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Compal IFL90 turns on, but screen and vga port is dead

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    Compal IFL90 turns on, but screen and vga port is dead

    I accidentally plugged the connector from "Camera Conn" JP3 header on page 42 into "Inverter Conn" JP37 header on page 18. When I turn on my laptop, the fan spins up, the front panel lights turn on, but my laptop does not boot. I probably fried the KB925QF on page 34, correct? Is the KB925QF a chip that the laptop manufacturer custom programs? There are some KB925QF chips on Ebay. Could I have damaged other other components (resistors, diode, inductors, caps) on page 18?
    Last edited by SMDFlea; 08-15-2020, 04:27 AM. Reason: removed dead link

    #2
    Re: KB925QF replacment

    Do you get backlights on the screen to see anything on the screen?
    What does it do if the camera not connected to JP3?
    If you look at the power pins and the GND pins are setup for the JP3 header and the JP37 header, I would think the camera circuit may be damaged, and switched MOSFET for +INV POWER may be damaged.
    The inverter is probably OK and not damaged when plugged into wrong connector JP3 but the power +5V line on pin 1 of the JP3 may have been grounded out.
    You need to check the power pins of both headers. Things get damaged when power and GND pins are connected wrong to the loads.
    Last edited by budm; 08-15-2016, 09:39 PM.
    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


      #3
      Re: KB925QF replacment

      Originally posted by budm View Post
      Do you get backlights on the screen to see anything on the screen?
      What does it do if the camera not connected to JP3?
      If you look at the power pins and the GND pins are setup for the JP3 header and the JP37 header, I would think the camera circuit may be damaged, and switched MOSFET for +INV POWER may be damaged.
      The inverter is probably OK and not damaged when plugged into wrong connector JP3 but the power +5V line on pin 1 of the JP3 may have been grounded out.
      You need to check the power pins of both headers. Things get damaged when power and GND pins are connected wrong to the loads.

      The screen is completely black. I shined a bright light on the screen, and I did not see an faint image. The problem in the original post still occurs, if the camera is not connected to JP3.

      Comment


        #4
        Re: KB925QF replacment

        I connected an external monitor to the laptop's VGA port and nothing appeared on the external monitor's display.

        Comment


          #5
          Re: KB925QF replacment

          JP37

          Power is on:
          19.38v Pin6
          19.38v Pin7

          Power is off:
          Continuity check
          overload Pin 3
          1417 Pin 4
          overload Pin 5
          overload Pin 6
          overload Pin 7
          0 Pin 1
          0 Pin2
          Attached Files

          Comment


            #6
            Re: KB925QF replacment

            Here is another manual.

            I measured the voltage of each pin:

            Inv_pwm 0.13v
            DispOff# 2.62v
            Dac_brig 0.11v
            Inv_pwr 19.38v
            Attached Files
            Last edited by 49studebaker; 08-14-2020, 11:29 PM.

            Comment


              #7
              Re: Compal IFL90 KB925QF replacment

              Pin 1 on JP14(EC Debug Port) has 3.3v

              Comment

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