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LCD monitor problem!!! pls help

My LCD monitor (northgate) turns off after i turn it on. It just blinks brightly for half a second then turns very dark. It does not totally turn off, but its just very dark. If i look closely i can see my OS (windows). when i turn it off and on again, the same thing happens. It Turns on brightly for a second then turn very very dark afterthat. I tried to use another monitor and it works perfectly with the CPU. so it must be the LCD monitor. Remember it does not turn off it just goes very very dark you could hardly read the start button on windows. Thanks guys. appreciate the help. Im willing to open it up if any of you guys know how to. heheheh
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chicolonga
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chicolonga
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1 Solution
 
Lee W, MVPTechnology and Business Process AdvisorCommented:
Using the other monitor, check the refresh rate on the video card - through the Display Control Panel, Advanced Tab, Settings button.

Make sure it's set to 60 Hz.  LCD monitors work in a very narrow frequency range and problems like that are often due to the computer outputing the signal at the wrong frequency for the monitor.
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CRAKCommented:
leew is right: LCD monitors are relatively slow (refresh rates 60 - 75 Hz, only 60 on "oldies"). Using a higher compatible frequency (75 Hz) will not likely provide a better picture or ease your eyes.

You might experience the same thing if you run at a low compatibel frequency, but at a high resolution like 1600*1200 @ 60 Hz. Gain controle over your monitor by reducing to 800 * 600 @ 60 before start working your way up again. Don't forget to test the new settings every time you make a change.
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ccomleyCommented:
You don't say if this is a problem with a new monitor or a new problem with an old one. Has the monitor ever worked? On this computer?

Sounds like it is turning off the backlight, but NOT preventing the signal being displaued on the LCD, which makes me less sure the problem is with teh PC configuration. Do you have another computer you can try the monitor on?

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AlasdairMcLCommented:
sounds like the backlight or inverter is at fault on the monitor, most likely the inverter as you're getting a bit of light, meaning the backlight does work and hasn't "blown" so to speak.

Check the monitor on another PC, and see if you get the same - if so it's definitely the monitor at fault. If you don't have another PC to try it on, try disconnecting the monitor from the PC, and switching it on so you get a 'check signal' message or similar on screen. This will let you confirm fully that the issue is the monitor and not an incompatibility with the video card.

Contact the manufacturer for the service manual, as this should give schematics and reference voltages to check which part has failed.

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WatzmanCommented:

Your backlight is turning off.  This isn't a refresh problem or anything to do with anything in the computer, it's entirely in the monitor (the key is that the actual image is still present on the LCD panel, you just can't see it -- it's VERY dark -- because the panel backlight is out.

There are only 3 possible causes:

-Bad LCD inverter
-Bad CCFT lamps
-Bad power supply

The problem is more than 80% likely to be the inverter.  This is a small board that takes 12 or 24 volts and produces the high voltage (about 1,000 volts, give or take 400 volts) that is needed to run the CCFT lamps.  THE VOLTAGES PRODUCED BY THIS BOARD CAN BE LETHAL, so be VERY careful working with it.  There could be a failure of the input voltage to this board, usually 12 or 24 volts, but inverter failure is more likely.  As a practical matter, it's very unlikely that you will be able to repair the inverter.  And getting replacement inverters that are an exact match (both electrically, and mechanically (connectors, size/shape and mounting) is very difficult unless you can get one from the original manufacturer.  Repair is easy IF you can get the part.  Inverters typically cost between $30 and $75 or so when bought separately as parts.
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Lee W, MVPTechnology and Business Process AdvisorCommented:
The simplist solution is most often the right one.  To that end I have to disagree with Alasdair and Watzman.  While I wouldn't rule out their recommendations, I've never seen an inverter have problems like that or any backlight problems with any LCD (Of course, this IS possible, just that based on my experience, it's RARE).  Try the frequency issue - this I've seen on a number of occasions and usually solves the problem as described.
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chicolongaAuthor Commented:
for leew.... i dont think that its the frequency. coz if i turn it on without it connected to the PC it should display something like "no input" or something like that on the screen. But rather it still blinks brightly and then goes very dark again. Connected or not connected to the PC it still acts the same way. Im thinking watzmans answer is possible. but im still not sure. im still open to something which i dont need to put out cash or just a setting problem. thanks guys... really appreciate it. need more answers though.
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chicolongaAuthor Commented:
one more thing i also tried this on another computer the same thing happerns. it just blinks for a second. then goes dark. i think its a backlight problem coz you can see the display only very very dark. But why does it brighten up for a second and turns off after that? it means the backlight is not busted but some connection of some sort is messed up.... please help thanks....
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AlasdairMcLCommented:
It brightens up then goes dark after a second because the inverter is faulty. If it were a connection, it would most likely work very intermittently as opposed to doing exactly the same thing whenever you turn it on. The inverter powers the backlight, and we know that the backlight works because it comes on every time you first power the display on.

What should happen is that the inverter takes the input voltage (12 or 24V) and converts it to a higher voltage that stays constant for as long as you keep the monitor on. Instead what happens is that the voltage is spiking at this higher value, and then going back down to a lower level that is not enough to drive the backlight.

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