DA0U92MB6D0 REV:D NO POWER

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  • NConstantinou
    Badcaps Veteran
    • May 2017
    • 348
    • Cyprus
    #1

    DA0U92MB6D0 REV:D NO POWER

    Dear all,

    i have the above board and on PQ21(M3016D) i have input but no output. Therefore i have no input on PR7.
    i do not have similar transistor to substitute. how can i overcome this!
    Thanks
    Tags: None
    • mon2
      Badcaps Legend
      • Dec 2019
      • 14659
      • Canada
      #2
      Remove all power. Meter in resistance mode. Measure the resistance to ground on pin #3 = PR7 = main power rail. What is the exact resistance? If it is too low, there is a fault on the main power rail.

      Connect the power adapter. Measure the voltage to ground on the gate pin # 1 on PQ21. Checking the gate voltage for this mosfet which should be higher than the voltage being passed between source / drain pins to fully enable. Gate pin should be ~25v to enable.

      If not, confirm the voltage to ground of REGN pin # 16 which should be ~6v.

        Comment

        • NConstantinou
          Badcaps Veteran
          • May 2017
          • 348
          • Cyprus
          #3
          The resistance of PR7 to ground is 45 OHMS. Pin 1 of PQ21 has 19v. the gate of PQ21 has 0v.
          i do not get any voltage on REGN pin # 16. i replace the ic with BQ25A from another USED board board but i do not know if it is good.
          is anything i can do to test the ic!
          By checking the coils i found that the 3.3v coil has also 45 Ohms resistance
          Thanks
          Last edited by NConstantinou; 09-09-2025, 10:02 AM.

            Comment

            • mon2
              Badcaps Legend
              • Dec 2019
              • 14659
              • Canada
              #4
              PR7 to ground is 45 OHMS
              Yes, something is wrong with the main power rail.

              With no power to the board, measure the resistance from PR7 to the 3v3 coil where you measured 45R ohms to ground. What is the resistance?

                Comment

                • NConstantinou
                  Badcaps Veteran
                  • May 2017
                  • 348
                  • Cyprus
                  #5
                  The resistance I measured was on PR7 45 ohms
                  Before I have changed pq34 which was short and then I focus on ic charger as my first step.

                  at this moment I went back to check pa34 again and I found it short again.
                  I changed it and now the resistance on PR7 is .5 which is normal, but 0v on PR7 which means problem with charger ic.

                    Comment

                    • mon2
                      Badcaps Legend
                      • Dec 2019
                      • 14659
                      • Canada
                      #6
                      What is the resistance to ground of PR7?

                        Comment

                        • NConstantinou
                          Badcaps Veteran
                          • May 2017
                          • 348
                          • Cyprus
                          #7
                          Thr resistance on PR7 now is 43K

                            Comment

                            • NConstantinou
                              Badcaps Veteran
                              • May 2017
                              • 348
                              • Cyprus
                              #8
                              Doing more testing i found on PU 2 ic pin #4 is connected with 2 100k resistors. Those where having wrong value and i change them.
                              After that i got PR7 19V but not 3.3 and 5v.
                              time for that step now

                                Comment

                                • NConstantinou
                                  Badcaps Veteran
                                  • May 2017
                                  • 348
                                  • Cyprus
                                  #9
                                  PU12. I do have +VIN 19v, pin #3 ref 2v, pin 17 VREG5 1.5v, pin 8 VREG3 0.09v, pin 13 EN0 2.5v.
                                  what is the order of power sequence of G5608Dr51U 9PU12) ic!

                                  IF +5VPCU WHICH IS MISSING FROM IC COMES FROM PQ7!
                                  ON PQ7 PIN 1 AND 3 I GET 1.5V AND ON PIN 2 12V

                                  Thanks
                                  Last edited by NConstantinou; 09-12-2025, 06:52 AM.

                                    Comment

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