Question about Dell Inspiron 9400 Notebook

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Laptop inverter problem

My display turned dark although i could make out distinct images under torchlight. I replaced the inverter and now its working on ac power .

as soon as i turn to battery power the display again goes blank as it was with the faulty inverter. also the laptop display brightness control function keys don't work and i cant change the screen brightness

please help me i use a dell vostro 1500 laptop

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You have major problem here - the power regulator on the motherboard which regulates the line voltage down to 12V to feed the inverter, and battery voltage /up/ to 12V to do the same, is blown. I've seen this happen in HP laptops - line voltage to the inverter on mains power reads at 18.2-18.5V (which overloads the inverter), on battery it reads 10.5-11 (which won't fire the inverter). This is usually a sign of a bigger problem. Usually one that involves replacing the motherboard.

Posted on Jul 21, 2009

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SOURCE: laptop inverter problem

Sounds like the real problem is with the CCFL lamp to me. :(

Posted on Jan 15, 2009

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Screen is not lighting while laptop is running.


Hook a spare monitor to the video output on the back of the laptop, if okay it means the video card is working fine. The problem is a bad inverter board, "located under the LCD display" or the back light is defective behind the screen, "usually means a screen replacement"

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The backlight on my gateway m 6750 is out. i think it is the lidswitch but can't find it. can someone tell me where the switch is located on my laptop.thanks


Hi,
The LCD screen displays is dark/ dim (faint display that can be seen in sunlight or torchlight) because there is no backlight.
There are two parts responsible for lighting the display. First is the CCFL (Cold Cathode Florecent Lamp), which is the back light and the second is the Inverter board, which provides high voltage to the CCFL. Either of the parts can be faulty or in some rare cases both. But most likely it is the CCFL (Lamp). Its life is limited and depending upon how long it has been in use, you can have a better idea - if its the CCFL or Inverter.
(You can check it by connecting you PC with some external display, which would work fine). (Hence, the board/ graphics processor is OK. In case the graphics processor fails, there is no display at all on the external monitor).
The LCD display switch in inside the modern laptop and its function is that it completely shuts down the display (no light as well as image).
So, my advice is that you check the LCD display for replacement of CCFL. I have found a general link about CCFL replacement. Click here for detailed and graphical DIY instructions about LCD disassembly.
Make sure you take proper precaution while working inside LCD, as the inverter generates a very high voltage.
IF YOU ARE NOT EXPERIENCED WITH WORKING INSIDE SUCH ELECTRONIC COMPONENTS, I SUGGEST THAT YOU SEEK PROFESSIONAL ASSISTANCE FROM AUTHORISED SERVICE/ REPAIR CENTER FOR REPLACEMENT OF CCFL OR INVERTER.

Hope it helps! Good Luck!
CreativeTECH

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1 Answer

Screen blank


Look at the LCD screen very closely and check if you can see a faint image on the screen. It's possible that the LCD lid close switch stuck in the "closed" position and the back-light stays off even when you open the LCD screen or turn on the laptop. The switch turns off the back-light when you close the LCD display to save the laptop battery power.

If that didn't fix it then there are 3 things that could have gone wrong:

1. Video cable connection from inverter to LCD got loose. To check this, follow instructions from step 3 on how to open the LCD and check if cable is fitted properly.

2. The video inverter is faulty
The screen inverter failure is very similar to the back-light lamp failure. In both cases the screen gets very dark and the image on the screen becomes very faint, barely visible under a bright light. If it's still under warranty, take it for a replacement. You can replace this otherwise - you can find the inverter under the screen, follow the procedure described at point 3 to open up the screen.

3. The LCD monitor is faulty
If it works on an external monitor most likely the LCD is faulty and needs replacement. If it's still under warranty, take it for a replacement. If not, you can do it yourself, it's pretty easy. Remove the rubber covers on the side of the screen, unscrew the screws take the plastic cover off, disconnect the video inverter and put in the new LCD after you connect the video inverter to it.

Feb 09, 2011 | Dell Inspiron 1525 Notebook

1 Answer

My lcd does not display anything when turned on


Look at the LCD screen very closely and check if you can see a faint image on the screen. It's possible that the LCD lid close switch stuck in the "closed" position and the back-light stays off even when you open the LCD screen or turn on the laptop. The switch turns off the back-light when you close the LCD display to save the laptop battery power.

If that didn't fix it then there are 3 things that could have gone wrong:

1. Video cable connection from inverter to LCD got loose. To check this, follow instructions from step 3 on how to open the LCD and check if cable is fitted properly.

2. The video inverter is faulty
The screen inverter failure is very similar to the back-light lamp failure. In both cases the screen gets very dark and the image on the screen becomes very faint, barely visible under a bright light. If it's still under warranty, take it for a replacement. You can replace this otherwise - you can find the inverter under the screen, follow the procedure described at point 3 to open up the screen.

3. The LCD monitor is faulty
If it works on an external monitor most likely the LCD is faulty and needs replacement. If it's still under warranty, take it for a replacement. If not, you can do it yourself, it's pretty easy. Remove the rubber covers on the side of the screen, unscrew the screws take the plastic cover off, disconnect the video inverter and put in the new LCD after you connect the video inverter to it.

