La-c881p

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • riki_22
    Senior Member
    • Jun 2014
    • 63
    • italia

    #21
    Re: La-c881p

    Originally posted by mon2
    Remove battery. Connect adapter.

    1) voltage on pin 6 (acdet; pu300) ?
    2) voltage on pin 17 (pu300) ?
    3) voltage on pin 1, pl300? Pin 2, pl300?
    4) pl301, pin 1? Pin 2?
    5) confirm the nearby diodes are ok (power removed, meter in diode mode). Should conduct in one direction, block in the other).
    6) pin 15 voltage of pu300 with adapter only?
    Pu300 with Adapter
    P6 3.2v
    P17 0v
    P15 1.72v

    Pl301 p1 3.12 and P2 3.12
    Pl300 p1 19.6 and P2 19.6

    The diode work ok not shortly
    Last edited by riki_22; 05-24-2021, 07:36 AM.

    Comment

    • riki_22
      Senior Member
      • Jun 2014
      • 63
      • italia

      #22
      Re: La-c881p

      Originally posted by piernov
      Voltage from battery goes through PQ305 & PQ303 body diode to reach VCC pin of charger IC.
      PD300 should be replaced first, not much point troubleshooting further if parts are missing.

      You need a Schottky diode of at least 30V reverse voltage and 30mA forward current and the same package. So yes RB501V-40 should be good instead of SDMK0340L

      Note that it's possible there is a secondary problem and PD300 will burn again, so keep a few aside in case. It's also possible it's the only problem and replacing it will solve it.

      Hi i Just try the RB501-V40 but mainboard not Power with Adapter what measurements can i take to find the problem?
      rb501-v40 for me is not good because it does not turn on even with the battery alone
      Last edited by riki_22; 05-24-2021, 07:01 AM.

      Comment

      • mon2
        Badcaps Legend
        • Dec 2019
        • 13897
        • Canada

        #23
        Re: La-c881p

        You have a fault at pr300, current sense resistor. Review the voltage before and after this component. It must be very close to the adapter in voltage. This part may need to be replaced.

        Consider to carefully remove pr303 and pr304 then check the voltage through the current sense resistor again. Does the voltage reading match the adapter voltage? If not, pr300 is damaged.

        See and review attached partial schematic.

        @ 1 - voltage must match the adapter DCIN value.

        @ 4 - voltage should be very close to the adapter DCIN value. From your post, this voltage @ 4 is 3v12 ?? If yes, then the charger IC is noting a very large voltage drop and shutting this component down. That is, approx 19VIN is dropping to 3v12 which is too much of a load for this switching IC to enable.

        You can remove the above mentioned resistors and then check again @1 and @ 4.

        Also inspect this SMD current sense resistor for damage. Power all down and check the resistance from @1 and @4 points.
        Attached Files
        Last edited by mon2; 05-24-2021, 07:20 AM.

        Comment

        • riki_22
          Senior Member
          • Jun 2014
          • 63
          • italia

          #24
          Re: La-c881p

          Originally posted by mon2
          You have a fault at pr300, current sense resistor. Review the voltage before and after this component. It must be very close to the adapter in voltage. This part may need to be replaced.

          Consider to carefully remove pr303 and pr304 then check the voltage through the current sense resistor again. Does the voltage reading match the adapter voltage? If not, pr300 is damaged.

          See and review attached partial schematic.

          @ 1 - voltage must match the adapter DCIN value.

          @ 4 - voltage should be very close to the adapter DCIN value. From your post, this voltage @ 4 is 3v12 ?? If yes, then the charger IC is noting a very large voltage drop and shutting this component down. That is, approx 19VIN is dropping to 3v12 which is too much of a load for this switching IC to enable.

          You can remove the above mentioned resistors and then check again @1 and @ 4.

          Also inspect this SMD current sense resistor for damage. Power all down and check the resistance from @1 and @4 points.
          i checked the voltage at the end of pr300 and they are the same as the power supply input, i can't find pr303 and pr304 to verify what you say

          Comment

          • Sephir0th
            Badcaps Legend
            • Oct 2020
            • 1262
            • Germany

            #25
            Re: La-c881p

            Right, PR303 and PR304 are Just Pads, No component there. but i don't think the issue is there. Never Heard about a failed Current Resistor.

            I believe we need a complete measurement of PU300 Résistance to GND, and Voltage (Only Battery/Only Adapter/both present) to See what is going on there.

