The laptop boots, but the screen is much too dim to be seen. It is a Dell Precision.

precision m90 LAPTOP PC. 14 years old came with XP.


the screen is dead , does the monitor work on other PC?

fans in PC spin , heard or seen.?
step on ALL LAPTOPS remove the now very very old big battery now and test the LAPTOP with only the AC power pack as power.
work now/ ? yes, then buy a new battery.

next is the RTC coin cell ,none last 14 years either .

It sounsd like your GPU may be BGA chip and would require a re-flow/re-ball if your laptop shows graphical distortion on both monitors.

However I would first try taking the laptop apart again and double check you have connected everything properly.

boot to the BIOS (F2 at boot) and ensure that the LCD brightness is set to 8 and then reboot, if LCD is still dim, then, check the Control point system manager display settings and see if the LCD is dimmed there.
If no change, run diags Power + D at boot to run the LCD BIST test , if the 4 colored screens are DIM during the test, then the LCD has failed and needs repplacement.

Graphics card and possibly the LCD are bad, Replace as such.

try this press and hold Fn then tap on arrow up key check if the display will become bright. if fails try connecting an external monitor to your laptop check if display is fine. if not then uninstall video driver then install a latest one. if fails replace the video card drive or motherboard if video is built-in. if display is fine from the external monitor then reseat the LCD cable if fails then replace the LCD panel with the LCD cable.

when you boot the system hit the F2 key when the manufacturers logo pops up to log into the BIOS setup and look for the password screen and disable it.

Connect an external monitor to your laptop and power it up, if you see the normal Windows images then the video card and laptop is OK and the problem is definitely the backlight.

If you see a very dim image or black screen or flicking image on the LCD screen it means you have a backlight problem.

The buzzing sound is most likely the inverter problem.

Dim image and/or dark display on the laptop's LCD screen indicates a faulty LCD backlight and it could be the inverter that supplies high voltage to the CCFL lamp or it is the CCLF lamp is nearly burnt out or burnt out, most likely this is the case.
The inverter can be replaced easily but the CCLF lamp is more time consuming and requires soldering skills.
Check out www.lcdparts.net for parts, repair service and DIY info.

Try reseating the processor. Go to Dell.com and download repair manual. I have seen this same 3 lights a couple of times on c840's (same machine) when I forgot to lock the processor cam in place...

There’s probably an issue with your boot-up files or the hard drive. Suggest you start backing up all your documents, pictures and anything else that you don’t want to lose. Press and hold the <Fn> key while powering the system on. This will run the Dell Diagnostics. If no errors are detected, your software has a problem.



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That would be the backlight. If it were an inverter issue then you wouldn't have any video at all.

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