Question about IBM ThinkPad R40 2681

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Screen darkens intermittently without command

My screen will black out at will. The black out is not total, I still can see a faint goast image, and the curser is still operational. Is this a battery issue, or is it time to saay goodbye to my trusty laptop?

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Re: Screen darkens intermittently without command

Sounds like your backlight is going bad.

Posted on Jan 06, 2008

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I have lenovo screen flickers in every 5minutes...

Failing Inverter An inverter, typically found inside a laptop computer, consists of a small board, which has impregnated electronic circuits stamped on it. Inverters look like thin boards about the of two sticks of chewing gum. The inverter and its bulb control the intensity of the liquid crystal display, which lights the screen monitor. The computer can control the output voltage of the inverter and either lighten or darken the screen. A special type of inverter can adjust the brightness of the screen by using an internal sensor to judge the room brightness, and then adjust the screen accordingly. Failing inverters give off some specific warning signs, which can be recognized by observing different screen characteristics.

Short Intermittent Display Upon turning on the laptop, the screen flashes on in the normal mode for a short period and then blinks to black. A very faint image appears in a dark background, which will be very hard to see almost invisible. After shutting off the laptop and restarting, the same mode occurs, where the screen appears normal for a few seconds then fades to black. This condition points to a failed inverter. To confirm this, plug in an operational external monitor; if the external monitor functions, the inverter has failed. b> Total Blackout with Ghost image b> The laptop turns on, as indicated by the power supply button, but the screen comes up black. The screen comes up black after restart. You might be able to detect a very dim or ghost-like image on the monitor. When you plug in a known functioning external monitor, the external monitor operates normally. This mode of display indicates a failed inverter. b> Long Term Periodic Operation b> With this failure mode, the laptop screen illuminates normally upon start-up and remains that way after several minutes, hours or even days, until it goes very dark again. Brightness controls or restoration attempts do not work. Most often, the screen will function normally with a computer restart, but will eventually return to black. Faint ghost images might appear, as seen in the total blackout mode. b> Dark With Color Variation b> Upon computer start-up, the monitor shows black or dark gray, accompanied by very faint images. The screen might have an intermittent color change, or remain on with a non-standard color variation, like pink or red. b> Auto Control Switch b> If the screen appears black, with no faint or ghost images, look for the lid switch near the back hinge. The switch, when depressed with a closed lid, shuts off the computer and monitor functions. Sometimes the switch becomes stuck in the closed position, disallowing the computer and monitor to turn on when opened. Pushing the switch manually several times can often free it up. If the switch tab has broken or jammed inside the case, it needs replacing. b> Loose Connection In this mode, the display looks normal upon start-up, but tapping the side case of the computer turns the screen black. More tapping results in the screen functioning normally then cutting out again. This condition points to a loose wire connection from the inverter to the LCD backlight lamp, or the video cable. The connectors can be accessed by removing the monitor bezel screws and pulling the plastic retainer off. Both connectors can be cleaned and refitted.

Feb 10, 2013 | Lenovo G550 PC Notebook

2 Answers

My acer laptop has nothing on the screen. I do have sound

First of all try removing the battery, unplugging from the mains and holding down the power button for 30 seconds. Reconnect the AC power adaptor ONLY and try again, if all works, reconnect battery

If this fails

Try plugging this into an external monitor see if you get a picture. You may need to press the FN and F5 F6 keys to toggle display.
If you do, then the problem is down to one of the following:
  • Inverter blown
  • Backlight damaged or not functioning
Take the laptop into a darkened room, if you can see a very faint image on the screen, the inverter is probably ok. If you see no image at all, the backlight has totally failed.

You will need to replace the inverter or screen, possibly (unlikely) both. To do this, removal of the screen is east enough with care, suggest you download a guide to dismantling the laptop or if not comfortable with doing this, take it to a technician to have this carried out.

If there is however, no image on an external monitor and you have tried the power off trick above, the fault lies in the graphics chip, which will need a qualified technician to look at.