            A complete D-S-G Résistance measurement of PQ305 could be also helpful
            Last edited by Sephir0th; 05-24-2021, 07:35 AM.
            FairRepair on YouTube

            Comment

            • mon2
              Badcaps Legend
              • Dec 2019
              • 13897
              • Canada

              #26
              Re: La-c881p

              Originally posted by riki_22
              i checked the voltage at the end of pr300 and they are the same as the power supply input, i can't find pr303 and pr304 to verify what you say

              Pl300 p1 3.12 and P2 3.12


              Are these readings correct ?

              PL300 (P1) should be the same voltage value AFTER PR300. Confirm it.

              Also, see attached for the resistor locations.
              Attached Files
              Last edited by mon2; 05-24-2021, 07:38 AM.

              Comment

              • riki_22
                Senior Member
                • Jun 2014
                • 63
                • italia

                #27
                Re: La-c881p

                Originally posted by mon2

                Pl300 p1 3.12 and P2 3.12


                Are these readings correct ?

                PL300 (P1) should be the same voltage value AFTER PR300. Confirm it.
                sorry friend
                I had inverted the measurements between pl 300 and pl301.
                with certainty the correct measurements are:
                in pl301 p1 3.2V and p2 3.2V
                in pl300 p1 19.6V and p2 19.6V

                Comment

                • riki_22
                  Senior Member
                  • Jun 2014
                  • 63
                  • italia

                  #28
                  Re: La-c881p

                  Originally posted by Sephir0th
                  Right, PR303 and PR304 are Just Pads, No component there. but i don't think the issue is there. Never Heard about a failed Current Resistor.

                  I believe we need a complete measurement of PU300 Résistance to GND, and Voltage (Only Battery/Only Adapter/both present) to See what is going on there.

                  A complete D-S-G Résistance measurement of PQ305 could be also helpful

                  making all these measurements will take me time, I just wanted to remind you that instead of pd300 I didn't put anything, and I wanted to clarify that I tried to make the bridge and in pd300 it turns on but as soon as I insert the battery the power supply is shorted, so according to me I have to find the right component to install in pd300. i have already tried RB501V-40 but with this it does not turn on.

                  Comment

                  • Sephir0th
                    Badcaps Legend
                    • Oct 2020
                    • 1262
                    • Germany

                    #29
                    Re: La-c881p

                    I know what you mean, but i had a similar Case before and i was able to solve it (tbh with additional Help from here) with this complete measurement. Funny Part: it was Bad Schottky.

                    However you can continue to find the correct replacement for PD300 and May Check the suspected Mosfets again. Also Check all Diodes around the Controller.

                    And If this all will still Not work, then i See No other way than have a much deeper Look Into the Circuit.
                    Last edited by Sephir0th; 05-24-2021, 08:55 AM.
                    FairRepair on YouTube

                    Comment

                    • riki_22
                      Senior Member
                      • Jun 2014
                      • 63
                      • italia

                      #30
                      Re: La-c881p

                      Only adapter

                      PIN1 19,6V
                      PIN2 19,6V
                      PIN3 19,3V
                      PIN4 25V
                      PIN5 3,2V
                      PIN6 2,8V
                      PIN7 0V
                      PIN8 0v
                      PIN9 0v
                      PIN10 0v
                      PIN11 1,5v
                      PIN12 1,5V
                      PIN13 0,18V
                      PIN14 0V
                      PIN15 1,5V
                      PIN16 5,3V
                      PIN17 0V
                      PIN18 3,2V
                      PIN19 3,2V
                      PIN20 3,2V
                      PIN21 5,3V
                      PIN22 0V
                      PIN23 0,35V
                      PIN24 5,3V
                      PIN25 5,8V
                      PIN26 3,6V
                      PIN27 3,2V
                      PIN28 19,6V

                      Only Battery
                      PIN1 7,1V
                      PIN2 7,1V
                      PIN3 0V
                      PIN4 0V
                      PIN5 0V
                      PIN6 0V
                      PIN7 0V
                      PIN8 0,18v
                      PIN9 0,04v
                      PIN10 1v
                      PIN11 2,8v
                      PIN12 2,8v
                      PIN13 0v
                      PIN14 0v
                      PIN15 0v
                      PIN16 5,3v
                      PIN17 7,5v
                      PIN18 0,32v
                      PIN19 7,5v
                      PIN20 7,5v
                      PIN21 5,3v
                      PIN22 0v
                      PIN23 0v
                      PIN24 5,3v
                      PIN25 7,2v
                      PIN26 7,3v
                      PIN27 7,4v
                      PIN28 6,9v


                      what do you think about it?
                      Last edited by piernov; 05-24-2021, 10:32 AM. Reason: double post

                      Comment

                      • Sephir0th
                        Badcaps Legend
                        • Oct 2020
                        • 1262
                        • Germany

                        #31
                        Re: La-c881p

                        1) I'm still Not convinced that PQ303 is fine and i still don't know anything about the condition of PQ305.

