Blank screen on boot

Gary58

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Jan 31, 2013
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Toshiba Satellite L505D-S5965. Windows "Vista" The back-light is not working. The external monitor works fine and when I "Fn + f5" the on-board screen gives a flash of the screen for a second then quits (goes black). using the flashlight trick shows the screen indicating that the screen is good, I replaced the inverter with a "new" one with no difference. I would assume the cable is good. What's left other than the mother-board or graphic card which is probably not separate or replaceable.
 

wiggbot

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Dec 22, 2012
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By inverter I assume you're referring to the AC adapter.

I had this happen to a laptop of mine in the past. Odds are it is the backlight controller on the laptop. Unless you aren't afraid of taking a good portion of your laptop apart, I'd recommend you get a professional to service it.

Out of curiosity, did you notice the brightness get dimmer or perhaps have a bit of a funny tint of colour before it stopped working?
 

Gary58

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Jan 31, 2013
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Thank you for the quick response. By Inverter I am referring to the "backlight Inverter". I just located after all day searching, a bulb! Lots of folks selling inverters but few with the bulb (the would rather sell the screen)! I am pretty sure it is the bulb since I can view the screen with the flashlight. Can't be the card or I wouldn't see it with the light. If any one else is interested I found the bulb at this link http://www.lcdparts.net . As far as the condition when it stopped, I don't know as this one is a friends machine. I will update in about a week when the new part comes in. ... Gary
 

wiggbot

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Dec 22, 2012
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My apologies. Seems like I misread your first post.

So you replaced the inverter, and yet the backlight still will not come on? Damn...

I had the exact same issue. If I shined a flashlight onto the screen, you can see that the image was there. As mentioned, my issue was resolved by replacing the inverter.

If you're taken it apart that far, I assume you aren't afraid of doing a little bit of troubleshooting. If you've got a multimeter, test to see if the inverter is being powered or not. CAFEFUL NOT TO SHORT CONTACTS! If not, trace back the wire. I'm uncertain where your inverter is located, but mine was under the screen bezel. A possibility could be the wire may be damaged from opening/closing the laptop.

If the inverter is getting power, perhaps the bulb itself is burnt out. A quick google search shows me that there is just one bulb in there.

That's all that springs to mind at the moment. Maybe you've got a BIOS setting for brightness you can change that, but I'm almost certain that this is a hardware issue.
 

Gary58

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Jan 31, 2013
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Yea I'm pretty sure your correct. I have 3 dells completely dismantled on my bench. My cat decided to re-arrange the parts the other day. Now is NOT the time to be afraid! Just "Nuts'n'Bolts" The inverter has power, I was hoping it would be the inverter, so much less spooky!!