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Motherboard LA-9105P, no CPU power, 7 beeps

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    #1

    Motherboard LA-9105P, no CPU power, 7 beeps

    Hi everyone,

    Have LA-9105P motherboard with no power on +VCC_CORE, resistance 4 Ohms.

    Both BIOS firmwares (4MB and 2MB) was re-writed.

    PCH_PWROK are OK 3.3V
    VR_ON OK 3.3V

    After board turn on SLP_S5#, SLP_S4# and SLP_S3# the signal level rises to HIGH and immediatly fall to LOW.

    Cooler keeps running and voltages stay on it's work values.

    Post card connected to 30 and 31 pins of kb9012qf no POST codes.

    CPU PWM controller ISL95833 was replaced without results.

    PCH and CPU are cold. May be someone can help found reason of such behaviour?
    Last edited by Artuha; 03-27-2018, 03:58 AM.
    Tags: None
    #2
    Re: Motherboard LA-9105P, no CPU power, 7 beeps

    1)Switch on your laptop by pressing power on.

    2)Switch it off by pressing power button for long time.

    3)Switch it on again while holding fn key on your lappy.

    Solved .

    Comment

      #3
      Re: Motherboard LA-9105P, no CPU power, 7 beeps

      Check Resistor connected to QZ11. You should get 19v and 12v at the two ends of this resistor. If 12v missing -no vcc

      check PU400 also.

      Comment

        #4
        Re: Motherboard LA-9105P, no CPU power, 7 beeps

        Sorry not 12v but 5v i meant.
        Check QZ1 pin 4-5v present or not

        Comment

          #5
          Re: Motherboard LA-9105P, no CPU power, 7 beeps

          Originally posted by petehall347 View Post
          1)Switch on your laptop by pressing power on.

          2)Switch it off by pressing power button for long time.

          3)Switch it on again while holding fn key on your lappy.

          Solved .
          No. This method do not resolve my issue.

          Comment

            #6
            Re: Motherboard LA-9105P, no CPU power, 7 beeps

            Originally posted by mcplslg123 View Post
            Check Resistor connected to QZ11. You should get 19v and 12v at the two ends of this resistor. If 12v missing -no vcc

            check PU400 also.
            QZ11 have two resistors RZ18 (one side 19.8V other 15.4V) and RZ21 (one side 15.4V and other ground) UZ1 are open and make +1.5V from +1.5VS

            I do not have idea how 5V can be on resistors, but I'm newbie in electronics and may be wrong. See 1.jpg and correct me if I'm wrong.

            About PU400 - on PL400 I have 1.8V - in my opinion PU400 works as expected.

            QZ1 also works Gate 19V source and drain 5V
            Attached Files

            Comment

              #7
              Re: Motherboard LA-9105P, no CPU power, 7 beeps

              I use LA-9104P schematics

              Comment

                #8
                Re: Motherboard LA-9105P, no CPU power, 7 beeps

                Have you checked voltage on isl95833 VDD pin#21 or pr720 both side.

                Comment

                  #9
                  Re: Motherboard LA-9105P, no CPU power, 7 beeps

                  Yes, VDD and VCCP on ISL95833 are 5V

                  Comment

                    #10
                    Re: Motherboard LA-9105P, no CPU power, 7 beeps

                    hi . is your problem solved ? . i have same problem.help me please ?

                    Comment

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