Announcement

Collapse
No announcement yet.

Acer 7736z no power on, can't figure it out

Collapse
X
Collapse
 
  • Page of 1
  • Filter
  • Time
  • Show
Clear All
new posts
Previous template Next
    #1

    Acer 7736z no power on, can't figure it out

    Schematic here.

    I have this laptop which does not power on, nothing happens when i press the power button I have 3.3v and 5v standby, i am getting power to the KBC and BIOS, and the power button has 3.3v also. The button is good. I have not found any shorted parts, have checked all main rails.

    What i have noticed is that 3.3v and 5v main do not come up. S5_ENABLE going from KBC to U62 ISL62392 is at 0.39v and goes to 0v when the power button is pressed. I think it should be the other way round and it should go to 3.3v but it does not.

    Things i have tried: Flashing BIOS. Same behavior.
    Forcing enable to 3.3v standby. 3.3v standby drops to 2.2v or something, although i do not have high current (it's under 1mA) and the main power supply still does not power on.
    Replaced U62 with a new one. Same thing.
    Replaced KBC. Still the same.

    Measuring without power, S5_enable is not shorted so i do not understand why it does not go to 3.3v. I've run out of ideas on this one. Any help is welcome.
    Originally posted by PeteS in CA
    Remember that by the time consequences of a short-sighted decision are experienced, the idiot who made the bad decision may have already been promoted or moved on to a better job at another company.
    A working TV? How boring!
    Tags: None
    #2
    Re: Acer 7736z no power on, can't figure it out

    resistors around s5_enable/p.42/ signal have right resistance? diode D13 is ok?

    Comment

      #3
      Re: Acer 7736z no power on, can't figure it out

      The word out there is that U58 gets shorted...

      Comment

        #4
        Re: Acer 7736z no power on, can't figure it out

        All mosfets have been tested ok, no shorts. I'll try checking the resistors and diode D13 although i doubt i will find anything interesting.
        Originally posted by PeteS in CA
        Remember that by the time consequences of a short-sighted decision are experienced, the idiot who made the bad decision may have already been promoted or moved on to a better job at another company.
        A working TV? How boring!

        Comment

          #5
          Re: Acer 7736z no power on, can't figure it out

          Remove L27 and L28, supply current and check if anything draws current and what is getting hot. Main suspect is shorted vga.

          Comment

            #6
            Re: Acer 7736z no power on, can't figure it out

            This has onboard video. But i will try that before i put the thing back together and send it back.

            This is from work (i made the mistake of going back to work) and my boss said the guy who brought it in keeps calling twice every day and he's already pissed off about that, so he'd rather have us give it back still broken, than being bothered continuously by phonecalls. I can understand that. It's happened before at the shop and it's annoying indeed. However, it's funny how this never happened with any of *my* customers.
            Originally posted by PeteS in CA
            Remember that by the time consequences of a short-sighted decision are experienced, the idiot who made the bad decision may have already been promoted or moved on to a better job at another company.
            A working TV? How boring!

            Comment

              #7
              Re: Acer 7736z no power on, can't figure it out

              Removed coils and applied 3.3 and 5v from PC PSU, nothing getting hot and current consumption is low. I'm not bothering with this one anymore.
              Originally posted by PeteS in CA
              Remember that by the time consequences of a short-sighted decision are experienced, the idiot who made the bad decision may have already been promoted or moved on to a better job at another company.
              A working TV? How boring!

              Comment

                #8
                Re: Acer 7736z no power on, can't figure it out

                How about checking if ECRST# is 3.3v?

                Comment

                  #9
                  Re: Acer 7736z no power on, can't figure it out

                  thank you . it was it (U58)

                  Comment

                  Previous template Next
                  Working...
                  X