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1660 super repair - not detected

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    1660 super repair - not detected

    Hi,

    I have an unknown 1660 super that is not detected

    I have done some measurements of the main inductors

    1 10ohm and 1v
    2 350ohm and 1.8v
    3 30ohm 1.3v
    4 0.07ohm 0.73v
    5 0.07ohm 0.73v
    6 0.07ohm 0.73v
    7 420ohm 5v
    8 500ohm 12v
    9 430ohm 12v

    I have removed the bios IC and tried a few different bios from Dell and HP for example but no different

    Any advice where to go next would be appreciated

    Thanks
    Attached Files

    #2
    Re: 1660 super repair - not detected

    Hi,

    I'm just a noob but 4,5,6 looks like dead short, the voltage is also odd. I would take off the radiator and look at the fets.

    Comment


      #3
      Re: 1660 super repair - not detected

      It looks like two DDR5 chips are desoldered. Usually there are 8 of them. The card can't work w/o them, however I'm not sure if it schould be detected despite that. The low resistance and voltage on 4, 5, 6 looks normal. GPUs main power input has resistances about even 0.13 Ohm. Check if you have the 3,3V somewhere, eg. on the pin 8 of the bios chip.

      Comment


        #4
        Re: 1660 super repair - not detected

        It's .07 not .7. chips may be factory disabled, check GPU numbers most probably ends in A1.

        Comment


          #5
          Re: 1660 super repair - not detected

          I think I had 3.3v somewhere, I will check again, it's a 6gb card so only 6 1gb chips.

          I have checked the pcie reset and that is going high which suggests that is ok

          I have one of them cheap oscilloscopes and looks like the bios is not being probed by the card, tried to get a reading from the crystal it is reading 1.8v but not getting a frequency reading. Not sure if it's the cheap scope, the mothod or the crystal not working.

          Originally posted by DynaxSC View Post
          It looks like two DDR5 chips are desoldered. Usually there are 8 of them. The card can't work w/o them, however I'm not sure if it schould be detected despite that. The low resistance and voltage on 4, 5, 6 looks normal. GPUs main power input has resistances about even 0.13 Ohm. Check if you have the 3,3V somewhere, eg. on the pin 8 of the bios chip.

          Comment


            #6
            Re: 1660 super repair - not detected

            Bios is being probed at boot, I missed it. Still not detected

            Comment


              #7
              Re: 1660 super repair - not detected

              1 10ohm and 1v - PEX supply, this is normal (0.9-1.0V)
              2 350ohm and 1.8v (normal)
              3 30ohm 1.3v (VRAM, normal around 1.3V)
              4 0.07ohm 0.73v (Vcore usually around 0.8V but close enough)
              5 0.07ohm 0.73v ditto
              6 0.07ohm 0.73v ditto
              7 420ohm 5v normal - used to power logic circuitry such as power on sequence logic
              8 500ohm 12v normal
              9 430ohm 12v normal

              @hummel - 0.7 ohms is very normal for a modern GPU or even less - it isn't a short

              @scotchmist - I know you subscribe on my YT channel so you saw my GPU repair videos. It sounds like you have checked pretty much all you can. The xtal oscillator is 27MHz so your scope needs to be 50MHz upwards to see it. Also the amplitude is low. It shows up nice on my 100MHz analog Tektronix scope.

              If BIOS is being read (CS active) then the Crysytal must be working so I wouldn't worry about that

              AFAIK the card should still detect with the RAM chips missing



              Did you check the little capacitors on the PCIe lanes?

              Possible you have corrupted BIOS

              Rich
              Follow me on YouTube
              ------------------
              Learn Electronics Repair
              https://www.youtube.com/channel/UCFX...R8UZ2vg/videos

              Comment


                #8
                Re: 1660 super repair - not detected

                Originally posted by dicky96 View Post

                @hummel - 0.7 ohms is very normal for a modern GPU or even less - it isn't a short
                Is it only me seeing 0.07 not 0.7? Or 0.07 is still ok?

                Comment


                  #9
                  Re: 1660 super repair - not detected

                  @hummel
                  He says he is reading 0.73V on that voltage rail so it strongly suggests there is no short

                  Possibly his meter is not reading low resistances very well, or he is in diode/continuitly mode when, depending on the multimeter, low resistances can look like a dead short 0.000
                  Follow me on YouTube
                  ------------------
                  Learn Electronics Repair
                  https://www.youtube.com/channel/UCFX...R8UZ2vg/videos

                  Comment


                    #10
                    Re: 1660 super repair - not detected

                    Originally posted by dicky96 View Post
                    @hummel
                    He says he is reading 0.73V on that voltage rail so it strongly suggests there is no short

                    Possibly his meter is not reading low resistances very well, or he is in diode/continuitly mode when, depending on the multimeter, low resistances can look like a dead short 0.000
                    Got it now , thanks for the explanation

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