Benq W1070 projector power supply short

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  • tibimakai
    Badcaps Legend
    • Jan 2012
    • 3680
    • USA

    #1

    Benq W1070 projector power supply short

    I have picked up this pj, that was dead, no sign of light.
    It was fully packed with dust and it cooked itself.
    Safety switch wires were backed, that the insulation it was mostly gone and hardened.
    After cleaning and replacing those wires, I have started measuring and I have found an open T6.3A/250V F601 fuse.
    Also I have found Q601 mosfet completely shorted.
    SM is available, at elektrotanya. Power supply is on page #18.
    My question is, if this FET has shorted, what else could be damaged? IC601 may be damaged as well? Rectifier is OK.
    Any help would be appreciated.
  • budm
    Badcaps Legend
    • Feb 2010
    • 40746
    • USA

    #2
    Re: Benq W1070 projector power supply short

    The IC that drives the MOSFET's Gate and the components connected to the Gate may be damaged also, plus if there is Source resistor, it can be blown too.
    Never stop learning
    Basic LCD TV and Monitor troubleshooting guides.
    http://www.badcaps.net/forum/showthr...956#post305956

    Voltage Regulator (LDO) testing:
    http://www.badcaps.net/forum/showthr...999#post300999

    Inverter testing using old CFL:
    http://www.badcaps.net/forum/showthr...er+testing+cfl

    Tear down pictures : Hit the ">" Show Albums and stories" on the left side
    http://s807.photobucket.com/user/budm/library/

    TV Factory reset codes listing:
    http://www.badcaps.net/forum/showthread.php?t=24809

    Comment

    • tibimakai
      Badcaps Legend
      • Jan 2012
      • 3680
      • USA

      #3
      Re: Benq W1070 projector power supply short

      Thanks Bud for your help.
      Pins #10 and #8 are not shorted to ground.
      I have measured the components around the transistor, and nothing seems damaged.

      Comment

      • yokoono
        Badcaps Veteran
        • Apr 2010
        • 481

        #4
        Re: Benq W1070 projector power supply short

        When the mosfet is short, the 310v voltage reaches the integrated controller. That destroys it irremediably. Replace the integrated controller, mosfet, resistors, diodes between the integrated output and the mosfet gate. Check the rectifier bridge.
        Last edited by yokoono; 07-28-2019, 02:23 AM.

        Comment

        • tibimakai
          Badcaps Legend
          • Jan 2012
          • 3680
          • USA

          #5
          Re: Benq W1070 projector power supply short

          I tried replacing only the Mosfet, (to me it seemed like nothing else was bad) the IC was three weeks away anyway.
          It worked. Now I need to clean it, it is worse than a neglected desktop pc.
          Thanks guys, for helping.

          Comment

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