Announcement

Collapse
No announcement yet.

Acer Aspire 5750 no B+ voltage

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    #21
    Re: Acer Aspire 5750 no B+ voltage

    correct values
    Attached Files

    Comment


      #22
      Re: Acer Aspire 5750 no B+ voltage

      Originally posted by multiplexer View Post
      correct values
      my measurements as follow
      Attached Files

      Comment


        #23
        Re: Acer Aspire 5750 no B+ voltage

        Originally posted by multiplexer View Post
        correct values
        Better to put this way
        Attached Files

        Comment


          #24
          Re: Acer Aspire 5750 no B+ voltage

          pq17 must be shorted or acoff is on.

          have one of these with bad pq17

          Comment


            #25
            Re: Acer Aspire 5750 no B+ voltage

            Possible faults:
            ACOFF incorrect value
            PQ17 short between the collector and emitter
            PQ14 short between pins 1-2 and 4-5
            Attached Files

            Comment


              #26
              Re: Acer Aspire 5750 no B+ voltage

              No shorts on PQ17 or PQ14. there is only one option left i think and it is ACOFF . I assume ACOFF comes from KBC so do you advice to change it or there is a way to test it.

              PS. if shorted pin 1 and 8 of PQ7 the system works without battery fine if i insert battery and short the pins of PQ7 short occures on Power supply.

              i have not tested with the battery beause battery is empty and i dont have other one

              Comment


                #27
                Re: Acer Aspire 5750 no B+ voltage

                Measure the voltage on ACOFF PQ17
                Desolders PQ17 if your laptop is running (no short on 1-8 FP7) program bios U36, U38

                Comment


                  #28
                  Re: Acer Aspire 5750 no B+ voltage

                  Originally posted by multiplexer View Post
                  Measure the voltage on ACOFF PQ17
                  Desolders PQ17 if your laptop is running (no short on 1-8 FP7) program bios U36, U38
                  ACOFF is 0v
                  removed PQ17 but no start
                  now flashing U36 and U38 then write the result here

                  flashed both kbc and main but the result is same.
                  there is one odd situation when i turn on the power the output of PQ7 rises slowly upto 0.8v and when i turn off the power the output drops down slowly to 0v. i took a video and share the youtube link soon.
                  Last edited by ahmetozay; 09-12-2014, 03:26 AM.

                  Comment


                    #29
                    Re: Acer Aspire 5750 no B+ voltage

                    PR38 fails
                    replace

                    Comment


                      #30
                      Re: Acer Aspire 5750 no B+ voltage

                      Please attach your schema compare if it is equal to my

                      Comment


                        #31
                        Re: Acer Aspire 5750 no B+ voltage

                        Originally posted by multiplexer View Post
                        Please attach your schema compare if it is equal to my
                        here it is
                        Attached Files

                        Comment


                          #32
                          Re: Acer Aspire 5750 no B+ voltage

                          Here is the youtube link http://youtu.be/B78hyYI4xUg

                          Comment


                            #33
                            Re: Acer Aspire 5750 no B+ voltage

                            Originally posted by multiplexer View Post
                            PR38 fails
                            replace
                            removed PR38 and measured 47k as stated in the schema so PR38 is ok

                            Comment


                              #34
                              Re: Acer Aspire 5750 no B+ voltage

                              My schematic is rev 0.1
                              I confirm check PR38 = 47K ohm
                              Thanks for the schematic

                              Comment


                                #35
                                Re: Acer Aspire 5750 no B+ voltage

                                Originally posted by multiplexer View Post
                                My schematic is rev 0.1
                                I confirm check PR38 = 47K ohm
                                Thanks for the schematic
                                PR38 is ok 47K ohm measured

                                Comment


                                  #36
                                  Re: Acer Aspire 5750 no B+ voltage

                                  Originally posted by ahmetozay View Post
                                  Thanks for the reply

                                  PQ14
                                  1=0v
                                  2=0v
                                  3=0v
                                  4=0v
                                  5=0v
                                  6=6.1v
                                  Measure the voltages on all the pins of Q8, Q10, Q14
                                  If you confirm these measures failure PQ14. Replace it

                                  Comment


                                    #37
                                    Re: Acer Aspire 5750 no B+ voltage

                                    Have you checked PQ6?
                                    checked the drain and source short.

                                    Comment


                                      #38
                                      Re: Acer Aspire 5750 no B+ voltage

                                      looks like ocp problem, Replace with the correct mosfet 4459, to be sure, remove PR14 and mesure again if you find 19V on PQ7 drain, please replace with the same reference;

                                      Comment


                                        #39
                                        Re: Acer Aspire 5750 no B+ voltage

                                        Checked PQ6 if it is short then 19v will comes to PQ7 gate and this FET will be closed and no output voltage to onward circuit so checked and repalced PQ6.

                                        Comment


                                          #40
                                          Re: Acer Aspire 5750 no B+ voltage

                                          Originally posted by smali View Post
                                          Checked PQ6 if it is short then 19v will comes to PQ7 gate and this FET will be closed and no output voltage to onward circuit so checked and repalced PQ6.
                                          well already checked and replaced nothing wrong there.i am stuck really.
                                          if i short pin 8 of PQ6 with pin of PQ7 system works without battery. the only reason is there is 0.25 v on the gate pins of PQ6 and PQ7.

                                          Comment

                                          Working...
                                          X