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HP ProBook 450 G2 some strange charger voltages

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    HP ProBook 450 G2 some strange charger voltages

    Hi, I have HP 450 G2 with i5 and ATI graphics and broken DC jack. Battery is dead so I connected lab psu on motherboard and find that 3V3 and 5V are present. Also, 3V3 are present on KBC and many "enable" signals are ok. There is no reaction on power button but KBC are reacting. power button lit all time. Since DC jack is broken, I can't see signals from dual-color LED. Furthermore, I measured some strange readings, visible on picture. Charger chip produces 24 volts and sends to one mosfet. Everything is stone cold, virtually no power drained from psu. Other problem is how to make motherboard to recognize smart pin connector?
    Attached Files

    #2
    Re: HP ProBook 450 G2 some strange charger voltages

    24V on the gate is normal. PQ102 is a N-Channel MOSFET so it needs a voltage on the gate higher than the source (which is 19V — AC adapter voltage). Charger IC boosts the AC adapter voltage to 24V when everything in charging circuit works to turn on the MOSFET.

    On HP the motherboard usually won't boot if AC adapter is not recognized properly.

    I don't remember the values but you can put a resistor between the positive side of the DC in connector and the ADP_SIGNAL pin (or whatever it is called). On the motherboard there is another resistor network that acts as a voltage divider to get a voltage depending on the AC adapter power rating going into the EC.
    OpenBoardView — https://github.com/OpenBoardView/OpenBoardView

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      #3
      Re: HP ProBook 450 G2 some strange charger voltages

      Thanks! It seems that datasheet for bq24736 is not easy to find and similar ones are all different on several parameters.

      Comment


        #4
        Re: HP ProBook 450 G2 some strange charger voltages

        As before, I've worked on HP boards before now that were totally dead when a non-genuine AC adapter was used, but fine with a genuine adapter. I would be tempted to repair the DC jack and try a genuine adapter personally, if you have the means to do so.
        Dell E7450 | i5-5300U | 16GB DDR3 | 256GB SSD

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          #5
          Re: HP ProBook 450 G2 some strange charger voltages

          PU102 (and the whole charging circuit) is working fine, don't touch it.
          OpenBoardView — https://github.com/OpenBoardView/OpenBoardView

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            #6
            Re: HP ProBook 450 G2 some strange charger voltages

            Thanks for fast replies! Power jack is totaly destroyed so I'll buy used one and than start from beggining in a few days.

            Comment


              #7
              Re: HP ProBook 450 G2 some strange charger voltages

              I bought another laptop with good battery and power adapter just for DC-jack. Price was almost 3x higher but it's great deal regardless it's faulty, as described in this thread:
              https://www.badcaps.net/forum/showth...947#post846947

              Now I was able to connect dc-jack with power adapter and things are same when lab psu was connected. Only difference was that now I have light signals. Nothing changed when I plug in fully charged battery (charged on that other laptop). Only signal I get is constantly blinking white light on dc-jack. So, I suspect that power adapter have not enough power because it's 45W. Than I attached original, charged battery and get same singaling. White LED blinks unstoppable. All ALW voltages are present regardless of power source but nothing else.
              If needed, I can upload schematics.

              Any ideas, regarding both casses?
              Thanks in advance!

              Comment


                #8
                Re: HP ProBook 450 G2 some strange charger voltages

                Schematic...
                Attached Files

                Comment


                  #9
                  Re: HP ProBook 450 G2 some strange charger voltages

                  Try flashing BIOS.
                  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


                    #10
                    Re: HP ProBook 450 G2 some strange charger voltages

                    It is on the list! Just couple other things to check...
                    TY

                    Comment


                      #11
                      Re: HP ProBook 450 G2 some strange charger voltages

                      I found missing rails +5VS and +3VS. They are sucessors from +5VDS and +3VDS which are present untill Q21 cuts them off, I think because of missing SLP_S3#. Also, SLP_S4 and SLP_S5 are missing, too. Present voltages are 3V_PCH (3.4V), SYS_RESET# (3.4V) and ON/OFFBTN# (3.0V). All missing SLP points have resistance to ground about 500 ohms.
                      Also present are:
                      3VDS=3.4V; 3VLP=3.3V, DPWROK=3.4V, +3VPCH=3.4V, BATLOW=3.4V, RTCVCC=3V, RTCBATTR=3V
                      On EC measured:
                      pin 75 SLP_SUS=1.98V, pin 122 KBRST=0.2V, pin 99 AC_PRES_OUT=3.4V (not reacting on power button), pin 4 ON/OFFBTN#=3.4V (not reacting on power button), pin 73 ON/OFF_KBC#=3.4V (shorting from 3.4 to 0V on power button).
                      Last edited by kronikus; 08-28-2018, 10:19 AM.

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                        #12
                        Re: HP ProBook 450 G2 some strange charger voltages

                        Readings from lab power on those rails separated on jumpers from ALW lines.
                        +5VS drawing 30mA
                        +5VL drawing 90mA
                        +3VDS 30mA
                        +3VLP 50mA
                        +3VL 0mA

                        EC pin:
                        77 VCC_PWRGD 3.4V
                        99 AC_PRES_OUT 3.4V
                        100 KBC_PWR_ON=3.4V
                        124 BATLOW=3.4V
                        73 ON/OFFBTN=reacting on button
                        69 KBC_XTAL SUSCLK_KBC=0V
                        75 SLP_SUS=1.98V
                        93 SIO_SLP_A#=0V
                        98 SUS_PWR_ACK=0.1V
                        122 KBRST=0.2-0.4V
                        85 RSMRST=0V
                        72 PWRGD=0V

                        BIOS:
                        All pins are 3.4V except
                        pin 2=0.2V and
                        pin 4 on ground.

                        Comment


                          #13
                          Re: HP ProBook 450 G2 some strange charger voltages

                          Since BIOS programmer will not arrive any time soon, does anyone have any other idea regarding missing SLP-S3? I can't clarify enough power sequence from that lo-res picture. Maybe I missing some obvious error?

                          Comment


                            #14
                            Re: HP ProBook 450 G2 some strange charger voltages

                            Also, if charging circuit are working fine as piernow wrote - why laptop donesn't charge batery?

                            Comment


                              #15
                              Re: HP ProBook 450 G2 some strange charger voltages

                              Charging battery is also controlled by BIOS.
                              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

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