Aug 02, 2011 | Acer Aspire AS7741Z-4633 Notebook

1 Answer

My laptop boots up but the screen is blacl

Try connecting the laptop to an external monitor first. If this works, you can eliminate the Graphics chip as a source of your problems.
If it fails to work on an external, the graphics chip on the motherboard has possibly gone bad.

If it does work, you have 3 possible problems:

  • The VGA cable has been damaged (unlikely)
  • The inverter has gone, you can check this by seeing if you can see a faint image on the screen in a darkened room, if you cannot, probably the inverter is at fault and will need replaced
  • The backlight has gone on the screen, if you CAN see a faint image, then the screen is getting power but the lamps are not lighting, you will need to replace the screen of the laptop.

Jul 20, 2011 | Acer PC Laptops

1 Answer

ACer Screen is pitch black, but system runs normally

Check if this will work on an external monitor, if it will, you can point the finger at the following:

  • Inverter failed: If you cannot see any image on the screen even a faint one, replace the inverter
  • Backlight gone: if you see a faint image on the screen, the screen needs replacing
  • Possible failure (unlikely) of the vga cable
If it will NOT work on an external monitor, the graphics chip on the motherboard has failed.

Jul 20, 2011 | Acer Aspire 55345410 Notebook

1 Answer

The computer indicates that it is on but cant see anything on the screen. Screen is still dark

Assuimed already that you have tried changing the brightness using the FN and F keys?
First, check the laptop gives an image on an extarnal monitor. If it does not, then your graphics chip has developed a fault
If it does, then the issue lies in the backlight having failed on the laptop screen, if you can see a VERY faint image in a darkened room on the screen, this mayalso indicate issues with the inverter. I suspect that you would need to replace the screen

Dec 31, 2010 | Toshiba PC Laptops

1 Answer

Acer Aspire 5100 Laptop Screen Works Intermittently

Since you have video with an external monitor your lcd panel is going out.This is not hard to repair only costly

Apr 06, 2010 | Acer Aspire 5100 Notebook

1 Answer

Black screen on my notebook gericom webgine xl per4mance??? The sistem is operating but can;t see anything!

Can you see any image in a darkened room - best to try right at start up when the logo appears. If you see a faint image it means your back light or inverter is out. OR it may be that the lid closed sensor switch is jammed which is telling the laptop to turn off the backlight. Look near bottom of the screen for a small bump sticking out - this will correspond to a switch on the laptop base. Make sure the switch moves up and down. Some switches are on the hinge itself.

Nov 18, 2009 | PC Laptops

1 Answer

My pc loads as normal but it is all sound and no picture

Try seeing a faint image in a darkened room - easiest right when you turn it on and the logo is appearing. If you see faint image it is possibly the backlight inverter. I have also seen one of these models where the lid switch was jammed. It is at the back right side and when the screen is closed it tells the laptop to go into standby which really just turns off the backlight. There should be a little stub sticking out or you may need to use tweezers to gently lift it back up. JC

Nov 12, 2009 | Acer Aspire 5500 5570-2609 Laptop

1 Answer

Laptop has power but screen remaining blank

Screen backlight/inverter may also be out - see if you can see a faint image in darkened room or by shining a flashlight into the screen

Apr 11, 2009 | Acer Aspire 5315 Notebook

1 Answer

It's all black

If you power it on, take a flashlight and shine it on the lcd at and angle and look real close to see if you can see a faint image. If you can, then your backlight in the screen is not working.
Also, you can attatch an external monitor to it, while its off, then power it on and see if it lights the external monitor. Try that and let me know your results.
If you get a picture ok on the external, and you can see a faint image on the lcd using a flashlight, then it could be the backlight inverter board or the bulb itself inside the lcd went out.
If you don't get any picture at all, using an external monitor and can't see a faint image on the lcd using a flashlight, then I would say there's other problems with the laptop itself. Could be a mainboard problem, power issue, etc..

Oct 24, 2007 | Compaq Presario X1000 Notebook

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