                        2) Clock and Data Voltages are a Bit lower when Adapter is present. But can't say this could be an issue. Also the 1.5V at BATPRES# seems a Bit too Low for me.

                        3) REGN measures usually more or less exactly 6V

                        4) Never saw ILIM Voltage above 1.X Volt, but couldn't mean anything.
                        Last edited by Sephir0th; 05-24-2021, 11:44 AM.
                        FairRepair on YouTube

                        Comment

                        • riki_22
                          Senior Member
                          • Jun 2014
                          • 63
                          • italia

                          #32
                          Re: La-c881p

                          Originally posted by Sephir0th
                          1) I'm still Not convinced that PQ303 is fine and i still don't know anything about the condition of PQ305.

                          2) Clock and Data Voltages are a Bit lower when Adapter is present. But can't say this could be an issue. Also the 1.5V at BATPRES# seems a Bit too Low for me.

                          3) REGN measures usually more or less exactly 6V

                          4) Never saw ILIM Voltage above 1.X Volt, but couldn't mean anything.
                          PQ303 with adapter
                          D 19.6V
                          S 3.2V
                          G 3.6V

                          PQ303 with Battery
                          D 7.4V
                          S 7.5V
                          G 7.4V

                          PQ303 battery and adapter
                          D 19.6V
                          S 7.5V
                          G 8V

                          PQ305 Battery and adapter
                          D 7.4V
                          S 7.5V
                          G 0.005V

                          PQ305 with Battery
                          D 7.5V
                          S 7.5V
                          G 0.3V

                          PQ305 with adapter
                          D 2.5V
                          S 3.2V
                          G 3.2V

                          Comment

                          • riki_22
                            Senior Member
                            • Jun 2014
                            • 63
                            • italia

                            #33
                            Re: La-c881p

                            Originally posted by Sephir0th
                            I know what you mean, but i had a similar Case before and i was able to solve it (tbh with additional Help from here) with this complete measurement. Funny Part: it was Bad Schottky.

                            However you can continue to find the correct replacement for PD300 and May Check the suspected Mosfets again. Also Check all Diodes around the Controller.

                            And If this all will still Not work, then i See No other way than have a much deeper Look Into the Circuit.
                            battery+adapter

                            PIN1 19,6V
                            PIN2 19,6V
                            PIN3 19,3V
                            PIN4 25V
                            PIN5 3,2V
                            PIN6 2,8V
                            PIN7 0V
                            PIN8 0v
                            PIN9 0v
                            PIN10 0v
                            PIN11 3,3v
                            PIN12 3,3V
                            PIN13 0,04V
                            PIN14 0V
                            PIN15 0V
                            PIN16 5,3V
                            PIN17 7,8V
                            PIN18 0V
                            PIN19 7,8V
                            PIN20 7,8V
                            PIN21 5,3V
                            PIN22 0V
                            PIN23 0,3V
                            PIN24 5,3V
                            PIN25 8,8V
                            PIN26 8,3V
                            PIN27 6,7V
                            PIN28 19,6V

                            I also made the measurements of pq303 and pq305 and also of pu300 what do you think now?
                            Last edited by riki_22; 05-25-2021, 02:49 AM.

                            Comment

                            • Sephir0th
                              Badcaps Legend
                              • Oct 2020
                              • 1262
                              • Germany

                              #34
                              Re: La-c881p

                              PQ305 is Open when Battery and Adapter is present, which isn't the correct behaviour Afaik.

                              Did you checked PQ305 in Ohms Mode between D-S-G before?

                              Actually my primary suspect is either PQ305 or PU300. to be Bad. But Check internal Résistance of PR320 before.
                              Last edited by Sephir0th; 05-25-2021, 09:21 AM.
                              FairRepair on YouTube

                              Comment

                              • piernov
                                Super Moderator
                                • Jan 2016
                                • 4435
                                • France

                                #35
                                Re: La-c881p

                                Originally posted by Sephir0th
                                PQ305 is Open when Battery and Adapter is present, which isn't the correct behaviour Afaik.
                                No that's expected.
                                OpenBoardView — https://github.com/OpenBoardView/OpenBoardView

                                Comment

                                • riki_22
                                  Senior Member
                                  • Jun 2014
                                  • 63
                                  • italia

                                  #36
                                  Re: La-c881p

                                  Originally posted by Sephir0th
                                  PQ305 is Open when Battery and Adapter is present, which isn't the correct behaviour Afaik.

