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Acer Aspire 5 A515-51 power on but black screen

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    Acer Aspire 5 A515-51 power on but black screen

    Hi,

    I have an acer aspire 5 a515-51 that turns on but has a black screen.

    This laptop has the same symptoms as https://www.badcaps.net/forum/showth...er+aspire+a515, however mine is a different model Acer Aspire A515-51 (without the 'G'). There is no onboard ram on this laptop.

    Description of the problem is the same: I press the power button, the fan spins for a few seconds and then stops, the computer stays on all the time (led blue), the cpu and gpu are lukewarm. If I leave the pc on for a few minutes the fan starts spinning a bit and then shuts down again and the pc stays on all the time.

    motherboard: LA-E891P
    C5V01 REV 1A

    I have tried an external keyboard and although all of the lights on the keyboard flash once when I press the laptop power button, there is no response from the keyboard once the laptop is on. So I can't make the caps lock key illuminate and ctrl-alt-del does nothing.

    Some history: bought faulty with intention to fix but laptop was originally booting into Windows. However, there was always an underlying problem as the laptop would often blue screen as soon as Windows started. Sometimes the laptop would stay on longer but would become unresponsive on a black screen.

    I did a memtest on the ram stick that was inside the laptop and it failed with many errors. I did try cleaning the ram contacts wih alcohol and then it no longer showed any errors in memtest.

    On the last time the laptop booted it blue screened giving the "Irql_not_less_or_equal" message. Upon restarting the laptop it was stuck power cycling. Once I changed the ram the laptop no longer power cycled but would no longer post either.

    Note: I had also seen the "Paged_fault_in_non_paged_area" message in previous blue screen crashes.

    I would like to be able to locate the fault but I am new to board repair so might need things explaining.

    Many thanks in advance

    #2
    Re: Acer Aspire 5 A515-51 power on but black screen

    CapsLock test is inconclusive on some devices, some Acer models apply to this behaviour. Try CTRL+ALT+DEL instead and observe the reaction. Also you might get picture from external display. Try and report.
    FairRepair on YouTube

    Comment


      #3
      Re: Acer Aspire 5 A515-51 power on but black screen

      Originally posted by Sephir0th View Post
      CapsLock test is inconclusive on some devices, some Acer models apply to this behaviour. Try CTRL+ALT+DEL instead and observe the reaction. Also you might get picture from external display. Try and report.
      Thanks,

      I also tried the CTRL+ALT+DEL on an external USB keyboard and there was no result.

      Plugging into an external display over HDMI also didn't yield any results unfortunately.

      Comment


        #4
        Re: Acer Aspire 5 A515-51 power on but black screen

        If you have access to dc supply,give us consumption on dc supply
        01.When off
        02.When powered on

        Measure voltage on all coils after powering on.

        Have you tried known good clean me bios.

        Comment


          #5
          Re: Acer Aspire 5 A515-51 power on but black screen

          Originally posted by mcplslg123 View Post
          If you have access to dc supply,give us consumption on dc supply
          01.When off
          02.When powered on

          Measure voltage on all coils after powering on.

          Have you tried known good clean me bios.
          Thanks for the help.

          Sorry for the delay, I was learning about schematics, boardview and what a coil is.

          I have found a schematic for the LA-E891P-R1A board but I couldn't find a boardview file. Instead I have been using the LA-E892P-R1A boardview which is a very close match.

          Voltage when off = 19.48V
          Voltage when on = 19.39V

          I measured the voltage at pins 1 and 2 of the header on the main board (PJP101).

          For the coils when on:
          PL906
          pin 1 0.0V
          pin 4 0.0V

          PL904
          pin 1 7.8V
          pin 4 0.99V

          PL907
          pin 1 0.57V
          pin 4 1.0V

          PL602 (Not sure of the pin orientation for this coil is it is slighlty different in the boardview file)
          pin 1 7.15V
          pin 2 11.0V

          PL402
          pin 1 3.1V
          pin 2 3.3V

          PL502
          pin 1 1.2V
          pin 2 12.6V

          PL401
          pin 1 5.2V
          pin 2 5.1V

          PL302
          pin 1 2.84V
          pin 2 2.84V

          From probing the board I have found what I believe are some shorts to ground and they are very close to the PL906, PL904 & PL907 coils.

          The components that I believe are shorted (beeping in continuity mode and measure a resistance of around 6ohms) are:
          PC9095
          PC9069
          PC9070
          PC9033
          PC9032
          PC9034
          PC9031
          PC9035
          PC9049
          PC9050

          "Have you tried known good clean me bios." - I don't know what this means, if it involves removing the bios chip and reprogramming it then I won't be able to as I don't have those tools.

          Comment

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