HP 14, LA-A994P, charging light, power led on for 1 second when power button pressed

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  • ktmmotocross
    Boardkiller
    • Feb 2014
    • 3553
    • slovakia

    #21
    Re: HP 14, LA-A994P, charging light, power led on for 1 second when power button pres

    now i see schematic. yes, but still "measure short to ground and voltage when it is starting on all big grey coils and capacitors"

    Comment

    • iplaypty
      Member
      • Aug 2017
      • 47
      • FLORIDA

      #22
      Re: HP 14, LA-A994P, charging light, power led on for 1 second when power button pres

      Originally posted by ktmmotocross
      If it is starting, u have 3.3 ALW so u must have EC_ON

      measure short to ground and voltage when it is starting on all big grey coils and capacitors

      find short to ground, low voltage /overload/, no voltage /not work/ or bigger voltage /burn/


      @ in schematic means that is not used
      Thank you!

      I did test on continuity mode to those caps (attached photos), they beep on both sides.
      Attached Files

      Comment

      • ktmmotocross
        Boardkiller
        • Feb 2014
        • 3553
        • slovakia

        #23
        Re: HP 14, LA-A994P, charging light, power led on for 1 second when power button pres

        Originally posted by iplaypty
        Thank you!

        I did test on continuity mode to those caps (attached photos), they beep on both sides.
        beep is not short. short is under 4ohm. processor and gpu have low ohms so they beep
        how many ohms do u have?

        chceck for voltage on all big coils when starting

        u have SoC platform, so if something goes wrong, bad is mostly SoC IC
        Last edited by ktmmotocross; 11-29-2017, 08:46 AM.

        Comment

        • iplaypty
          Member
          • Aug 2017
          • 47
          • FLORIDA

          #24
          Re: HP 14, LA-A994P, charging light, power led on for 1 second when power button pres

          Originally posted by ktmmotocross
          beep is not short. short is under 4ohm.
          how many ohms do u have?


          So even if it beeps on both sides, both sides have to be less than 4 ohms?

          Comment

          • iplaypty
            Member
            • Aug 2017
            • 47
            • FLORIDA

            #25
            Re: HP 14, LA-A994P, charging light, power led on for 1 second when power button pres

            Originally posted by ktmmotocross
            beep is not short. short is under 4ohm. processor and gpu have low ohms so they beep
            how many ohms do u have?

            chceck for voltage on all big coils when starting

            u have SoC platform, so if something goes wrong, bad is mostly SoC IC
            Sorry, I am learning a lot from you guys. Thank you!

            The ones close to the screen connector are less than 1 ohm on continuity mode, both sides.
            Attached Files

            Comment

            • ktmmotocross
              Boardkiller
              • Feb 2014
              • 3553
              • slovakia

              #26
              Re: HP 14, LA-A994P, charging light, power led on for 1 second when power button pres

              big coils i mean the big grey cubes.

              check voltages on they when u press power button. it must climbing. when not check for short
              Last edited by ktmmotocross; 11-29-2017, 10:47 AM.

              Comment

              • iplaypty
                Member
                • Aug 2017
                • 47
                • FLORIDA

                #27
                Re: HP 14, LA-A994P, charging light, power led on for 1 second when power button pres

                Originally posted by ktmmotocross
                big coils i mean the big grey cubes.

                check voltages on they when u press power button. it must climbing. when not check for short
                how?

                black lead on ground, red lead on coil +?

                Comment

                • ktmmotocross
                  Boardkiller
                  • Feb 2014
                  • 3553
                  • slovakia

                  #28
                  Re: HP 14, LA-A994P, charging light, power led on for 1 second when power button pres

                  yes and same for short check

                  Comment

                  • iplaypty
                    Member
                    • Aug 2017
                    • 47
                    • FLORIDA

                    #29
                    Re: HP 14, LA-A994P, charging light, power led on for 1 second when power button pres

                    Originally posted by ktmmotocross
                    yes and same for short check
                    PLG1: 10 ohms both sides
                    PLZ2: 8.7 ohms both sides
                    PL1002 165 ohms both sides

                    the rest of the coils are 0L. both sides. no charger plug. no power on.


