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    Clevo P375SM-A Motherboard LED Backlight Fuse Location

    Discussion in 'Sager and Clevo' started by MahmoudDewy, Sep 20, 2018.

  1. MahmoudDewy

    MahmoudDewy Gaming Laptops Master Race!

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    Hey lads,

    Long story short, I need to find the LED backlight fuse on my Clevo P375SM-A because I triggered it and need to bridge it or solder a new fuse.

    The schematics show nothing and I was wondering if someone had to play with it before instead of me wasting a lifetime with a Multimeter trying to figure out which fuse that is :D
     
    MahmoudDewy, Sep 20, 2018
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  2. poprostujakub

    poprostujakub Notebook Consultant

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    Emmm... there isn't any fuse in LED circuit.... maybe you just burned boost converter, that produce high voltage for LEDs. Check D19 diode near U41 IC and L24 inductor - if it is short, converter will not start.
     
    poprostujakub, Sep 20, 2018
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  3. MahmoudDewy

    MahmoudDewy Gaming Laptops Master Race!

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    Are you sure? I am getting perfect signal but no backlight, could this diode be the cause?
     
    MahmoudDewy, Sep 20, 2018
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  4. poprostujakub

    poprostujakub Notebook Consultant

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    What signal you mean?
    If you don't have backlight, I suppose, that you don't have KB_LED_PWR voltage, 18,58V.
     
    poprostujakub, Sep 21, 2018
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  5. MahmoudDewy

    MahmoudDewy Gaming Laptops Master Race!

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    That's what I missing yes.
     
    MahmoudDewy, Sep 21, 2018
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  6. Prema

    Prema Your Freedom, Your Choice

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    Check the board for a TSSOP14 chip marked U6A, that's the 74LVC08PW (Quad-2-input-AND-Gate) responsible for switching the backlight on and off.

    Usually hot plugging a display with the system battery still connected on an eDP system blows this chip out...
    Had to learn it the hard way and replace it on a P170HM3 and a P150EM until I had learned my lesson.

    You can either get a new one from digikey, ebay etc... or short the thing if you don't care and want the backlight on for good.

    (Service manual with the chips electrical design is on premamod.team in the maintenance section).
     
    Prema, Sep 21, 2018
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  7. Meaker@Sager

    Meaker@Sager Company Representative

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    That step in service manuals telling you to disconnect the battery ain't kidding ;)
     
    Meaker@Sager, Sep 21, 2018
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  8. MahmoudDewy

    MahmoudDewy Gaming Laptops Master Race!

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    On for good as in when the machine is off the backlight stays on ? :D

    Well the machine was completely dismantled no battery no AC power nothing. I just tried to do the 120Hz upgrade with what seems to be a bad edp cable. The 120Hz had no signal, no backlight ... nothing. So I removed the 120Hz and installed back the 60Hz and got the dreaded no backlight issue.

    Needless to say all the swapping was done with no power from any source. I guess the problem came somehow from the edp cable.
     
    MahmoudDewy, Sep 22, 2018
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  9. Meaker@Sager

    Meaker@Sager Company Representative

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    Static could have the same impact or a bad cable shorting connections.
     
    Meaker@Sager, Sep 22, 2018
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  10. MahmoudDewy

    MahmoudDewy Gaming Laptops Master Race!

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    That's what you get from fishy eBay sellers but alas what is done is done. Finding the chip and soldering it is not a very bad Christmas project though :D
     
    MahmoudDewy, Sep 23, 2018
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  11. Meaker@Sager

    Meaker@Sager Company Representative

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    If you don't mind breaking the soldering iron out there are always fun projects to be had with electronics :D
     
    Meaker@Sager, Sep 23, 2018
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