Asus K43U LA-7321P power sequence issue

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • jeremykum
    Senior Member
    • Feb 2012
    • 95
    • Malaysia

    #1

    Asus K43U LA-7321P power sequence issue

    Hi everyone,

    I need some guidance here. Hope someone can offer some explanation, out of ideas.

    I have this problem with this board LA-7321P from Asus K43U.

    If I insert charger first, then battery, the system is charging normally, and if I pulled out the charger, it will switch to battery power.

    But if I insert back the charger, I have a short at my amp meter, goes from 0 to 2.3A and keep repeating, means power from charger is auto cut off. The system still functions though, windows won't shut down. It is still powering from battery and doesn't charge.

    In short, the system must receive power from charger first. If Battery is inserted first, the supply doesn't switch over to Charger and battery doesn't charge.

    I do suspect somebody else had caused some damages trying to repair this laptop. There is a bypass for direct power supply to the LVDS connector.
    I already removed the bypass wire but system power is still the same symptom. I did measure the power supplied at the LVDS connector, if system in only from AC (charger), I get 18+v. If only from battery I get 12+v (only at standby, I didn't power on the board)

    Here I included a schematic, refer to pg36. Hope someone can offer some guidance where should I check when charger inserted but system doesn't switch its power to AC.
    Attached Files
    Mainly repair laptops, sometimes LCD/LED monitors. Also accepts changing/reballing/reflow BGA job request.
  • khaahk
    Badcaps Veteran
    • Dec 2013
    • 745
    • Estonia

    #2
    Re: Asus K43U LA-7321P power sequence issue

    Voltages on PQ102 & PQ103 gates are doing what when the charger is auto cut-off?

    Comment

    • jeremykum
      Senior Member
      • Feb 2012
      • 95
      • Malaysia

      #3
      Re: Asus K43U LA-7321P power sequence issue

      Originally posted by khaahk
      Voltages on PQ102 & PQ103 gates are doing what when the charger is auto cut-off?
      Alrite, took some measurements.

      AC only
      PQ102 - pin1-8 18.38V
      PQ103 - pin1-4 18.38V, pin5-8 18.97V

      Bat Only
      PQ102 - pin1-8 12.43V
      PQ103 - pin1-4 12.43V, pin5-8 0V

      Bat inserted, then follow with AC-in (charger)
      PQ102 - pin1-8 12.43V may skip to 13.xxV occasionally
      PQ103 - pin1-4 12.43V may skip to 13.xxV occasionally
      PQ103 - pin5-8 jumping between 10.xxV - 13.xxV

      BTW, now I am powering with a Acbel adapter rated 65W attached to a Kyoritsu Ammeter.

      Ampere reading from 0.001- 0.002 jump to 1.700 to 0.000 to 0.001 to 0.307.
      It's just showing me power circuit problem.

      Normal standby (battery removed) is 0.018A

      Hope this helps...
      Thanks for the help in advance.
      Mainly repair laptops, sometimes LCD/LED monitors. Also accepts changing/reballing/reflow BGA job request.

      Comment

      • paulstef
        Badcaps Veteran
        • Dec 2013
        • 724
        • Canada

        #4
        Re: Asus K43U LA-7321P power sequence issue

        Originally posted by jeremykum
        PQ103 - pin1-4 12.43V may skip to 13.xxV occasionally

        So this would be always ON. Meaning the path from B+ to BATT is correct for charging.

        With the error present what is the voltage at VIN, P2 and P3? That's around PQ101, PQ102. Measuring to ground.

        Then what is the voltage VGS of PQ101 and PQ102? You only gave us VDS of PQ102.

        Comment

        • khaahk
          Badcaps Veteran
          • Dec 2013
          • 745
          • Estonia

          #5
          Re: Asus K43U LA-7321P power sequence issue

          I would first try another ac adapter. Or the charging circuit (ic?) is not working correctly. PIN2 (ACSET) of ISL6251 is stable?

          Comment

          • atsio
            Badcaps Veteran
            • Oct 2013
            • 819
            • Greece

            #6
            Re: Asus K43U LA-7321P power sequence issue

            PQ101, PQ102, PQ103 are PNP FETS and gate (pin 4) should be low(locked in "protected mode"). Check resistance to ground on pins 1,2,3 of PQ101 and PD101. Check also PQ101, PQ102 and PQ103 if OK. If all OK measure voltage on all pins of charger and report.

