[Tfug] dell 8100 dim screen (was: anybody have a laptop video card?)

[Adrian]

On Friday 10 June 2005 05:18, t takahashi wrote:
> i noticed that when it goes black, it isn't really black, just very dim.
> 
> so it might be the backlight or inverter or cable or something.  not just
> video card or drivers.  sorry for jumping the gun on the diagnosis.
> 
> anybody know a way to diagnose it/take it apart, or failing that, a good and
> very cheap repair place in town?
> 

Depends... If it starts bright, and the screen looks good, but then goes dim, 
I would rule out both the backlight and the video card. The bright initial 
display indicates a good backlight. For the video, a simple test would be to 
plug a monitor into the laptop after the LCD has gone dim... If the monitor 
displays fine then your video card is fine.

From the sounds of it, I would suspect that the inverter is bad. Most likely a 
hairline crack in the PCB (probably in the boost circuit) that opens up as 
the laptop warms up... The inverter board will be at the top of the laptop, 
between the LCD hinges, either in the LCD panel itself or in the base unit. 
Dell has good PDF service manuals that give a complete parts breakdown 
(though they really hide them these days).

After you've done the monitor check, if the inverter is in the base, 
disassemble the laptop by removing the keyboard (4-5 screw thru the bottom), 
then pop then keyboard out. Next pop the plastic cover above the keyboard out 
(varies between modules). Underneath should be the inverter, pull it out and 
check it for defects, reseat, test again... A new inverter can be had pretty 
cheap on Ebay.

Adrian