Acer V17 Nitro Black Edition (VN7-791) Keyboard backlight Not working

Member Posts: 5 New User
Hi, 
In my old laptop after replacing CPU fan keyboard backlight not working :anguished:.
I checked(few times) connector on motherboard, and looks like connected correctly.

Before fan replacing everything was ok.

Anyone can help me? 

Answers

  • JackE
    JackE ACE Posts: 44,462 Trailblazer
    There are two KB connectors. The small connector is for the backlight usually with a black(-) and red(+) wire. It is either not connected, not fully seated or connected backward.  Jack E/NJ


    Jack E/NJ

  • Easwar
    Easwar Member Posts: 6,727 Guru
    Hi,

    The only backlight option I know is turning the backlight on and off, which is Fn + F9. Did you try this ?
  • Member Posts: 5 New User
    Easwar said:
    Hi,

    The only backlight option I know is turning the backlight on and off, which is Fn + F9. Did you try this ?
    Yes, Fn + F9 not working.
  • Member Posts: 5 New User
    JackE said:
    There are two KB connectors. The small connector is for the backlight usually with a black(-) and red(+) wire. It is either not connected, not fully seated or connected backward.  Jack E/NJ


    I tried few times to connect this and this looks like connected correctly. (this is not my first time when i dissasembly this laptop)
  • JackE
    JackE ACE Posts: 44,462 Trailblazer
    Try F9 just in case the function key behavior somehow got messed up in the BIOS. If that doesn't work, my best guess is that one or both of the wires in the KB female might've pulled out a bit and not making good contact with the mainboard connectior pins. Or maybe a pin got bent to the side. Did you pull on the wires or the connector itself with tweezers to disconnect? If necessary, you could independently check the KB backlight itself by sticking pins in the KB connector and then impressing 3 volts DC (2 alkalines in series). Jack E/NJ

    Jack E/NJ

  • Easwar
    Easwar Member Posts: 6,727 Guru
    Hi,

    # Try to update the keyboard driver
    1. Hold windows key and hit letter X.
    2. Choose the device manager option.
    3. Go with the option keyboard.
    4. Under the title standard keyboard.
    5. Right click on that option ----> Update driver.
    6. Choose "search automatically". 

    Laptop keyboard not working on Windows 10

    Check this T/S and post the result. 

  • Member Posts: 5 New User
     said:
    JackE said:
    There are two KB connectors. The small connector is for the backlight usually with a black(-) and red(+) wire. It is either not connected, not fully seated or connected backward.  Jack E/NJ


    I tried few times to connect this and this looks like connected correctly. (this is not my first time when i dissasembly this laptop)

    Easwar said:
    Hi,

    The only backlight option I know is turning the backlight on and off, which is Fn + F9. Did you try this ?
    Hi, I made few photo of connector and connectot tape:

    https://ibb.co/kKFY2md
    https://ibb.co/pnDhRdc
    https://ibb.co/Kr4CqYY
    https://ibb.co/HdZxJg9

    In my opinion everything looks fine.
  • JackE
    JackE ACE Posts: 44,462 Trailblazer
    Possibly one or both wires feeding the backlight connector pulled away from the connector's female terminal inside. Also, if they're solid vs stranded wires, there may a break inside the insulation somewhere between the KB and the connector. Another more serious possibility is ESD when replacing the fan. Did you wear a grounded wrist strap?   Jack E/NJ 

    Jack E/NJ

  • Member Posts: 5 New User
    JackE said:
    Possibly one or both wires feeding the backlight connector pulled away from the connector's female terminal inside. Also, if they're solid vs stranded wires, there may a break inside the insulation somewhere between the KB and the connector. Another more serious possibility is ESD when replacing the fan. Did you wear a grounded wrist strap?   Jack E/NJ 
    I don't have any grounded wrist strap? Exist any way to test this, i want check only keyboard backlight?(maybe connect this to external energy source, exist any tester to check this?), then I will know if it has damaged is keyboard leds or connector on motherboard
  • JackE
    JackE ACE Posts: 44,462 Trailblazer
    The mainboard output pins should be about 5 volts DC. You should start to see keyboard backlight by applying at least 3 volts dc. You can make your own ESD wrist strap from a wristwatch when working around mainboards and sensitive integrated circuits. Jack E/NJ





     

    Jack E/NJ