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Haier 7g-5h Plug in not charging, only charge when laptop power-off

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    Haier 7g-5h Plug in not charging, only charge when laptop power-off

    Hi to all ,

    i have Haier 7g-5h laptop, it does not charge while the laptop is power-on, it only charge when the laptop is power-off condition.

    any guidance, clue please.

    Schematic is attached page 29
    Attached Files
    Last edited by SMDFlea; 11-23-2021, 04:27 AM. Reason: Haier 7g-5h

    #2
    Re: Plug in not charging, only charge when laptop power-off

    1) see your schematic...

    2) remove all power. Meter in resistance mode. Check each mosfet starting at the entry of the adapter for defects.

    Resistance between

    source & drain
    Source & gate
    Gate & drain

    Low resistance may mean the mosfet is defective.

    http://electronicsbeliever.com/how-t...0good%20MOSFET.

    Is the power adapter the original?
    Last edited by mon2; 11-21-2021, 10:53 PM.

    Comment


      #3
      Re: Plug in not charging, only charge when laptop power-off

      Originally posted by mon2 View Post
      1) see your schematic...

      2) remove all power. Meter in resistance mode. Check each mosfet starting at the entry of the adapter for defects.

      Resistance between

      source & drain
      Source & gate
      Gate & drain

      Low resistance may mean the mosfet is defective.

      http://electronicsbeliever.com/how-t...0good%20MOSFET.

      Is the power adapter the original?
      thank you sir, but a little bit confusing about how to check resistance of mosfet. if suppose i set multimeter on 20K Ohm, then for example i get 10.3 on drain & source, but how gate & source and gate & drain as i got 0 value on both of them.
      charger is original

      Comment


        #4
        Re: Plug in not charging, only charge when laptop power-off

        Hi. The procedure is correct. Try the same on another mosfet. What is the result?

        The measured mosfet may be shorted and considered defective.

        The next step is to desolder off the logic board and test the removed mosfet when it is out of circuit. Are the measurements still reporting a very low resistance? If yes, replace the mosfet with a known good part.

        As noted, check other mosfets to see that the resistance should be higher for each pair of pins.

        Post the readings again for each mosfet.

        The 10.3 in 20k scale means 10k3 ohms resistance. But 0 means 0 ohms. Try a higher scale to confirm.

        Comment


          #5
          Re: Plug in not charging, only charge when laptop power-off

          Originally posted by mon2 View Post
          Hi. The procedure is correct. Try the same on another mosfet. What is the result?

          The measured mosfet may be shorted and considered defective.

          The next step is to desolder off the logic board and test the removed mosfet when it is out of circuit. Are the measurements still reporting a very low resistance? If yes, replace the mosfet with a known good part.

          As noted, check other mosfets to see that the resistance should be higher for each pair of pins.

          Post the readings again for each mosfet.

          The 10.3 in 20k scale means 10k3 ohms resistance. But 0 means 0 ohms. Try a higher scale to confirm.
          thanks sir, i'll check and report.

          but i want to ask what is/or should be the standard value of resistance (or can be known) for various components like mosfets, capacitos, resisters, coils etc
          or resistance from ground to any pin of any IC. (black prob on any ground and red on concern pin for getting some value, if i am right)

          2ndly the guide for testing mosfet says that for N-channel, if put red prob on gate and black on source, the MOSFET will turn-on and for P-channel black prob on gate and red on source the mos wil turn-on,
          so, the turning on does affect the measurement of resistance?
          Last edited by usyusy; 11-24-2021, 05:46 AM.

          Comment


            #6
            Re: Haier 7g-5h Plug in not charging, only charge when laptop power-off

            The resistance of a resistor will vary. The only accurate check is to compare against the schematic values. The resistance check can also be different while the component is onboard the logic board as compared to when it is removed. So for resistors, you can get a general idea by using a high resistance setting on your meter and keep reducing the setting to get a reading.

            If you have say 0 ohms for every setting, there is a short circuit. Much like touching the meter probes together = 0 ohms (typically).

            Resistors do not have a polarity so meter probe can be used in either direction.

            Same can be said about capacitors. Some capacitors are ceramic style which are NOT polarized. Tantalum and electrolytic types have a polarity. For this reason, the red meter probe must be on the '+' of the capacitor; black meter probe on ground. Again, the true capacitance value can be read only when the part is OFF the logic board.

