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B+ Voltage rail; Lenovo Y510p VIQY1 NM-A032

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    #21
    Re: B+ Voltage rail; Lenovo Y510p VIQY1 NM-A032

    What are the voltage readings of pin # 4 (gate) on:

    PQ301

    PQ302


    - check both with the adapter connected - no battery.

    Also check and post the readings @

    PQ301 - pins 1-2-3 (any of these pins is ok for the measurement)

    Comment


      #22
      Re: B+ Voltage rail; Lenovo Y510p VIQY1 NM-A032

      Both gates PQ301 and PQ302 are 19,5V.
      PQ301 input: 20V, output 19,5V;
      PQ302: input: 19,5V, output 0,8V.

      Comment


        #23
        Re: B+ Voltage rail; Lenovo Y510p VIQY1 NM-A032

        Waiting for any ideas :<
        My idea was to try maybe trace the PGood status of PU301, but im not sure where and what to look for...

        Comment


          #24
          Re: B+ Voltage rail; Lenovo Y510p VIQY1 NM-A032

          Both PQ301 & PQ302 are P-channel mosfets.

          With P-channel mosfets, the GATE must be lower than the voltage being passed between source & drain. If you are measuring 19v @ the gate pin # 4, then the mosfet should be OFF.

          PQ302 appears to be OFF and this is expected.

          PQ301 appears to be full ON - incorrect for P-channel.

          Confirm the voltages on PQ301 again - source; drain; gate.

          Was this part replaced and soldered on in the same orientation ?

          It appears to be leaking if source & drain are at the same voltage yet GATE = 19v.

          Check with removing all power. Wait a minute to allow for discharge of the caps.

          Meter in resistance mode - check the resistance across the pins like before:

          source (1-2-3) & drain (5-6-7-8)
          source (1-2-3) & gate (4)
          gate (4) & drain (5-6-7-8)


          Post the readings.

          Comment


            #25
            Re: B+ Voltage rail; Lenovo Y510p VIQY1 NM-A032

            Picture with voltage measurements in attachment.
            The second schematic screenshot shows the gate for PQ301. If I have 19,5V on gate there, then something attached to it should give 19,5V right? Either Green line, Yellow line, or from the mosfet itself (which shoudln't happen given the resistances from before right?)
            Attached Files

            Comment


              #26
              Re: B+ Voltage rail; Lenovo Y510p VIQY1 NM-A032

              If I have 19,5V on gate there, then something attached to it should give 19,5V right?
              No. This is a P-channel mosfet so the gate has to be sufficiently negative or lower than the voltage INPUT to enable the mosfet.

              You have ~20 V as input and ~19v5 as the output with the gate @ 19v5 which is not low enough on the gate pin to turn on this mosfet.

              Do you have another P-channel mosfet you can use to replace PQ301 ?

              Comment


                #27
                Re: B+ Voltage rail; Lenovo Y510p VIQY1 NM-A032

                Originally posted by mon2 View Post
                No. This is a P-channel mosfet so the gate has to be sufficiently negative or lower than the voltage INPUT to enable the mosfet.

                You have ~20 V as input and ~19v5 as the output with the gate @ 19v5 which is not low enough on the gate pin to turn on this mosfet.

                Do you have another P-channel mosfet you can use to replace PQ301 ?
                This is happening perhaps as first dc in fet is working in diode mode due to improper biasing of gate voltage. The mosfet itself is unlikely to be bad.

                Comment


                  #28
                  Re: B+ Voltage rail; Lenovo Y510p VIQY1 NM-A032

                  So, what do You suggest mcplslg123 ?

                  Comment


                    #29
                    Re: B+ Voltage rail; Lenovo Y510p VIQY1 NM-A032

                    Originally posted by mcplslg123 View Post
                    This is happening perhaps as first dc in fet is working in diode mode due to improper biasing of gate voltage. The mosfet itself is unlikely to be bad.
                    Shouldnt PQ303 be bringing the PQ301 gate voltage down and to do that PQ304 should be switched on.The PQ301 gate voltage should be at least 5V lower ?
                    Last edited by SMDFlea; 05-24-2022, 08:22 AM.
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                    Comment


                      #30
                      Re: B+ Voltage rail; Lenovo Y510p VIQY1 NM-A032

                      I've removed the PQ303 and measured its resistance:
                      Pin 1 - IN; 2 -GND; 3-OUT
                      1-2 95 KOhms no matter the polarisation
                      1-3 6,75 MOhms with red on 1; no reading opposite
                      2-3 6,75 MOhms with red on 2; no reasing opposite
                      In diode mode: no reading no matter which pin and which polarisation.
                      Quick google for schematic and added it in attachement.
                      Attached Files

                      Comment


                        #31
                        Re: B+ Voltage rail; Lenovo Y510p VIQY1 NM-A032

                        Originally posted by ITworkshop View Post
                        So, what do You suggest mcplslg123 ?
                        Remove both PQ303 & PQ304 and power up. Check Readings on PQ301/PQ302 again. It wont harm you to apply power without PQ303/304 as they are just protection circuit.

