I need troubleshooting assistance with provided schematic

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  • Agent24
    I see dead caps
    • Oct 2007
    • 4913
    • New Zealand

    #21
    Re: I need troubleshooting assistance with provided schematic

    Originally posted by atsio
    EC controller (here called LPC) is U4 - W83627EHF
    Oops! It is? Datasheet for that chip says nothing about EC, just super I/O controller.
    Now I realise this is a desktop board - posted in the laptop section - do desktop boards even have an EC? I don't think they need one?
    "Tantalum for the brave, Solid Aluminium for the wise, Wet Electrolytic for the adventurous"
    -David VanHorn

    Comment

    • atsio
      Badcaps Veteran
      • Oct 2013
      • 819
      • Greece

      #22
      Re: I need troubleshooting assistance with provided schematic

      From ISL6566 datasheet:

      " VID4, VID3, VID2, VID1, VID0, and VID12.5
      These are the inputs for the internal DAC that provides the
      reference voltage for output regulation. These pins respond to
      TTL logic thresholds. The ISL6566 decodes the VID inputs to
      establish the output voltage; see VID Tables for
      correspondence between DAC codes and output voltage
      settings. These pins are internally pulled high, to
      approximately 1.2V, by 40ΞA (typically) internal current
      sources; the internal pull-up current decreases to 0 as the VID
      voltage approaches the internal pull-up voltage. All VID pins
      are compatible with external pull-up voltages not exceeding
      the IC's bias voltage (VCC)"

      So replace U1 again

      Comment

      • rookieme
        Badcaps Veteran
        • Oct 2014
        • 396
        • Greece

        #23
        Re: I need troubleshooting assistance with provided schematic

        Thank you again, I'll keep you informed as soon as I replaced it again.

        Comment

        • rookieme
          Badcaps Veteran
          • Oct 2014
          • 396
          • Greece

          #24
          Re: I need troubleshooting assistance with provided schematic

          I swapped the U1 from the working board with no luck [low voltage again].
          The other board works fine with the U1 from the non working one.
          As I can see U1 works ok but the voltage is regulated according the VID0-4 pins.
          I get the correct voltage for the VID signals I get.
          So it is the VID signals that set the voltage.
          U4 could be the resposible for the VID signals?
          Attached Files
          Last edited by rookieme; 06-29-2015, 04:34 AM.

          Comment

          • Agent24
            I see dead caps
            • Oct 2007
            • 4913
            • New Zealand

            #25
            Re: I need troubleshooting assistance with provided schematic

            Originally posted by rookieme
            U4 could be the resposible for the VID signals?
            Could be, or it's doing something to change them incorrectly. I don't know exactly how the circuit works. The datasheet I found doesn't say anything about how the VID pins work except it can read and write to them - so I guess it's maybe possible that it can change them, and override what the CPU says.

            atsio said U4 was the only other place the VID signals went, so if U1 is OK then I agree it makes sense to look at U4 next.
            Attached Files
            Last edited by Agent24; 06-29-2015, 04:11 PM.
            "Tantalum for the brave, Solid Aluminium for the wise, Wet Electrolytic for the adventurous"
            -David VanHorn

            Comment

            • rookieme
              Badcaps Veteran
              • Oct 2014
              • 396
              • Greece

              #26
              Re: I need troubleshooting assistance with provided schematic

              I swapped U4 and the working one continues to work.
              The faulty one continues the problem with cpu undervoltage.
              So what tells U4 what signals to produce?

              Comment

              • atsio
                Badcaps Veteran
                • Oct 2013
                • 819
                • Greece

                #27
                Re: I need troubleshooting assistance with provided schematic

                Originally posted by atsio
                If i were you I would replace and Q16,Q17 and Q18
                And consider and the other 8 fets on the other two phases

                Comment

                • ktmmotocross
                  Boardkiller
                  • Feb 2014
                  • 3553
                  • slovakia

                  #28
                  Re: I need troubleshooting assistance with provided schematic

                  reflow cpu socket.

                  Comment

                  • rookieme
                    Badcaps Veteran
                    • Oct 2014
                    • 396
                    • Greece

                    #29
                    Re: I need troubleshooting assistance with provided schematic

                    Well, new info for the issue.
                    At the working one, if I remove the bios [removable] I get the same "fault".
                    So I presume that the low voltage is regular operation [like safe mode], set by cpu if something else doesn't work as it should.
                    So I have a fault somewhere that prevents the normal operation of the cpu and then cpu signals for low core voltage - that makes some sense.
                    All I have now to find the fault, many components to try but will start from the basic ones [NB, SB]
                    I'll keep cpu socket reflow for the end....

                    Comment

                    • ktmmotocross
                      Boardkiller
                      • Feb 2014
                      • 3553
                      • slovakia

                      #30
                      Re: I need troubleshooting assistance with provided schematic

                      id signals comes from cpu through socket. have one dv6000 with low voltage. after reflow socket it work ok

                      Comment

                      • Agent24
                        I see dead caps
                        • Oct 2007
                        • 4913
                        • New Zealand

                        #31
                        Re: I need troubleshooting assistance with provided schematic

                        Dumb question I know, but I suppose you already checked for corrupt BIOS then?
                        "Tantalum for the brave, Solid Aluminium for the wise, Wet Electrolytic for the adventurous"
                        -David VanHorn

                        Comment

                        • rookieme
                          Badcaps Veteran
                          • Oct 2014
                          • 396
                          • Greece

                          #32
                          Re: I need troubleshooting assistance with provided schematic

                          Originally posted by Agent24
                          Dumb question I know, but I suppose you already checked for corrupt BIOS then?
                          Not dump at all, from the working one if I remove the bios I get the same failure. Yes I did made a swap as they are removable.
                          The fault has been found finally as it worked after reballing the NB.
                          As I mentioned the low core voltage was the result of an other issue.
                          Thank you all for your time and effort.

                          Comment

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