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Old 09-14-2013, 12:02 PM   #1
Rolin
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Default Asus U57A Backlight Fuse on Motherboard

I have an Asus U57A laptop that would not turn on - completely dead. I troubleshot and found the LCD cable was causing the problem (pretty unusual) - it appeared the cable was kinked and most likely shorting out the motherboard. I ordered another cable and the laptop now turns on, but no display - OK on external monitor though - so now I suspect the backlight is out, and I'm suspecting the shorted cable blew the backlight fuse on the motherboard.

But I don't see any fuses around the LCD connector. Here's a pic of the area, can anyone help me find the fuse?

BTW: The motherboard is printed with K55VD part number.
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Old 09-14-2013, 01:12 PM   #2
jetadm123
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Default Re: Asus U57A Backlight Fuse on Motherboard

The fuse might be on the circuit board mounted inside the LCD panel.
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Old 09-14-2013, 03:42 PM   #3
Rolin
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Default Re: Asus U57A Backlight Fuse on Motherboard

Thanks for the reply. I know about the fuse on the back of the panel and I should probably check it, but I swapped another screen I have (cracked, but backlight works) and it still fails. The fact that the entire motherboard/laptop was dead when the original faulty LCD cable was connected (even when I disconnected it from the screen!) concerns me that some damage to the motherboard occured. Again, after replacing the cable the computer fires up properly on an external monitor. It is possible the new LCD cable is faulty, but I would like to check any obvious things (like fuses) before I consider ordering another cable. Can you see any fuses on the picture I uploaded??
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Old 09-14-2013, 06:08 PM   #4
trebo
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Default Re: Asus U57A Backlight Fuse on Motherboard

no fuses in photo
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Old 09-15-2013, 10:47 AM   #5
Rolin
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Default Re: Asus U57A Backlight Fuse on Motherboard

I guess that's why I didn't see any fuses either...

I just uploaded a picture of the complete front and back of board. Maybe that will help.

I thought there was always a fuse on the motherboard for the newer LED backlight screens. I've had to replace a couple in the past on other boards, but this one I just cannot find. If it's not a fuse, then I guess it must be another component that blew with the shorted LCD cable. But an easy fuse is always preferred!

Let me know if you need a zoomed in shot of a particular area.
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File Type: jpg photo.jpg (942.8 KB, 12 views)

Last edited by Rolin; 09-15-2013 at 10:51 AM..
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Old 09-15-2013, 01:16 PM   #6
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Default Re: Asus U57A Backlight Fuse on Motherboard

i think you will have to give a ultimatum in this case.
1.your board and you need to make it for yourself then you will take all the components near the connector and try to go backwards to find the problem and the purpose of each component.
2.others board you need to tell him that its time wasting and you will not make any progress very fast identifying each comp. fast; needs a new board.
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Old 09-15-2013, 09:16 PM   #7
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Default Re: Asus U57A Backlight Fuse on Motherboard

can u see the picture on the lcd
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Old 09-15-2013, 10:01 PM   #8
Rolin
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Default Re: Asus U57A Backlight Fuse on Motherboard

Not really, it's too dark. I suppose the shorted LCD cable could have blown something other than a fuse. Again, works great on external monitor. Since I don't see any fuse related to the backlight on the motherboard - I guess it's time to look for something else.

Does anyone know if there's a schematic available for this board? I'm lousy at component level troubleshooting, but I'd be up for it if someone wants to help a bit. With the help of some of the members in the past, I've been able to repair a few monitors and a couple of motherboards - I learned a lot and really enjoyed the challenge. How complicated is the motherboard backlight circuit on this board?
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