PDF explained it a little better than that. The way it describes turning on and off DDI support is lacking too, it says you do it by holding a button while turning the monitor on. How are you supposed to figure out it's the keystone button (or whichever one it actually is, I forget.)
I think might take it to the local TV shop in the next village and get them to degauss it for me.

bradoesch · Aug 29, 2003, 09:05 AM

Originally posted by clarkgoble:
Umm. Isn't the monitor the least of your worries if you had a powerful magnet? I'd be worried about the reliability of your data on the HDs. Hopefully the system was far away from the monitor and more importantly the magnets.

I don't think the magents were that powerful to erase the HD while they were in front of the monitor. Even so, a working monitor is more important than the information on the HD. It needs a format anyway, it's been almost 6 months.

alligator · Aug 29, 2003, 01:17 PM

I've had some success with one of the "gun" type soldering irons to degauss a monitor. Hold the soldering iron a few inches away from the screen, and the rapid switching of the current in the soldering iron must create an alternating magnetic field which helps erase this effect.

clarkgoble · Aug 30, 2003, 12:51 AM

I didn't think they'd erase the HD. However what if they just screwed up a few bytes here or there? Or made it so read/writes became slightly unpredictable? That is almost worse than an erased disk because it appears like it is working when it isn't.

geekwagon · Aug 30, 2003, 01:02 AM

If you can leave it off for a while, these things almost always fix themselves (over a few days.)

bradoesch · Aug 30, 2003, 02:39 AM

Originally posted by alligator:
I've had some success with one of the "gun" type soldering irons to degauss a monitor. Hold the soldering iron a few inches away from the screen, and the rapid switching of the current in the soldering iron must create an alternating magnetic field which helps erase this effect.

There's a "gun" soldering iron around here. I'll try that if it doesn't clear up itself.

bradoesch · Aug 30, 2003, 02:42 AM

Originally posted by clarkgoble:
I didn't think they'd erase the HD. However what if they just screwed up a few bytes here or there? Or made it so read/writes became slightly unpredictable? That is almost worse than an erased disk because it appears like it is working when it isn't.

Actually I wouldn't mind if those magnets would've screwed the entire computer. It's the computer my parents use, and they've said their next one is going to be a Mac. They notice that it needs formatting at least twice a year and how bad Windows 98 is while my Mac runs great.

bradoesch · Aug 30, 2003, 02:43 AM

Originally posted by geekwagon:
If you can leave it off for a while, these things almost always fix themselves (over a few days.)

I think it's been getting better. It could use a degauss anyway, it's very, very blurry. :/

reynard · Aug 30, 2003, 03:40 AM

I just want to add to those saying that monitors that have suffered this fate do tend to cure themselves.

Also, a bit of trivia. Regarding magnets and hard drives: Certainly a magnet held too close to the actual hard disk would reek havoc. But did you know that there already are extremely powerful magnets within centimeters of your hard disk right now?

The little arm that floats over the spinning disk has powerful rare earth (neodymium) magnets near its base. I believe that these are magnets sense movements in this arm. The purpose would be to monitor the location of this arm.

I'm no engineer but it is ironic that hard disk drives depend on super powerful magnets--as long as they are placed strategically.

bradoesch · Aug 31, 2003, 10:30 PM

I love taking apart old hard drives and stealing their magents. I didn't realize they were neodymium magnets, interesting to know that. I've bought some rare earth magnets and were they ever powerful! I'd like to buy some large ones and really have fun with them.

tooki · Aug 31, 2003, 10:58 PM

I was gonna say... CRTs are MUCH, MUCH more sensitive to magnets than hard drives... in fact, I'd be much more worried about the magnets in a hard drive messing up a CRT! (This is also why computer speakers have to be magnetically shielded.)

tooki

reynard · Aug 31, 2003, 11:55 PM

I have what I think is the best source for rare earth magnets. Im having problems pasting putting links in my posts here but you can at least copy and paste it.
magnets

You can get the dangerously powerful magnets here. Im not using the word 'dangerously' figuratively. The most common danger is pinching a piece of skin between two bad-ass magnets. It hurts like hell and damages your tissue.

If you become the least bit absent minded or complacent when handling them, they seem to seize the opportunity to snap together. You will think they are alive. And evil.

But they are impressive. And you can use them around the house. I attach a lamp with a metal frame above my workspace in the garage when Im working on tiny stuff. And when I dont need it, just pull it off. We have a wall mount TV stand in the bedroom. But it only holds the VCR. To hold the cable box just put some neodymiums on the bottom of the VCR and stick the cable box to it.

Let me clarify, you only need moderately-sized ones for these applications. The big, evil ones...I dont know. Ive hid them away. I pull them out once in a while to do a demo for company but they scare me. Keep them away from kids.

They may not even sell the big ones any more unless you can convince them that you are competent and have a good excuse. E.g, science demo.

BTW, all DC motors where hi power in a small, light package is needed use rare earth (neodymium or samarium-cobalt) magnets. The Honda electric car, that Helios plane that flies using solar engery, expensive power tools, etc.

bradoesch · Sep 5, 2003, 02:20 PM

Thanks for the link reynard, interesting stuff.

Anyway, the monitor keeps getting better with time like you guys said it would. I wouldn't mind getting it degaussed anyway since it's gotten so blurry over the years. What do you guys think a local TV repair shop would charge for this?

Maflynn · Sep 5, 2003, 02:55 PM

We have ibm monitors here at work and some off them have the degaussing in the setup of the monitor, that is with in the menu that pops up and you can select contract, color, pin cushioning. If that monitor has the menu, scroll through and see if there's a deguassing option.

As for tv repair, I would estimate between $40 and $100. The process is simple so they would probably charge their normal diagnostic fee. Who know after you explain what you did (and after he stops laughing) he may cut you a deal.

good Luck
Mike