4 Replies Latest reply on Jan 20, 2013 12:07 PM by Fred

    DQ77MK Power LED problem

    Fred

      Hi,

       

      I'm presently building a new computer. All is working fine, except that I can't make the power LED turn ON when PC is running...

      I've tested the power LED with a 3V battery and it is working. So, my guest would be there's a pin header problem on the motherboard.

       

      Any suggestion to solve this would be appreciate.

       

      Thank you.

        • 1. Re: DQ77MK Power LED problem
          Imanol

          Check if you plugged the header correctly, AFAIK, polarity matters:

           

          x x

          p r

          p r

          -  d

          + d

           

          The + - pair on the bottom left is the power led connector

               where + is where the positive lead of the cable goes (usually marked green)

               where - is where the negative lead of the cable goes (usually marked white)

          p is power switch connector

          r is reset switch connector

          d is hdd led connector

           

          If you plugged it in correctly, try to get a tester from somewhere and check if there's any current at all when the MB is on.

           

          Good luck!

          • 2. Re: DQ77MK Power LED problem
            Fred

            Hi,

             

            I did the test, I'm getting a steady 0.09V at all times when the motherboard is on.

             

            Thanks for your help.

            • 3. Re: DQ77MK Power LED problem
              Imanol

              I'm afraid I made a mistake, the layout I gave to you is incorrect (I didn't check the manual properly), please test it again:

               

              1 2

              3 4

              5 6

              7 8

              9 x

               

              1 is positive lead of HDD LED

              3 is negative lead of HDD LED

              5 and 7 are reset switch pins

              9 is 5V reserved

              6 and 8 are power switch pins

               

              now, for single colored leds (which means that the LED can only be on with a solid color or off)

                   2 is positive lead of HDD LED

                   4 is negative lead of HDD LED

              for dual colored leds (which means the led can be on with colorA or color B dependending if the computer is sleeping (S3 state), or off)

                   same pins, just reverse polarization.

               

              Sorry for the inconvenience!

              • 4. Re: DQ77MK Power LED problem
                Fred

                Hi,

                 

                this schema is the same as your first one (reverse side). The result I had was from the good pins (2 and 4).

                 

                All other pins are well connected and have been tested (HDD LED, Power switch and Reset switch). So, my problem is not coming from pins mismatch connections.

                 

                Also, my case is having a single color led. I've tested reverse polarization and it didn't work.

                 

                Thank you.