                        Comment


                          #32
                          Re: B+ Voltage rail; Lenovo Y510p VIQY1 NM-A032

                          After desoldering PQ303 and PQ304, small difference in voltage at the gates - 19,18V not 19,5V - screenshot in attachment.
                          So do You think the culprit could be the PU301?
                          Attached Files

                          Comment


                            #33
                            Re: B+ Voltage rail; Lenovo Y510p VIQY1 NM-A032

                            Post the measurements for points # 1 & # 2 of the attached.
                            Attached Files

                            Comment


                              #34
                              Re: B+ Voltage rail; Lenovo Y510p VIQY1 NM-A032

                              1: PQ305 pin 2 and 5 (the same): 0V; resistance to ground 10,9 kOhms
                              2: PR305 2nd leg: 0V; resistance to ground 57,3 kOhms

                              Comment


                                #35
                                Re: B+ Voltage rail; Lenovo Y510p VIQY1 NM-A032

                                Have you replaced BQ24737 so far?? Yes it could be faulty but there can be so many reasons. Is PQ310 not broken??PACIN is missing and this is needed to trigger voltage divider for PQ301 gate. When PQ305B,pin5 will be high, GND will reach pin3 and then PR302/304 will work as voltage divider. Since GND is missing on PR304,pin2 its not working as voltage divider. So search all traces related to PACIN and check them. BQ24737,ACOK aka ACPRN will be active low. Do you get 19V on pin20 and 6V on pin16 of PU301??

                                Comment


                                  #36
                                  Re: B+ Voltage rail; Lenovo Y510p VIQY1 NM-A032

                                  Originally posted by SMDFlea View Post
                                  Shouldnt PQ303 be bringing the PQ301 gate voltage down and to do that PQ304 should be switched on.The PQ301 gate voltage should be at least 5V lower ?


                                  Originally posted by mcplslg123 View Post
                                  Have you replaced BQ24737 so far?? Yes it could be faulty but there can be so many reasons. Is PQ310 not broken??PACIN is missing and this is needed to trigger voltage divider for PQ301 gate. When PQ305B,pin5 will be high, GND will reach pin3 and then PR302/304 will work as voltage divider. Since GND is missing on PR304,pin2 its not working as voltage divider. So search all traces related to PACIN and check them. BQ24737,ACOK aka ACPRN will be active low. Do you get 19V on pin20 and 6V on pin16 of PU301??
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                                  Comment


                                    #37
                                    Re: B+ Voltage rail; Lenovo Y510p VIQY1 NM-A032

                                    Originally posted by mcplslg123 View Post
                                    Have you replaced BQ24737 so far?? Yes it could be faulty
                                    No, not yet. I could order it new, and try to replace it, but I would like to learn, how to know if its broken:-)

                                    Is PQ310 not broken??
                                    PQ310 Voltages:
                                    pins 1-3: 0,8V (its the same voltage as PQ302 output)
                                    pin 4: 3,5V
                                    pins 5-8: 1,2V
                                    No shorts

                                    Do you get 19V on pin20 and 6V on pin16 of PU301??
                                    PU301 pin 20: 19,5V
                                    PU301 pin 16: 6V
                                    So yes, those are the voltages present.

                                    Comment


                                      #38
                                      Re: B+ Voltage rail; Lenovo Y510p VIQY1 NM-A032

                                      PR305, pin #1 was requested.

                                      Comment


                                        #39
                                        Re: B+ Voltage rail; Lenovo Y510p VIQY1 NM-A032

                                        Originally posted by mon2 View Post
                                        PR305, pin #1 was requested.
                                        2: PR305 2nd leg: 0V; resistance to ground 57,3 kOhms
                                        1st leg is the same as PQ305 pin 2 and 5.

                                        Or i changed them up, so 1 is 2 and 2 is 1 sorry

                                        Comment


                                          #40
                                          Re: B+ Voltage rail; Lenovo Y510p VIQY1 NM-A032

                                          Originally posted by mcplslg123 View Post
                                          Have you replaced BQ24737 so far?? Yes it could be faulty but there can be so many reasons.
                                          So should I order and replace PU301 (BQ24737), or desolder it and try to measure on the board if its for sure its fault and nothing else?

                                          Comment

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