trooper Posted March 7, 2006 Share Posted March 7, 2006 Hi Guys I've got a Fujitsu lap top and yesterday I switched it on to an almost blank screen. I can just about make out that it's working but no back-light. It's only six months old, can the light have busted so soon? or could it be a light stealing virus? Anyone else had this with theirs? :-( Link to comment Share on other sites More sharing options...
Ribenaberry Posted March 7, 2006 Share Posted March 7, 2006 Hi mate, Finally a question i can help with, (IT Helpdesk geek here!) I am not sure if your laptop would have one but it is possible that your brightness level has been adjusted way too low. So have a look at this. However if you don't remember adjusting it this low, which you probably don't hehe, then unfortunately it means that the screen is not getting enough power. Does it get brighter when you plug it into the power pack? Give it a full charge and if this makes no difference, you will have to return it to where you bought it if you have warranty. Dale Link to comment Share on other sites More sharing options...
trooper Posted March 7, 2006 Author Share Posted March 7, 2006 hmmm, I certainly haven't adjusted the brightness myself but I will check when I get home. As for the power, it's permanently plugged into the mains and hardly ever runs on the battery. Prognosis bad! It's only 6 months old and still in warrenty so I'll probably have to take it back to the shop. I just hate the thought of being without my PC! I must be addicted. Chineese rubbish! Link to comment Share on other sites More sharing options...
Ian R Posted March 7, 2006 Share Posted March 7, 2006 Same thing happened to my hp laptop had to replace the screen under warranty Link to comment Share on other sites More sharing options...
Burna Posted March 7, 2006 Share Posted March 7, 2006 Have you tried switching off and back on again? Link to comment Share on other sites More sharing options...
carl0s Posted March 7, 2006 Share Posted March 7, 2006 Sounds like the ccfl inverter is buggered. Search here Link to comment Share on other sites More sharing options...
carl0s Posted March 7, 2006 Share Posted March 7, 2006 This guy managed to fix his yesterday by replacing a capacitor: Bought some old LCD monitors with non-functioning backlights. In examining the CCFL driver circuit, it appears to be at Texas Instruments TL1451 PWM regulator chip driving essentially a solid state tesla coils for the HV/HF output. Did some checking with my scope and found the 1451 didn't appear to be switching the output transistors, so I replaced it with a new 1451 chip and everything works great. I shut the power off and come back 10 minutes later to button up the case and the lights won't turn on again! To make a long story short, through trial and error, I found that if I touch any lead of the chip for a few seconds with a soldering iron (heat it up) the chip works and back lights come on. If it cools off to room temp, the chip won't work. So now I have two monitors with the original chips and two monitors with new chips that do the same thing. I sat down with one chip and could literally touch a lead for 3 seconds with the soldering iron and get it to function normally, then put a couple drops of liquid freeze on it and the chip would quit. Anybody know why my chips work at say 120F, but not at room temp? Thanks Corey here's a picture: http://www.uk2sucks.net/CCFLdriver.jpg Check or replace C2. All, Thanks for all the posts. As usual, the wealth of information on this forum is stunning. As suggested, I dug deeper into the caps and found some issues. I replaced them as suggested and now have all the inverters operational hot or cold. Thanks again for the input. Corey Link to comment Share on other sites More sharing options...
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