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Dell 1525 DS2 Intel Tps51120 faulty or not?

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    #21
    Re: Dell 1525 DS2 Intel Tps51120 faulty or not?

    Sorry sir I'm lost. Page 37 of the schem is keyboard connector there are no R235, R236 and Q19 there. I think you mean page 39, MAX8731 chager IC. Or maybe I'm on a different schem?

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      #22
      Re: Dell 1525 DS2 Intel Tps51120 faulty or not?

      Sheet 37 upper right corner of the charger ic.

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        #23
        Re: Dell 1525 DS2 Intel Tps51120 faulty or not?

        This are the images of page 37 and page 39 which contain charger ic.
        Attached Files

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          #24
          Re: Dell 1525 DS2 Intel Tps51120 faulty or not?

          Yes you are right, it's page 39. I was referring to the AMD version of the schematic in page 37. Sorry about that.

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            #25
            Re: Dell 1525 DS2 Intel Tps51120 faulty or not?

            Finally got a hold of the new IC, It had a one day delay because of unknown reason. I'll let you guys know the results as soon as possible. And I hope it will be a positive one. Thanks again!

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              #26
              Re: Dell 1525 DS2 Intel Tps51120 faulty or not?

              Originally posted by lezsimply View Post
              So far these are voltages I measured on U46 MAX8731AE Battery IC

              pin 22 DCIN 19.48v
              pin 2 ACIN 2.24v
              pin 11 VDD 3.3v
              pin 26 VCC 5.34v
              pin 13 ACOK (ACAV_IN) 3.26v
              pin 21 LDO 5.37v

              R40 to ad+ 19.48v while opposite gives 2.24v to C383 which goes to acin max8713ae
              This resistor R40 is a 365kohm but meter says 57k only (Page 39)
              Hello got the exact same readings at MAX8731A on a non post Dell studio 1555 page 46 on schematic. At first I thought to reflow ATO GPU due to bad overheating because of clogged fan and vents.

              Also I stumbled upon weird ACOK reading and was confused.
              From specs it should be:
              ACOK Sink Current VACOK = 0.4V, ACIN = 1.5V
              ACOK Leakage Current VACOK = 5.5V, ACIN = 2.5V
              Mine is reading VACOK = 3.3V, ACIN = 2.4V with AC adapter connected like yours.

              So did you replace the MAX8731 IC ?? Please give an update!
              Attached Files

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                #27
                Re: Dell 1525 DS2 Intel Tps51120 faulty or not?

                Never mind! These reading are the correct ones for this chip. I managed to fix the no screen - no boot issue simply by reflowing with insat flux the GPU in that case an ATI 4570!!
                Everything is working nicely now!! Thanks for the info!

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                  #28
                  Re: Dell 1525 DS2 Intel Tps51120 faulty or not?

                  I forgot to post my results here. Sorry for that I had a motorcycle accident after christmas and needed to take the doctor's advice to rest.

                  I have not yet succeeded in repairing this laptop. I manage to replace the max IC but still same effect no power. All readings are same and dunno where to go from there. Problem might be somewhere else. Anyone got more ideas. Thanks again!

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                    #29
                    Re: Dell 1525 DS2 Intel Tps51120 faulty or not?

                    Did you reflash bios? EC oscillator 32KHz working? Pin 15 of EC still 0V?
                    Then change the EC. Look for damage on EC - like the picture:
                    Attached Files

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                      #30
                      Re: Dell 1525 DS2 Intel Tps51120 faulty or not?

                      No visible damage on EC. Replaced oscillator X5 with working one. Problem is, even if I replace EC and bios I would still not get ACIN voltage. If I got ACIN high then EC would work? thanks

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                        #31
                        Re: Dell 1525 DS2 Intel Tps51120 faulty or not?

                        Which ACIN voltage do you refer to? EC gets its power from 3d3V_aux_s5 rail, which you said you have (supplied by TPS51120 VREG3)

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                          #32
                          Re: Dell 1525 DS2 Intel Tps51120 faulty or not?

                          Pin no.93 of U22 (WPC8763) AC_IN. That is what I understood in previous post.

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                            #33
                            Re: Dell 1525 DS2 Intel Tps51120 faulty or not?

                            AC_IN# - it an active low signal (#)- meaning it is low when AC is plugged in.
                            It is connected to ground through the Q23 which is switched by acav_in signal.
                            When adapter is not connected, then MAX8731 is not working, so no LDO output to
                            switch Q23 to ground, so AC_IN# is high.

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                              #34
                              Re: Dell 1525 DS2 Intel Tps51120 faulty or not?

                              Ok thanks. Now I'm more confused. Meaning, having 0v on AC_IN# is normal? So that's why there is no effect even if I replaced charger IC. Every voltage output on max is ok I suppose.

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                                #35
                                Re: Dell 1525 DS2 Intel Tps51120 faulty or not?

                                That is my understanding. If you have a charged battery - then plug it in and look if AC_IN# signal turns high.

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                                  #36
                                  Re: Dell 1525 DS2 Intel Tps51120 faulty or not?

                                  I just remembered the battery is dead. I'll try to borrow from friends if they have one identical to this one.

                                  All pins related to vcc and avcc have 3.30v present (pins 19,46,76,88,102 and 115) of U22 SIO.

                                  I would also like to know if there is a way to bypass power button like shorting some pins?

                                  Thanks very much for your help

                                  Comment


                                    #37
                                    Re: Dell 1525 DS2 Intel Tps51120 faulty or not?

                                    Bypass power button:

                                    1. Short the capacitor EC3 to ground, or
                                    2. Short pin 3 of CN2 to ground

                                    Comment


                                      #38
                                      Re: Dell 1525 DS2 Intel Tps51120 faulty or not?

                                      Shorting ec3 or pin 3 to ground shows no result. Do you guys have datasheet for this chip WPC8763LDG or wpc8763la0dg. cannot seem to find the correct one. Thanks!

                                      Comment


                                        #39
                                        Re: Dell 1525 DS2 Intel Tps51120 faulty or not?

                                        I think it is not available. What do you need it for?

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                                          #40
                                          Re: Dell 1525 DS2 Intel Tps51120 faulty or not?

                                          I want to see the pinouts because I wan't to substitute other version. There is no available in the market with same model. All I see is wpc8768 and wpc8769. Would this fit or most likely similar? Thanks

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