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Lenovo Ideapad 330S-14IKB Not Powering On

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    #1

    Lenovo Ideapad 330S-14IKB Not Powering On

    Lenovo Ideapad 330S-14IKB Model: 81F4
    Motherboard: 330S_KBL_MB_V09 Rev: MP (PN: 431204237090) (5B20S69494)

    Has been working till now for two months after cleaning water damage.
    Problem: does not power on. No consumption.
    19-20V present.
    3.3V and 5V not present.
    No power around EC.
    Missing ILIM, ACOK... on the charger. No EN nor PGOOD on the 3/5V power supplies.

    Charger BQ24780SRUYT (U5901):
    <1>ACN: 19.78V
    <2>ACP: 19.78V
    <3>CMSRC: 19.68V
    <4>ACDRV: 24.6V
    <5>ACOK: 0.01V
    <6>ACDET: 2.36V
    <7>IADP: 0V
    <8>IDCHG: 0V
    <9>PMON: 0V
    <10>PROCHOT/: 0.26V
    <11>SDA: 0.01V
    <12>SCL: 0.01V
    <13>CMPIN: 0V
    <14>CMPOUT: NC
    <15>BATPRES/: 0V
    <16>TB_STAT/: 0.01V
    <17>BATSRC: 0.22V
    <18>BATDRV: 0.24V
    <19>SRN: 0.22V
    <20>SRP: 0.22V
    <21>ILIM: 0V-0.003V
    <22>GND: 0V
    <23>LODRV: 0V
    <24>REGN: 5.95V
    <25>BTST: 5.62V
    <26>HIDRV: 0.21V
    <27>PHASE: 0.22V
    <28>VCC: 19.51V

    +V5P0A power supply (U6001):
    <1>BOOT: 0.005V
    <2>LX1: 0.018V
    <3>LX2: 0.018V
    <4>PGND: 0V
    <5>VIN: 19.80V
    <6>EN: 0.016V
    <7>PGOOD: 0.017V
    <8>AGND: 0V
    <9>VCC: 0.017V
    <10>VOUT: 0.017V
    <11>LDO: 0.010V
    <12>CLK: 0.014V

    +V3P3A power supply (U6002):
    <1>BOOT : 0V
    <2>LX1 : 0V
    <3>LX2 : 0V
    <4>PGND : 0V
    <5>VIN : 19.79V
    <6>EN : 0.009V
    <7>PGOOD: 0V
    <8>AGND : 0V
    <9>VCC : 0V
    <10>VOUT: 0V
    <11>BYP : 0.018V
    <12>ILMT: 0.021V

    I don't have the schematic/boardview for the exact model but for a similar one: schematic, boardview.
    Any pointers where to start? Bear in mind I'm a novice.
    Attached Files
    Last edited by electrocute; 09-24-2021, 02:24 PM.
    Tags: None
    #2
    Re: Lenovo Ideapad 330S-14IKB Not Powering On

    Hi.

    1) U6001, LDO should supply @ +3v3 rail = always ON and is not linked to the EN pin # 6 as this is the "C" version of the switching regulator.

    2) Remove all power - meter in resistance mode. Check the resistance to ground on each and every coil. Looking for super low resistance readings which may offer a clue on what is going on for this board.

    3) Any new liquid damage ? Perhaps consider to flux and reflow U6001.

    The +V3.3AL on pin # 6 is required to support many key components on the logic board including I2C bus and other pull-ups, power the EC, etc.

    Comment

      #3
      Re: Lenovo Ideapad 330S-14IKB Not Powering On

      Thanks for the prompt reply.
      2)
      Here are the measurements (same order as in screenshot/boardview, from left to right, top to bottom)
      L6300: 0V 35.1 Ω
      L6703: 0V 12.8 Ω
      L6701: 0V 4.7 Ω
      L6704: 0V 4.7 Ω
      L6702: 0V 6.7 Ω

      L5901: out of scale (showing 1. on 20MΩ scale)
      L6001: 0.017V 20.3 Ω
      L6002: 0V 7.92 kΩ and raising up
      L6100: 0V 120 Ω

      Using a manual range DMM.

      3) no new liquid damaged reported or observed. Will try to reflow U6001 on monday.

      Comment

        #4
        Re: Lenovo Ideapad 330S-14IKB Not Powering On

        Coil readings look ok. Low voltage rails will have low resistance values.