            Comment

            • jeremykum
              Senior Member
              • Feb 2012
              • 95
              • Malaysia

              #7
              Re: Asus K43U LA-7321P power sequence issue

              Alrite, will check it later, need to go out deliver stuffs to client.
              Mainly repair laptops, sometimes LCD/LED monitors. Also accepts changing/reballing/reflow BGA job request.

              Comment

              • jeremykum
                Senior Member
                • Feb 2012
                • 95
                • Malaysia

                #8
                Re: Asus K43U LA-7321P power sequence issue

                I am sorry for the late reply, had a busy day with many laptops coming in.

                Now I manage to get some readings as requested;

                atsio:
                Battery pin when only charger inserted.
                1 & 2 = 18.36v keep dropping
                3 & 4 = 0v
                5 & 6 = 3.327v
                7 = 3.293v
                8 & 9 = 0v

                Is it Pin 1 & 2 should be steady at 18.36v (same as my input voltage)?

                PQ101 pin 1-3 to ground 33.2Kohm
                Checked all Source/Drain/Gate of PQ101/102/103 should be fine, all above 50ohm

                PD101 1way 0.227v, reverse 0v
                Ohm to ground 88.2Kohm and 136.4Kohm

                Khaahk:
                Adapter isn't an issue so far, I can confirm.

                Pin2 ACSET ISL6251 when error is 0.6-0.8v jumping. Normal gives me 1.381V

                Paulstef:
                I am sorry, I couldn't get what exactly you mean by VGS?

                When error;
                VIN = 9.46-11.24V jumping up and down
                PQ101 pin 5-8, I get 11.42V, and this I measure the battery voltage, it's the same.

                Alrite, I think I explain the sequence.
                Adapter plug in, then battery, it works fine.
                I remove the adapter, it still powering the laptop.
                I reinsert the adapter, my amp meter goes haywire, but laptop is still working fine from battery power.

                Thanks in advance for the advice and your time here.
                Mainly repair laptops, sometimes LCD/LED monitors. Also accepts changing/reballing/reflow BGA job request.

                Comment

                • paulstef
                  Badcaps Veteran
                  • Dec 2013
                  • 724
                  • Canada

                  #9
                  Re: Asus K43U LA-7321P power sequence issue

                  Originally posted by jeremykum

                  Paulstef:
                  I am sorry, I couldn't get what exactly you mean by VGS?

                  When error;
                  VIN = 9.46-11.24V jumping up and down
                  PQ101 pin 5-8, I get 11.42V, and this I measure the battery voltage, it's the same.

                  VGS = voltage from gate to source
                  VDS = voltage from drain to source

                  This measurement is weird. On the schematic VIN = 5-8 of PQ101. I assume you meant you measure battery voltage on pins 1-3 of PQ101?

                  Comment

                  • jeremykum
                    Senior Member
                    • Feb 2012
                    • 95
                    • Malaysia

                    #10
                    Re: Asus K43U LA-7321P power sequence issue

                    Originally posted by paulstef
                    VGS = voltage from gate to source
                    VDS = voltage from drain to source

                    This measurement is weird. On the schematic VIN = 5-8 of PQ101. I assume you meant you measure battery voltage on pins 1-3 of PQ101?
                    Yes VIN = pq101 pin 5-8, should show my adapter voltage whenever adapter is inserted right?

                    What i meant was pin 5-8 shows voltage that is same as the battery output voltage.

                    Because there are a lot of plastic parts nearby this section, hot air blower to remove isl6251 isn't an option. And if I am not pretty sure if isl6251 is the culprit i would avoid putting this board in my IR rework station.
                    Mainly repair laptops, sometimes LCD/LED monitors. Also accepts changing/reballing/reflow BGA job request.

                    Comment

                    • atsio
                      Badcaps Veteran
                      • Oct 2013
                      • 819
                      • Greece

                      #11
                      Re: Asus K43U LA-7321P power sequence issue

                      Cover them with karton tape and then aluminium. It should be allright.

                      Comment

                      • jeremykum
                        Senior Member
                        • Feb 2012
                        • 95
                        • Malaysia

                        #12
                        Re: Asus K43U LA-7321P power sequence issue

                        Originally posted by atsio
                        Cover them with karton tape and then aluminium. It should be allright.
                        This will be a challenge to wrap it
                        Still have some new ISL6251, I will try replace it and see what happens. Update later.
                        Attached Files
                        Mainly repair laptops, sometimes LCD/LED monitors. Also accepts changing/reballing/reflow BGA job request.