                                  Did you checked PQ305 in Ohms Mode between D-S-G before?

                                  Actually my primary suspect is either PQ305 or PU300. to be Bad. But Check internal Résistance of PR320 before.
                                  PQ305 in Ohms is OL in D-S-G

                                  PR320 where can i find it?
                                  Last edited by riki_22; 05-25-2021, 10:33 AM.

                                  Comment

                                  • riki_22
                                    Senior Member
                                    • Jun 2014
                                    • 63
                                    • italia

                                    #37
                                    Re: La-c881p

                                    Originally posted by riki_22
                                    PQ305 in Ohms is OL in D-S-G

                                    PR320 where can i find it?

                                    what do you think if i try to replace
                                    - PU300 BQ24777
                                    - PD300 SDMK0340L
                                    - PQ303 SIR472DP
                                    - PQ304 SI7716ADN

                                    Comment

                                    Related Topics

                                    Collapse

                                    • Tynan Dill
                                      Vizio e601i-A3 - Has Sound and Display, But No Backlight - Bad Power Supply Board or Bad LED Bulbs ?
                                      by Tynan Dill
                                      I was given this TV from my great uncle. He said it just wouldn't turn on one day out of nowhere, replaced the TV, and gave it to me to possibly fix and use for myself.

                                      Upon bringing it home and plugging it up, it showed a standby light.

                                      I powered it on and without a flashlight, the display showed the "V" but the lighting is very dim, but visible.

                                      The screen seems to blackout and stay black, but with a flashlight I can see the display.

                                      With my Playstation 4 connected via HDMI, and running a game I can hear sound.

                                      Assuming...
                                      11-22-2024, 01:46 PM
                                    • sam_sam_sam
                                      Desoldering gun station modified to use a 18 volt @ 20 amp switching power supply
                                      by sam_sam_sam
                                      I have wanting to do this project for quite sometime now and I finally found a switching power supply that will work on this desoldering gun station ZD-915 that the original switching power supply took a shit and just was not worth trying to fix it because this switching power is not quite big enough to handle the heater element and the vacuum pump

                                      One note when I tested the switching power supply and the voltage control board I noticed that this desoldering gun heat up much faster than the original switching power supply which I was really surprised by to the point that I might buy...
                                      03-31-2024, 02:12 PM
                                    • hillbillybubba
                                      XPS 13 9360 - Is it possible to directly charge the battery, at the connector, with adjustable power supply?
                                      by hillbillybubba
                                      I see the positive and negative wires on the connector, but will it even allow a charge without the other connectors doing whatever communication it is that they do?

                                      I'm well-versed in battery charging, just not laptop batteries. (I'm a lithium battery reseller)

                                      Laptop became unresponsive while in storage, battery was in great health the last time I cut it off, but now it's reading zero volts at the connector.
                                      01-24-2025, 11:01 AM
                                    • sam_sam_sam
                                      Modification to a ZD-987 desoldering/soldering station using a external switching power supply
                                      by sam_sam_sam
                                      I have been working on this concept for quite some time now with limited success but recently I found a switching power supply that is setup for the voltage that this soldering station needs to operate at however it also needs part of the secondary circuit from the original switching power because you need several voltage rails

                                      I once tried to get a ZD-915 desoldering station to work on a 18 volt battery power supply but unfortunately things did not go well but I did find a work around but I might try this idea again but going at a little differently more about this another time...
                                      07-01-2024, 06:34 AM
                                    • Document Archive
                                      DELL XPS 9350 Notebook 13 Specification for Upgrade or Repair
                                      by Document Archive
                                      This specification for the DELL XPS 9350 Notebook can be useful for upgrading or repairing a laptop that is not working. As a community we are working through our specifications to add valuable data like the 9350 boardview and 9350 schematic. Our users have donated over 1 million documents which are being added to the site. This page will be updated soon with additional information. Alternatively you can request additional help from our users directly on the relevant badcaps forum. Please note that we offer no warranties that any specification, datasheet, or download for DELL XPS 9350 Notebook...
                                      09-06-2024, 07:11 AM
                                    • Loading...
                                    • No more items.
                                    Working...