            Capacitors in parallel are used to gang up and ADD up their values for a larger equivalent capacitance. This method is often used to filter switching power supply rails and to support higher current. As an analogy, if one person was to try to push a car = good luck. Yet, multiple people can work in parallel to push the car with ease. Same idea.

            Coils are just a long magnet wire across the 2 solder points. They should show very low resistance if not 0 ohms (use resistance mode to check if the coil is burnt or not). If the coil is burnt (very rare), the wire will be broken due to excessive heat = current = breaks. Then the resistance will be open or the meter will read OL = over limit.

            On the mosfet checking - review the direction of the arrow head in the center of the part. Once you know this direction, use the meter probes so that the mosfet does not turn on. The linked article shows the case when the mosfet will turn on so do the opposite. A damaged part will show low resistance between the test pins.

            Do review the sticky articles above this forum - for example the postings by @Piernov on how the switching power supplies work and what gets damaged. Often the first 2 DCIN mosfets get killed.

            Comment


              #7
              Re: Haier 7g-5h Plug in not charging, only charge when laptop power-off

              thanks sir for guidance.

              some readings of resistance are as given below along with voltages tests


              Resistence Check

              PQ19 => D-S …… 11.47 … on 20k
              PQ19 => G-D …… 0
              PQ19 => G-S …… 0

              PQ22 => 2-1 …… 18.75 … on 20k
              PQ22 => 2-6 …… 18.45
              PQ22 => 1-6 …… 0
              PQ22 => 5-4 …… 18.86
              PQ22 => 5-3 …… 18.68
              PQ22 => 3-4 …… 0

              PQ27 => D-S …… 0.533 … on 2K
              PQ27 => G-D …… 0
              PQ27 => G-S …… 0

              PQ2 => D-S …… 10.96 … on 20k
              PQ2 => G-D …… 0
              PQ2 => G-S …… 0

              PQ12 => D-S …… 0.588 … on 2K
              PQ12 => G-D …… Rising values
              PQ12 => G-S …… 6.11 … on 20k

              PQ8 => D-S …… 1.7 … on 20k
              PQ8 => G-D …… 0.145 … on 2M
              PQ8 => G-S …… 0

              PQ7 => D-S …… 0.671 … on 2K
              PQ7 => G-D …… 0
              PQ7 => G-S …… Rising values

              PQ9 => 2-1 …… 17.81 … on 20k
              PQ9 => 2-3 …… 16.5
              PQ9 => 3-1 …… 0

              Comment


                #8
                Re: Haier 7g-5h Plug in not charging, only charge when laptop power-off

                Voltage check

                PQ19 => D … 20 V
                PQ19 => S … 20
                PQ19 => G … 16.*

                PQ22 => 1 … 19.46 V
                PQ22 => 2 … 18.92
                PQ22 => 3 … 16.74
                PQ22 => 4 … 18.87
                PQ22 => 5 … 18.27
                PQ22 => 6 … 19.46

                PQ27 => 1 … 0 V
                PQ27 => 3 … 19.46
                PQ27 => 4 … 19.46

                PQ2 => S … 2.71 V
                PQ2 => G … 2.71
                PQ2 => D … 19.48

                PQ12 => D … 19.46 V
                PQ12 => S … 2.7
                PQ12 => G … 2.7

                PQ8 => D … 2.7
                PQ8 => S …
                PQ8 => G …

                PQ7 => S (1) … 0
                PQ7 => G (2) … 0.03
                PQ7 => D (3) … 2.37

                PQ9 => 1 … 0
                PQ9 => 2 … 0.58
                PQ9 => 3 … 0.03

                PQ13 => S (1) … 0
                PQ13 => G (2) … 0
                PQ13 => D (3) … 2.7

                Comment


                  #9
                  Re: Haier 7g-5h Plug in not charging, only charge when laptop power-off

                  Battery Connector voltages

                  Pin 1 => 2.72 V
                  2 => 2.72
                  3 => 3.3
                  4 => 3.3
                  5 => 0
                  6 => 0.04
                  7 => 0
                  8 => 0

                  Comment


                    #10
                    Re: Haier 7g-5h Plug in not charging, only charge when laptop power-off

