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l755 imag very dim after big stupidity

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    l755 imag very dim after big stupidity

    Well didnt notice battery was still on chassy , and removed the bloody lvds connector , now it turn on , i can see very barely in the deep of the screen the images , but cheked yesterday LCD VCC was 5.8 volts , today i lifted pq20 and pq18 , to test them , and reinserted them and i got now different values.

    page 22 of schematic cheked the LCD switch circuit , cheked that PQ21 i got the 3.3 volts from VPCU on pin 3 . and also got the 3.3 volts on the gates of pq20 and pq19 .

    once i press on , the LVDS_DIGON will send a 3.3 volts signal do the gate of Q21 making the +3vpcu to drop to 0 volts , once that happen i got 13.76 volts on pin 3 of Q20 and PQ 18 i got pin 1 3.3 volts , pin 2 13.7 volts and pin 3 - 3.3 volts .

    so since i dont have here the LCD to test it out . my question is LCD VCC should be 19 volts as usual right ?

    Also noticing that RM1 hall sensor and backlight switch on the same page 22 , i got 3.3 on pin 1 and 2 . with or without machine turned on
    any toughts ?
    thk in advance

    #2
    Re: l755 imag very dim after big stupidity

    post schematic, because i dont have it.

    start from inverter by pinout from image.

    vcc - 19V
    ena - 3.3V
    adj - 0-3.3/3.3 is full light/
    Attached Files
    Last edited by ktmmotocross; 11-06-2014, 08:16 AM.

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      #3
      Re: l755 imag very dim after big stupidity

      ups sorry here it is the schematic
      Attached Files

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        #4
        Re: l755 imag very dim after big stupidity

        pin 22 and 23 of lvds connector i got 19.6 vlts
        pin 20 i got 0 volts with or withuot turning it on ,
        pin 19 i got 3.3 volts.

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          #5
          Re: l755 imag very dim after big stupidity

          Pin 1,2 =3.3v ?

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            #6
            Re: l755 imag very dim after big stupidity

            yes

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              #7
              Re: l755 imag very dim after big stupidity

              well guess that not having pin 20 at least 3.3 than screen will not turn on , only thing is concerning me is lcd vcc beeing 3.3 volts !

              cheked pin 6 of nuvoton and its 0 . will try inject 3 volts on that rail and see what will move forward

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                #8
                Re: l755 imag very dim after big stupidity

                injecting will make the kbc to get a bit warmer, but no changes altough

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                  #9
                  Re: l755 imag very dim after big stupidity

                  check all components on page 22, block LDS

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                    #10
                    Re: l755 imag very dim after big stupidity

                    Sio problems , replaced and all good

                    Comment


                      #11
                      Re: l755 imag very dim after big stupidity

                      Originally posted by highpulse View Post
                      Sio problems , replaced and all good
                      good job and you got lucky my friend made the notebook dead like you
                      Just cook it! It's already broken.

                      Comment


                        #12
                        Re: l755 imag very dim after big stupidity

                        eheheheh , well its a open eye even that we do all this steps tausands of times , somethimes when to much pressure , we allow us to make mistaque but we shouldn't , but well , i simply lost to much time due to a stupidity .. thinking that lcdvcc should be 19 volts .... since beggining not having pin 20 i knew KBC was faulty .. my only problem was pin 1 and 2 of lvds ... and i wasw wrong since the main feedline was at pin 22 and 23 well , it was a good error to remind me few basics steps

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