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  1. #1
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    Dell Alienware 15 R2 power supply shorts LA-C91

    Got this Alienware that wouldn't power up, but now shorts the power supply and the blue light on the charger goes off with a crack noise.
    Obviously a short somewhere, it's not the internal charger port to motherboard lead as this tests OK by itself.
    Any ideas where to start?
    Struggling getting a schematic for this one, but making some sense with the LA-9331P schematic.

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    Re: Dell Alienware 15 R2 power supply shorts LA-C91

    Hi Friend.

    Based in my experience and adding you dont have any schematic of this board you could use an esr meter (i have atlas esr70) to check any mlcc shorted or connect the motherboard to a bench power supply and search for an anormal temp in the components.

    Many of my repairs in dell shorted motherboards were caused for shorted mlcc placed on cpu/ram voltage rails or in the +19v rail.

    Hope this helps.
    Let me know.

  3. #3
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    Re: Dell Alienware 15 R2 power supply shorts LA-C91

    I've got the schematics which helps a lot. Shame I don't have the board view, but most of the components are marked.
    I've injected a voltage onto the 19v rail, but its a dead short so I get a low voltage, albeit at a couple of amps.
    I went round with my digital laser temperature probe but couldn't find any obvious culprits.
    I've also isolated the 5v and 3.3v circuits by removing the bridges, but this didn't remove the short.
    I'm thinking I've got a shorted FET, but need to work out which one it could be.

 

 

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