                    Laptop On, battery attached but not charging.
                    charging IC pin voltages are as under


                    ACN (Pin 1) => 19.54 V
                    ACP (2) => 19.54
                    CMSRC (3) => 19.44
                    ACDRV (4) => (1)
                    ACPRES (5) => 2.88

                    ACDET (6) => 2.57
                    IOUT (7) => 0.08
                    SDA (8) => 3.34
                    SCL (9) => 3.34
                    ILIM (10) => 0.04

                    BATDRV (11) => 16.62
                    SRN (12) => 16.73
                    SRP (13) => 16.73
                    GND (14) => 0
                    LODRV (15) => 0

                    REGN (16) => 6.06
                    BTST (17) => 16.31
                    HIDRV (18) => 16.73
                    PHASE (19) => 16.73
                    VCC (20) => 19.53

                    Comment


                      #11
                      Re: Haier 7g-5h Plug in not charging, only charge when laptop power-off

                      Assorted readings do not look correct but let us start with ILIM on the charger IC.

                      Pin # 10 of this Texas Instruments charger IC is linked to 2 resistors that act like a voltage divider. The voltage @ pin #10 should be ~1v5 since both resistors are the same value and the high side resistor (PR37) is mated to +3v0.

                      Based on the calculations, pin #10 should be ~50% of the pull-up resistor voltage.

                      So,

                      1) confirm the voltage again @ pin #10 of the charger IC PU2. Is it not equal to about +1v5 ?

                      2) Next, confirm that PR37 has about +3v0 on one side of the resistor.

                      If not, then +3VPCU may be missing or not enabled.

                      Post your readings.

                      Comment


                        #12
                        Re: Haier 7g-5h Plug in not charging, only charge when laptop power-off

                        Originally posted by mon2 View Post

                        So,

                        1) confirm the voltage again @ pin #10 of the charger IC PU2. Is it not equal to about +1v5 ?

                        2) Next, confirm that PR37 has about +3v0 on one side of the resistor.

                        If not, then +3VPCU may be missing or not enabled.

                        Post your readings.
                        You are absolutely right sir,

                        When laptop powered-on (with charger and battery both attached)

                        1) pin 10 of IC shows same as 0.04 V

                        2) PR37 both side values are 0.04

                        (Moreover pr38 seems to be not present)
                        Attached Files
                        Last edited by usyusy; 11-26-2021, 10:41 AM.

                        Comment


                          #13
                          Re: Haier 7g-5h Plug in not charging, only charge when laptop power-off

                          1) PR38 may be a no stuff on the PCB since the PR38 has a '*' prefix. Every vendor has their own kooky system on what part should be a stuff or no stuff during the PCB assembly process. For HP, usually the '@' means = do not stuff the part.

                          I think for PR38, for now, it is a no stuff.

                          2) However, the +3VPCU on PR37 is required.

                          3) +3VPCU is created by the internal LDO (pin_8) inside of PU9.

                          Measure and post the voltage of

                          a) pin #8 (+3VPCU) of PU9

                          b) pin # 13 of PU9 (this pin must be a logic '1' = high to enable the 3V & 5V LDO regulators inside PU9)

                          c) pin # 16 of PU9

                          d) pin # 17 of PU9

                          Comment


                            #14
                            Re: Haier 7g-5h Plug in not charging, only charge when laptop power-off

                            Originally posted by mon2 View Post
                            1)

                            Measure and post the voltage of

                            a) pin #8 (+3VPCU) of PU9

                            b) pin # 13 of PU9 (this pin must be a logic '1' = high to enable the 3V & 5V LDO regulators inside PU9)

                            c) pin # 16 of PU9

                            d) pin # 17 of PU9
                            Got your excellent point sir,
                            As directed the report is as under: PU9

                            a) pin # 8 => 3.39v
                            b) pin # 13 => 2.35v (when I touch probe on this pin to measure volts, laptop gets-off, so it's the value when the laptop is off i.e. 2.35v)
                            c) pin # 16 => 19.55v
                            d) pin # 17 => 5.17v
                            Attached Files
                            Last edited by usyusy; 11-27-2021, 02:09 AM.

                            Comment


                              #15
                              Re: Haier 7g-5h Plug in not charging, only charge when laptop power-off

                              1) good that you have +3VPCU working on pin #8 of PU9.

