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monitor problem

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samcheetah

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i have an LG Studioworks 452V and im having some problems with it. in the beginning it was a small problem. sometimes i noticed that for no reason the screen became dark. after a light tap on the monitor's side the display became normal. this continued for a couple of weeks. i figured that it was due to some bad solder joint so it wasnt such a big problem.

but then one day i turned on the monitor and the screen was all colorfull. at first i thought that i might have changed the wallpaper but then i noticed that there was some problem with the monitor. the colors on the edges were all mixed up; blue became green, red became purple and so on. but this was only on the edges. and one thing more, the pattern looked like it was because of the speakers that are placed with the monitor. the speakers that i have are zoltrix ZX-75 and are placed 1.5 feet away from the mointor. the reason i think that the pattern is because of the speakers is that my headphones are on one of the speakers. and the pattern on that side is bigger than the pattern on the other side.

well my question is that what is this problem. and is it repairable or do i have to get a new monitor?
 
The problem you're describing is called a "purity error", where the colours become mixed up due to an offset of the magnetic field on the CRT. This effects the tradjectory of the beams and so what was supposed to be red comes out as blue and so on.

Inside the monitor itself you've got a "deagussing" circuit which basically neutralises any unwanted magnetic field surrounding the CRT. If this circuit is not functioning correctly, you can end up with a purity error. You can also end up with a permanent purity error if the CRT has been damaged due to the monitor being dropped. Some monitors have a manual degauss function which you can initiate while it's switched on. If yours has that option, try setting it off while you've got the monitor on and see if the purity error clears. If not you've either got a faulty CRT, or the degauss circuit is not functioning properly, either due to dry joints somewhere or a faulty positor.

If the purity error cleared when you asked the monitor to degauss, the problem was most likely caused by you sitting the speakers too near the monitor.

Brian
 
ThermalRunaway said:
The problem you're describing is called a "purity error", where the colours become mixed up due to an offset of the magnetic field on the CRT. This effects the tradjectory of the beams and so what was supposed to be red comes out as blue and so on.

Inside the monitor itself you've got a "deagussing" circuit which basically neutralises any unwanted magnetic field surrounding the CRT. If this circuit is not functioning correctly, you can end up with a purity error. You can also end up with a permanent purity error if the CRT has been damaged due to the monitor being dropped. Some monitors have a manual degauss function which you can initiate while it's switched on. If yours has that option, try setting it off while you've got the monitor on and see if the purity error clears. If not you've either got a faulty CRT, or the degauss circuit is not functioning properly, either due to dry joints somewhere or a faulty positor.

If the purity error cleared when you asked the monitor to degauss, the problem was most likely caused by you sitting the speakers too near the monitor.

Brian

Hi Brian
I have experienced this kind of problem too. They occur frequently when I switch on and off my monitor(not on stand by) may times during the day. Typically due to frequent power cuts/low voltage , I need to switch on/off my monitor many times..SO can this be a voltage related problem in the sense that the Tubes do not get the right voltage to fire ?
 
Elektrix, I'm not quite sure what you're asking me. I think you're saying that you too get purity problems with your monitor and, the only way you can seem to get rid of the symptom is to switch your monitor off/on/off/on many times - is this correct or have I misunderstood?

Brian
 
thanx ThermalRunaway for telling me what the problem is. as far as i know my monitor doesnt have any manual degauss function. now i know what the problem is so im confident in going to the repairs shop.

and Electrix i dont have such a problem that you have described. but it might have caused the problem in the first place.
 
samcheetah said:
i have an LG Studioworks 452V and im having some problems with it. in the beginning it was a small problem. sometimes i noticed that for no reason the screen became dark. after a light tap on the monitor's side the display became normal. this continued for a couple of weeks. i figured that it was due to some bad solder joint so it wasnt such a big problem.

Hi Samcheetah,
The problem you describe may be a degaussing problem, but also a general failure in the high voltage generation. You say the the screen went dark a few times, this may indicate that your high voltage generator is on the edge of failure. If the voltage drop some you will see this as a reduction in size of the picture. The electron beams will also loose energy and the weak magnetic field from your speakers could the be powerful enough to interfere.

You could see this by moving the speakers further away from the crt. If the picture change to the better it may indicate a voltage problem.

If the picture is still scrambled you need to turn the monitor off and on again to degauss it. Normally you hear this as a 'boing' sound after power on. This will normalise the magnetism in the grid mask behind the screen.

TOK ;)
 
Just one thing: when the first degaussing (by switching ON) is not successfull, sw OFF, and wait minimum 10min for PTC cooling before sw on again.
 
the color effects that i am seeing right now seem to be permanent. i have tried moving away the speakers and then turning on the monitor but there is no difference at all. could this mean that there has been some permanent non-repairable damage to the monitor????
 
ThermalRunaway said:
Elektrix, I'm not quite sure what you're asking me. I think you're saying that you too get purity problems with your monitor and, the only way you can seem to get rid of the symptom is to switch your monitor off/on/off/on many times - is this correct or have I misunderstood?

Brian

Brian, I think I was not clear. What I meant was, I experinece this kinda problem whenever there are frequent periods of switching on and off. Say in an hour if my monitor has been turned on/off about 15 times..I get the problem on my screen. I think that due to rapid changes in potentials inside the CRT, something goes wrong.
 
Electrix said:
Brian, I think I was not clear. What I meant was, I experinece this kinda problem whenever there are frequent periods of switching on and off. Say in an hour if my monitor has been turned on/off about 15 times..I get the problem on my screen. I think that due to rapid changes in potentials inside the CRT, something goes wrong.

It's quite possible that the posistor in your monitor is faulty, or has a dry joint on one of the pins. Both are very common faults, and you can usually 'test' a posistor by removing it and giving it a shake - if it rattles, then it's faulty.
 
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