                        Comment

                        • paulstef
                          Badcaps Veteran
                          • Dec 2013
                          • 724
                          • Canada

                          #13
                          Re: Asus K43U LA-7321P power sequence issue

                          Originally posted by jeremykum
                          This will be a challenge to wrap it
                          Still have some new ISL6251, I will try replace it and see what happens. Update later.
                          A tweezer soldering iron works great for SOIC-8.

                          Comment

                          • jeremykum
                            Senior Member
                            • Feb 2012
                            • 95
                            • Malaysia

                            #14
                            Re: Asus K43U LA-7321P power sequence issue

                            Yup SOIC8 I use a knife type solder tip and a tweezer.

                            Replaced ISL6251, same problem.
                            Got so annoyed, fix up the laptop again, power the adapter then insert battery. Reinstall Windows, disable all windows power saving feature and ran it till morning. Guess what, now whenever I reinsert the charger, the laptop respond normal doesn't matter in windows or after I shutdown the windows.
                            Mainly repair laptops, sometimes LCD/LED monitors. Also accepts changing/reballing/reflow BGA job request.

                            Comment

                            Related Topics

                            Collapse

                            • flat-earther
                              ASUS X54H laptop thinks it's always charging even with charger unplugged
                              by flat-earther
                              The charging indicator light on my ASUS X54H laptop is always on even when the charger is disconnected.

                              Windows also shows ''Plugged in'' when charger is not connected.

                              This problem started year ago gradually, when unplugging the charger the charging light took several seconds to disappear, then minutes, and now almost always on even when unplugged for an entire day.
                              Strangely, before sometimes immediately when plugging in the charger the charging light went away, and later came back with it connected.
                              If I let battery run out and say it has 3% Windows will...
                              06-24-2025, 09:32 AM
                            • motormayhem
                              Lenovo T460 Only Charges on One Charger
                              by motormayhem
                              Laptop Question
                              Hello,
                              I'm working on a Lenovo T460 that has been having trouble charging as of late. Its worked well since I've owned it for a few years. When I went to use it the other day it was dead and wouldn't turn on (was sitting on an Anker 65W GaN charger). After some fiddling with the charger I got it to turn on and start charging, but seemed like the charger was not working as it should (took a few plug and unplug cycles to get it to start charging).

                              A day later it was dead again and wouldn't boot/charge no matter what I did. No lights or anything when...
                              05-12-2023, 01:46 PM
                            • Document Archive
                              ISL88739AHRZ ISL88739 Laptop Battery Charger Datasheet
                              by Document Archive
                              The ISL88739 & ISL88739AHRZ are a highly versatile combo battery charger
                              configurable for operating as either a Hybrid Power Boost (HPB)
                              charger or a Narrow VDC (NVDC) charger, supporting 2-, 3-, or
                              4-cell batteries. Both configurations allow the battery to work with
                              the adapter together to supply the system load when it exceeds
                              the adapter capability, referred to as system Turbo mode. HPB
                              charger configuration reverse-boosts battery energy to the system
                              bus to help the adapter provide the system power in Turbo mode.
                              NVDC charger configuration...
                              11-05-2024, 03:28 PM
                            • Johndill
                              Dell Inspiron 7567 LA-D993P odd charger issue
                              by Johndill
                              Hi, I have a Dell Inspiron 7567 LA-D993P that I've just got running.
                              There was corrosion around PU1503 which shorted PC1518 & blew PL1504. (Reference pictures attached)
                              I've replaced PC1518 & PL1504 & the laptop is now running however I now have another issue.

                              Here are the tested scenarios:

                              1. With the laptop running on battery, I plug in the 150W charger & the charger shuts off (no LED, protection mode) but the laptop remains running on battery.

                              2. With the laptop off, plug in charger (LED says on) & the front charging...
                              11-16-2022, 10:55 PM
                            • Document Archive
                              ISL6257HRZ ISL6257HRZ-T Laptop Battery Charger Datasheet
                              by Document Archive
                              ISL6257HRZ ISL6257HRZ-T Laptop Battery Charger Datasheet

                              Highly Integrated Narrow VDC Battery Charger for Notebook Computers

                              The ISL6257HRZ ISL6257HRZ-T is a highly integrated battery charger controller
                              for Li-Ion/Li-Ion polymer batteries. ISL6257 is designed for
                              Narrow VDC applications where the system power source is
                              either the battery pack or the regulated output of the charger.
                              This makes the max voltage to the system equal to the max
                              battery voltage instead of the max adapter voltage. Operating
                              at lower system voltage can improve...
                              11-05-2024, 04:43 PM
                            • Loading...
                            • No more items.
                            Working...