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    #1

    Dell 3542 powers on then off or goes to sleep

    Dell inspiron 3542 -13269 1-with discrete graphics card on, i7 processor.
    Do not have many tools. Multimeter.
    And i am beginner at this.

    So,
    I am using bare motherboard, (without RAM, HDD, etc).
    Power given from power adapter 19V output DC working ok.

    I measured voltages on big coils (both ends) before i push the power button and after.
    And also resistances of coils to ground.


    ----------------Before:--------------------- after-------------resistance to gnd
    PL4902---0.00V 0.00V--------1.35V 1.25V --------0.4 kohm
    PL4502---3.10V 3.10V--------3.40V 2.10V --------2.4 kohm
    PL4501---5.10V 5.10V--------5.20V 5.10V --------18 kohm
    PL8201---0.00V 0.00V--------0.90V 0.74V --------17 ohm
    PL8202---0.00V 0.00V--------0.90V 0.74V --------17 ohm
    PL4801---0.00V 0.00V--------1.04V 0.76V --------160 ohm
    PL4701---0.00V 0.00V--------1.74V 0.34V --------100 ohm
    PL4401---2.60V 2.60V--------2.70V 2.70V --------15 Mohm

    Now i am going to slowly dive into the schematic power sequence....
    Any hints? Ideas?
    Last edited by RememberTheViolin; 01-10-2021, 10:13 AM.
    Tags: None
    #2
    Re: Dell 3542 powers on then off or goes to sleep

    I follow the steps of power sequence diagram that i found in the forum (page 97).

    I took measurements
    A. first with voltage on without pressing power button
    B. second after pressing powerbutton


    step(-4)
    NPCE285 pin 33 A=3.2V B=3.2V
    NPCE285 pin 19 A=3.2V B=3.2V
    NPCE285 pin 115 A=3.2V B=3.2V (3D3V_AUX_KBC)

    step(-1)
    NPCE285 pin 15 A=3.1V B=3.1V (RSM RST #_KBC)

    step(2)
    NPCE285 pin 117 A=3.1V B=0V AND THEN AGAIN 3.1V (PM_PWRBTN#)

    step(3a)
    1D35V_S3 (R3706) A=0.0V B=1.35V

    step(4b)
    PU4901 pin 20 A=0.0V B=3.3V PGOOD
    pin 13 A=0.0V B=1.25V SW
    pin 16 A=0.0V B=3.4V S5
    pin 17 A=0.0V B=5.1V S3

    step(6)
    NPCE285 pin 100 A=0.0V B=3.1V (PCH_PWROK)

    step(10)
    NPCE285 pin 64 A=0.0V B=3.3V (SLP_S3#)

    step(12)
    NPCE285 pin 7 A=0.0V B=3.4V (PLT_RST)


    PU4601
    step(9) pin 2 A=0.0V B=3.2V (PGOOD)
    step(7) pin 1 A=0.0V B=1.0V (VR_ON)
    pin 12 A=0.0V B=5.0V (VCC)
    pin 18 A=0.0V B=1.03V (SDA)
    step(11) Pin 16 A=0.0V B=4.3V (LGATE)

    step(8)
    at PL4701 1.74 VCC_CORE

    step (-7) ok
    step (-6) ok
    step (-5) ok
    step (-4) ok
    step (-3) ok
    step (-2) ok

    Any suggestions?
    Last edited by RememberTheViolin; 01-11-2021, 07:44 AM.

    Comment

      #3
      Re: Dell 3542 powers on then off or goes to sleep

      ok. now sth happened.
      voltage on PL4501=0V, and 0 ohm to gnd.
      on PU4503 pin 7=0v (pgood), pin18=0v, pin2=0v.
      so 5V ...off...

      Comment

        #4
        Re: Dell 3542 powers on then off or goes to sleep

        Originally posted by RememberTheViolin View Post
        ok. now sth happened.
        voltage on PL4501=0V, and 0 ohm to gnd.
        on PU4503 pin 7=0v (pgood), pin18=0v, pin2=0v.
        so 5V ...off...
        So overall you’re are trying to tell MB power & shut down immediately ? are the heatsink fan RAM ddr 3L connected ?

        step(-1)
        NPCE285 pin 15 A=3.1V B=3.1V (RSM RST #_KBC)
        this voltage must go to 0V & come back to +3V
        Last edited by Techtiger; 01-13-2021, 04:03 AM.

        Comment

          #5
          Re: Dell 3542 powers on then off or goes to sleep

          Hi,

          What i mean with PL4501=oV is that this chip PU4503 is no longer working, it does not give me the 5V output anymore. I am wondering if it died. I have the measurements for all its pins (voltage and resistance to gnd) and investigating (attached below).

          Heatsink fan is connected. 2 days ago (before PU4503 stopped working) after powerbutton was pressed, heatsink fan started and then stopped after 3 seconds. But i was able to do voltage measurements on other chip controllers (PU4901, PU4601,PU8201) which shows that it did not shutdown maybe went to sleep or standby?

          Now not even the fan starts at all.

          RAM (working RAM) is not installed.
          Attached Files
          Last edited by RememberTheViolin; 01-13-2021, 06:20 AM.

          Comment

            #6
            Re: Dell 3542 powers on then off or goes to sleep

            Does it out put 3D3V_PWR ? Check PU4501/2 for any short and PU4501 pin 5678 gets 19V ?
            Test PC4518 PT4501 for any short
            Last edited by Techtiger; 01-13-2021, 09:24 AM.

            Comment

              #7
              Re: Dell 3542 powers on then off or goes to sleep

              In the first measurement you had received 2,10v in the PU4502, there may be a short circuit in the 3.3v circuit after start, good work.
              I'm not happy to be so strong. because it's not humanly

              Comment

                #8
                Re: Dell 3542 powers on then off or goes to sleep

                Hi techtiger,
                yes PU4503 outputs 3.3v at pin8 confirmed.
                PU4501 pins, 5,6,7,8 get 19V.
                PC4518 is not installed from factory, empty pads. haha

                No soldering iron (for the moment)
                so, big capacitor PT4501 is not getting hot compared to PT4502
                but PU4503 is getting instantly hot (instantly dries out from alcohol while
                all other mosfets PU4501,PU4502,PU4504,PU4505 stay wet).
                PU4503 probably dead....

                So, quick pause for me to get a soldering iron.

                Hi Sametbey.
                Thanks. I will check it out.
                Last edited by RememberTheViolin; 01-13-2021, 10:59 AM.

                Comment

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