        Power down and check the resistance of each mosfet starting with Q5901 & Q5902. Often one of these bad boys get nuked to halt the party.

        ACOK = logic LOW = power good indicator. However, this open-drain pin will only present a HIGH if the +V3.3AL (+V3P3A_EC) is working which it is not...

        Comment

          #5
          Re: Lenovo Ideapad 330S-14IKB Not Powering On

          @mon2, coil readings dont look good to me. L6001 is for +5V rail and resistance is 20.3 Ohms. Clearly shorted. Seems like you missed it.

          Comment

            #6
            Re: Lenovo Ideapad 330S-14IKB Not Powering On

            @mon2, coil readings dont look good to me. L6001 is for +5V rail and resistance is 20.3 Ohms. Clearly shorted. Seems like you missed it.
            Yes! Thanks for the correction.

            1) Remove R10860.

            2) Remove all power. Meter in resistance mode. Check and post the resistance to ground on R10860, each SMD pad. We wish to check where the short resides - is it on the side that creates this voltage rail OR the side that consumes this voltage rail?

            It is quite possible that U6001 (RT6228CGQUF) may need to be replaced due to this event.

            Good idea to grab a few of these for the toolbox. The "C" suffix is very important on this component.

            Datasheet is attached.

            https://www.aliexpress.com/wholesale...psort=1&page=1
            Attached Files

            Comment

              #7
              Re: Lenovo Ideapad 330S-14IKB Not Powering On

              R10860 = solder blow.
              14 Ω on the side of the +V5 power supply. (so short on this side)
              1.55 MΩ on the +V5CP side.

              Comment

                #8
                Re: Lenovo Ideapad 330S-14IKB Not Powering On

                14 Ω on the side of the +V5 power supply. (so short on this side)
                Yes indeed.

                See attached. Lift up one side of L6001. Then check the resistance again -> still 14 ohms ?

                If yes, then it is down to the highlighted caps in the box.

                Consider to remove each of the caps from the logic board and test the resistance again.

                If you wish, you can certainly remove one cap at a time -> check the resistance -> repeat if required.

                Suspecting it is one of the 22uf caps but you can also remove the 0.1uf.

                Edit: C6014 & C6015 = NI = Not installed (?) so the cap check list is even shorter...
                Attached Files
                Last edited by mon2; 09-25-2021, 12:30 PM.

                Comment

                  #9
                  Re: Lenovo Ideapad 330S-14IKB Not Powering On

                  Thanks. Will try on monday.
                  Originally posted by mon2 View Post
                  C6014 & C6015 = NI = Not installed (?) so the cap check list is even shorter...
                  Yes, there are no components on those, only the pads.

                  Comment

                    #10
                    Re: Lenovo Ideapad 330S-14IKB Not Powering On

                    Thanks. Will try on monday.
                    Originally posted by mon2 View Post
                    C6014 & C6015 = NI = Not installed (?) so the cap check list is even shorter...
                    Yes, there are no components on those, only the pads.
                    Originally posted by electrocute View Post
                    R10860 = solder blow.
                    solder blob!

                    Comment

                      #11
                      Re: Lenovo Ideapad 330S-14IKB Not Powering On

                      Same after lifting up one side of L6001 and after removing the caps. That leaves pin 10 (VOUT) on U6001 so the 5V power supply seems bad, at least, and needs to be replaced.

                      Comment

                        #12
                        Re: Lenovo Ideapad 330S-14IKB Not Powering On

                        Yes, if the external caps have been ruled out then through process of elimination, U6001 needs to be replaced.

                        If there is any doubt, consider to flux & reflow u6001 to make it 'dance' for good solder joints. Check the resistance again but sounds like this regulator is damaged. Best to order some spares in case this issue repeats.

                        Comment

                          #13
                          Re: Lenovo Ideapad 330S-14IKB Not Powering On

                          Is there anything else to check at this point (without having the replacement part) to rule out other problems on the board?
                          Last edited by electrocute; 09-27-2021, 10:59 AM.

                          Comment

                            #14
                            Re: Lenovo Ideapad 330S-14IKB Not Powering On

                            It's the Controller 99,99%. Replace it. Everything Else Looks fine now.
                            FairRepair on YouTube

                            Comment

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