                              2) confirm again that PR37 has one side of the resistor going to pin #10 (ILIM) of the charger IC.

                              The other side of PR37 should be a direct connection to +3VPCU. But earlier test show that it is not.

                              Check these connections with no power to the logic board, meter in 2K resistance mode.

                              Is there no connection from PR37 to the +3VPCU pin of PU9 ?

                              3) next confirm the resistance of PR37. It should be about 100K. The value is not really critical since the pull down at PR38 is missing. So ILIM should be about 3V if all is well.

                              If PR37 has no connection to +3VPCU, then there appears to be a broken pcb trace. You will have to solder the floating side of PR37 to the +3VPCU with a wire to fix this missing connection.

                              Fix this issue and test again. Post your updates.

                              Comment


                                #16
                                Re: Haier 7g-5h Plug in not charging, only charge when laptop power-off

                                Thanks so sir,
                                as your goodself directed, the findings are as under:

                                2) PR37 has one side connectivity to ILIM pin # 10 of the charger IC (beep mode).
                                there was no connection from PR37 to the +3vPCU pin#8 of PU9.

                                3) the resistance of pr37 could not be measured. however, as you supposed that there appeared to be a broken pcb trace, it seemed to be true.

                                so i jumpered from a nearby capacitor (PC209) of PU9 +3VPCU to PR37 other side, thus getting about 3.0v on pin #10 (ILIM) of charging IC.

                                BATTERY STARTED TO CHARGE WHEN LAPTOP WAS ON!

                                All thanks to your excellent tips, tricks and guidance in which many unknown points were learned.

                                earlier i search for +3VPCU, about half of the board missing +3VPCU like power button connector pin 1, near keyboard points, battery connector pin 6 for (B_TEMP_MBAT)

                                i wonder B_TEMP_MBAT, pin 6 of battery connector should not have any value? just 0.04v was coming on it.
                                Last edited by usyusy; 11-27-2021, 12:18 PM.

                                Comment


                                  #17
                                  Re: Haier 7g-5h Plug in not charging, only charge when laptop power-off

                                  Well done !!
                                  the resistance of pr37 could not be measured.
                                  This should be possible but guessing that the scale setting of your multimeter was too low. Since we know in advance that the resistance of PR37 should be about 100k ohms, use a scale that can measure this value (or higher but not lower).

                                  It is also possible that the resistor could have been damaged so even after this wire repair, the ILIM would remain to be 0V (approx) = useless for the charging issue. The higher this analog voltage value, the more current the charger IC can supply or allow to pass onto the battery for charging. Once this threshold is reached (breached), stop the charging process. Again, @ 0V, nothing to do. The TI datasheet offers full details on how this works. Respectively other brand of charger ICs will work in a similar fashion.

                                  So the take away here (and for future readers), the ILIM appears to have been the key fault and this analog voltage should be a non-zero value. For your case, it was @ 0V which effectively tells the charger IC that there is nothing to do. The TI (Texas Instruments) datasheet was very helpful in telling us the list of requirements before the charger IC will enable to charge the target battery.

                                  This analog voltage is decided by the 2 resistor based voltage divider. For your logic board, it appears that the designers wanted to just use the max current = +3v (approx). Once this missing voltage rail was restored, your battery started to charge like normal.

                                  i wonder B_TEMP_MBAT, pin 6 of battery connector should not have any value? just 0.04v was coming on it.
                                  On the B_TEMP_MBAT observation, see attached.

                                  Check that the +3VPCU is present on one side of the resistor @ PR3.

                                  Remove the battery for these tests.

                                  Use your multimeter in 2k scale or even diode mode is ok.

                                  The meter should beep when you connect the probe to PR3 (one side) & pin 6 of the battery connector on the other side.

                                  Then test the other side of PR3 and be sure it connects to the +3VPCU rail @ +3v. If not, this is required.

                                  Guessing that some minor liquid damage caused corrosion on your logic board and caused a disconnect of the +3VPCU rail for certain parts.

                                  As a precaution, thoroughly test the board and also check for the presence of the +3VPCU across the circuits.
                                  Attached Files

                                  Comment


                                    #18
                                    Re: Haier 7g-5h Plug in not charging, only charge when laptop power-off

                                    Learned it sir, thank you for your in-depth knowledge sharing

                                    Comment

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