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1 Answer

Compaq presario cq61 screen went dark but can still see window faintly through the dark sreen.


Look at the LCD screen very closely and check if you can see a faint image on the screen. It's possible that the LCD lid close switch stuck in the "closed" position and the back-light stays off even when you open the LCD screen or turn on the laptop. The switch turns off the back-light when you close the LCD display to save the laptop battery power.

If no luck, try to remove battery and drain the power, then replace battery and turn on.

If that didn't fix it then there are 3 things that could have gone wrong:

1. Video cable connection from inverter to LCD got loose. To check this, follow instructions from step 3 on how to open the LCD and check if cable is fitted properly.

2. The video inverter is faulty
The screen inverter failure is very similar to the back-light lamp failure. In both cases the screen gets very dark and the image on the screen becomes very faint, barely visible under a bright light. If it's still under warranty, take it for a replacement. You can replace this otherwise - you can find the inverter under the screen, follow the procedure described at point 3 to open up the screen.

3. The LCD monitor is faulty
If it works on an external monitor most likely the LCD is faulty and needs replacement. If it's still under warranty, take it for a replacement. If not, you can do it yourself, it's pretty easy. Remove the rubber covers on the side of the screen, unscrew the screws take the plastic cover off, disconnect the video inverter and put in the new LCD after you connect the video inverter to it.

Jan 06, 2011 | PC Laptops

1 Answer

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If the laptop acts as it would start and there's just no image, look at the LCD screen very closely and check if you can see a faint image on the screen. It's possible that the LCD lid close switch stuck in the "closed" position and the back-light stays off even when you open the LCD screen or turn on the laptop. The switch turns off the back-light when you close the LCD display to save the laptop battery power.

If that didn't fix it then there are 3 things that could have gone wrong:

1. Video cable connection from inverter to LCD got loose. To check this, follow instructions from step 3 on how to open the LCD and check if cable is fitted properly.

2. The video inverter is faulty
The screen inverter failure is very similar to the back-light lamp failure. In both cases the screen gets very dark and the image on the screen becomes very faint, barely visible under a bright light. If it's still under warranty, take it for a replacement. You can replace this otherwise - you can find the inverter under the screen, follow the procedure described at point 3 to open up the screen.

3. The LCD monitor is faulty
If it works on an external monitor most likely the LCD is faulty and needs replacement. If it's still under warranty, take it for a replacement. If not, you can do it yourself, it's pretty easy. Remove the rubber covers on the side of the screen, unscrew the screws take the plastic cover off, disconnect the video inverter and put in the new LCD after you connect the video inverter to it.

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1 Answer

My brightness control does not work just turned on and can not hardly see anything it is up and running what now


Have you tested it with an external monitor?

I would say you either have a damaged inverter board or screen baclight lamp. Usually the inverter board fails in one of the following ways:

1. When you turn on the laptop, the screen lights up for a short period of time and then goes dark. You still can see an image but it is very dark, almost invisible and definitely not usable. When you restart the laptop, the screen lights up and then goes dark again. The laptop works fine with an external monitor.
2. Your laptop turns on but the screen remains dark all the time. You still can see a very dim image outline. The laptop works fine with an external monitor.
3. The laptop screen works fine for hours or even days, but sometimes it goes very dark as it mentioned above. When you restart the laptop, the screen works fine again.

Inverter failure symptoms are very similar to backlight lamp failure symptoms and in most cases you cannot tell which one is causing the problem until you replace either the inverter board or the backlight lamp. From my personal experience, inverter boards fail more often than backlight lamps. If you have to guess, replace the inverter first.

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1 Answer

Blank screen


Look at the LCD screen very closely and check if you can see a faint image on the screen. It's possible that the LCD lid close switch stuck in the "closed" position and the back-light stays off even when you open the LCD screen or turn on the laptop. The switch turns off the back-light when you close the LCD display to save the laptop battery power.

If that didn't fix it then there are 3 things that could have gone wrong:

1. Video cable connection from inverter to LCD got loose. To check this, follow instructions from step 3 on how to open the LCD and check if cable is fitted properly.

2. The video inverter is faulty
The screen inverter failure is very similar to the back-light lamp failure. In both cases the screen gets very dark and the image on the screen becomes very faint, barely visible under a bright light. If it's still under warranty, take it for a replacement. You can replace this otherwise - you can find the inverter under the screen, follow the procedure described at point 3 to open up the screen.

3. The LCD monitor is faulty
If it works on an external monitor most likely the LCD is faulty and needs replacement. If it's still under warranty, take it for a replacement. If not, you can do it yourself, it's pretty easy. Remove the rubber covers on the side of the screen, unscrew the screws take the plastic cover off, disconnect the video inverter and put in the new LCD after you connect the video inverter to it.

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try to adjst the brightness and the contrast..

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Laptop inverter problem


Sounds like the real problem is with the CCFL lamp to me. :(

Jan 15, 2009 | Dell Vostro 1500 Notebook

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