                    With charger, no power on:
                    PL102: 3.0v both sides
                    PL303: 0v both sides
                    PL302: 3.6 mV both sides
                    PLZ2: 0V both sides
                    PLG1: 0V both sides
                    PL1002: 0V both sides
                    PLM2: 0V both sides


                    When I press power button (what i can see on multimeter)
                    PL102: 3v both sides
                    PL303: 3.6v for a split of second
                    PL302: 5.19v for a split of second
                    PLZ2: around 100mV
                    PLG1: around 100mV
                    PL1002: 1.75v - 1.007 for a split of sec
                    PLM2: .381v for a split of second

                    Comment

                    • iplaypty
                      Member
                      • Aug 2017
                      • 47
                      • FLORIDA

                      #30
                      Re: HP 14, LA-A994P, charging light, power led on for 1 second when power button pres

                      Thank you very much tibd and ktmmotocross.

                      I was able to fix it.

                      I injected some amps on JPHW7 and found the bad cap next to UR1.

                      I removed it and now it turns on and show image on screen.

                      Is it important to place another cap there as replacement?

                      Thanks!
                      Attached Files

                      Comment

                      • ktmmotocross
                        Boardkiller
                        • Feb 2014
                        • 3553
                        • slovakia

                        #31
                        Re: HP 14, LA-A994P, charging light, power led on for 1 second when power button pres

                        Originally posted by iplaypty
                        Thank you very much tibd and ktmmotocross.

                        I was able to fix it.

                        I injected some amps on JPHW7 and found the bad cap next to UR1.

                        I removed it and now it turns on and show image on screen.

                        Is it important to place another cap there as replacement?

                        Thanks!
                        Never start without some component.

                        Yes replace it.

                        Comment

                        • ktmmotocross
                          Boardkiller
                          • Feb 2014
                          • 3553
                          • slovakia

                          #32
                          Re: HP 14, LA-A994P, charging light, power led on for 1 second when power button pres

                          looks like it is on pin 9 of UR1, which is +AVDD12 and thre are two capacitors CR3 and CR4

                          Comment

                          • tibd
                            Senior Member
                            • Oct 2014
                            • 189
                            • Sweden

                            #33
                            Re: HP 14, LA-A994P, charging light, power led on for 1 second when power button pres

                            Very good, and yes you need to replace that cap. Originally rated for 6.3v in parallel with a 16v cap (CR4). I would change with at least 10v-16 rating. As of capacitance same as original 4.7uf.

                            Comment

                            • iplaypty
                              Member
                              • Aug 2017
                              • 47
                              • FLORIDA

                              #34
                              Re: HP 14, LA-A994P, charging light, power led on for 1 second when power button pres

                              Originally posted by ktmmotocross
                              looks like it is on pin 9 of UR1, which is +AVDD12 and thre are two capacitors CR3 and CR4
                              ok, Thank you!

                              Comment

                              • iplaypty
                                Member
                                • Aug 2017
                                • 47
                                • FLORIDA

                                #35
                                Re: HP 14, LA-A994P, charging light, power led on for 1 second when power button pres

                                Originally posted by tibd
                                Very good, and yes you need to replace that cap. Originally rated for 6.3v in parallel with a 16v cap (CR4). I would change with at least 10v-16 rating. As of capacitance same as original 4.7uf.
                                ok, thank you!

                                Comment

                                • mainah njoroge
                                  Member
                                  • Aug 2017
                                  • 36
                                  • kenya

                                  #36
                                  Re: HP 14, LA-A994P, charging light, power led on for 1 second when power button pres

                                  I have the same problen did u get any solution

                                  Comment

                                  • mainah njoroge
                                    Member
                                    • Aug 2017
                                    • 36
                                    • kenya

                                    #37
                                    Re: HP 14, LA-A994P, charging light, power led on for 1 second when power button pres

                                    Originally posted by iplaypty
                                    I took some pictures with my phone.

                                    The owner of the laptop told me that he was using the computer, then it suddenly turned off.
                                    Did u manage the laptop because i have the same problem

                                    Comment

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