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W520 backlight issue, bad fuse F24

2018-11-06, 22:39 PM


I'm having the same issue I had in 2012 with my W520 laptop. Back then, it was still under warranty so I sent the laptop back for repair. This time I'm trying to fix the issue myself. 

I have no backlight, I can see a faint image at boot but when the graphic card take over the onboard graphics, the screen is all black. I tried to plug it to an external display and there's an image but Windows doesn't detect my main monitor. I thought it may be a driver issue so I tried to update my drivers but with no luck. When I tried to disable the graphic card (thinking it would revert to on board graphics) I lost all display.  Also, the keyboard stopped working at the same time I lost backlight (I had the same issue in 2012, screen backlight and keyboard failed at the same time) 

After dismanteling the laptop and testing fuses, I've found out that the fuse F24 has gone bad. I'd like to replace it and I think it's a 500mA, 32V fuse. I don't know where I can buy one. I saw a bunch on Digi-Key but there are so much to choose from.

I know the part size , current and voltage rating but I don't know what melting I^2t I should go for.

The part on the schematic I found online is FUSE-500MA32V-GP, 


Thanks for your help



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Re: W520 backlight issue, bad fuse F24

2018-11-07, 0:32 AM

The 0.5 amp fuse is the one that controls the LEDs on the LED sub card.  (the status LEDs inside the lid) The backlight is a 2 or 3 amp fuse.  It is usually near the cable location, either on the top or bottom of the board.  I don't remember if it is 2 or 3 amps.  They are made by Littelfuse and you can buy them from Mouser Electronics.  The 0.5 amp fuse often blows at the same time as the backlight fuse.


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