01-02-2010 03:45 PM - edited 01-02-2010 03:46 PM
a couple of weeks ago my one year old laptop was running perfectly when the screen suddenly blanked out/crashed and no matter what i did, the screen wouldn't light up again...
i connected my laptop to an external moniter and it worked perfectly so i know there's nothing wrong with the hardrives. also, when it was connected, it didn't have a pink hue like other ppl said--
so here's my question (after stalking various forums, i have come to a conclusion)
- is there something wrong with the inverter?
- or is it just the backlight that has exploded?
i really appreciate any suggestions because i miss my computer (and i need it badly for school ><)
Solved! Go to Solution.
01-02-2010 07:16 PM
Welcome to the forum.
If you look at the screen very carefully while your laptop (T500?) is on, can you see very faint text and graphics still being displayed? If you shine a flashlight on it at just the right angle, sometimes you can see this. The cause is that the LCD is still working but the backlight is no longer projecting light through it for you to see. Either the inverter or the backlight (or maybe both) has failed. Sorry I don't know of a test to determine which. But the inverter is much cheaper and easier to replace than the backlight. I'm not sure if the backlight can be replaced independently of the LCD -- usually they are removed/installed as a unit.
Some T400/T500's use an LED instead of a fluorescent backlight. If you post your machine's model number, 7 digits XXXX-YYY from the label on bottom, in many cases that will indicate which screen you have. If it's an LED backlight model, there's not an inverter per se, but I think there's still some driving circuitry that goes in the same place behind the green status lights on the lower right bezel. (I don't have experience with those models.)
What I should have asked first: Is your ThinkPad still under warranty?
01-03-2010 05:24 AM
Either the inverter or the backlight (or maybe both) has failed. Sorry I don't know of a test to determine which.
Here is a thread that says since you didn't see a red screen before it went black, it's your inverter that has failed, not your backlight.
01-03-2010 03:30 PM
ugh, i think i've posted this in the wrong place since mine is a SL400, but thanks for the quick reply! ><
with regards to what u said before, the torchlight thing worked so i could still see the beginning welcome sign and everything...
i looked at the thread link u posted but it doesn't really address my issue since his problem is the CCFL...
if it isn't a bother, could you find a way to know for sure if it's either the inverter or the backlight that's causing all the trouble??
THANKS A BUNCH!!!!
01-03-2010 03:38 PM
Because you never noticed the pink/red hue, it's probably the inverter.
01-21-2010 05:28 PM
uh oh... bad news
the inverter i ordered came today and i was all psyched and hyped up but when i put the new one in, the screen was still dark...
so i guess it's not the inverter huh?
any other suggestions would be greatly appreciated
01-21-2010 06:21 PM - edited 01-23-2010 04:19 AM
Bummer that the new inverter didn't fix it.
When I replaced the screen on an R61, I had to remove and then re-install the inverter. The first time I powered up with the new screen there was no backlight. It turned out that I'd failed to push the screen's backlight connector all the way onto the inverter connector. You might just double-check that connection to be sure.
But it seems likely that your screen's backlight has failed. I've read of people replacing just the backlight instead of the entire screen, but I think it's a delicate operation. You could try searching for others who've done it and decide if it's something you'd like to try. Maybe there are companies that replace LCD backlights (I'm not aware of any).
Otherwise, you're looking at replacing the entire LCD. You can do this yourself if you like, if you exercise some care and patience. But you must be sure to get the exact LCD replacement - the connector pinout isn't standardized like (say) an SATA connector. The Hardware Maintenance Manual (HMM) will have the LCD part number you need; you'll also find it on a label on your current LCD. The HMM also has instructions for replacing the LCD, and you can watch a video at:
You don't have to follow the HMM's exact method to remove the LCD. For instance, you don't have to completely remove the lid assembly from the base. But it's still helpful to see ahead of time how the parts fit together. I'd recommend putting sets of screws in little ziploc bags as you remove them, and put in a post-it note or other scrap of paper that describes where the screws go. If you have a digicam you can take pictures as you disassemble things, too. The idea is to wind up with no spare parts when you're done.
I've found that an old credit card can be used where the video calls for a "plastic probe", to separate plastic parts like the screen bezel without marring them; go slowly. And if you wear rubber gloves while installing your new LCD you can avoid getting your fingerprints all over it.
01-23-2010 04:33 AM
It occurred to me this morning that a broken LCD ribbon cable, or a poor connection where it plugs into the system board, could also cause the backlight to go out. It's not the most likely cause, because most times a failing ribbon cable would probably also cause screen corruption and/or led indicator light malfunction that you'd likely have noticed. But you might just have a look a the ribbon cable: You could try unplugging and re-plugging it into the system board, in case the connectors have become loose or oxidized. You could also give it a close visual inspection: look for kinks, pinches, broken traces. Just something else to check; if you find a problem with the cable, it is far less expensive to replace than the LCD. (Don't know about LCD backlight alone.)