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a1990 820-01326 no wifi/bt

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    a1990 820-01326 no wifi/bt

    hi guys! please help me! motherboard with shorted wifi, replaced from donor board + 2 eeprom...no luck...any idea?





    WLAN_PWR_EN
    PP3v3_g3s_wlan
    pp1v8_g3s_wlanbt_vdd

    all present
    Last edited by phantomEVO; 11-17-2022, 05:25 AM.

    #2
    Re: a1990 820-01326 no wifi/bt

    no one?!

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      #3
      Re: a1990 820-01326 no wifi/bt

      Hello, I guess there is not enought details and your pictures have too low res, we can't see anything.
      I know new chip must have at least same wifi version than original, not under (for security) else bios block the working.

      Comment


        #4
        Re: a1990 820-01326 no wifi/bt

        you are right: here it is!

        what do you mean with "wifi version?"




        Comment


          #5
          Re: a1990 820-01326 no wifi/bt

          I don’t saw it’s apple laptop. I don’t know these laptops.
          In pc world, the wifi version is writed in bios chip. If you replace a wifi chip v4.1 by v4, the bios block. But version 4.2, 5, 6, ok.
          So check if the chip is really the same : same version wifi.

          Comment


            #6
            Re: a1990 820-01326 no wifi/bt

            This is a MacBook Pro…

            Comment


              #7
              Re: a1990 820-01326 no wifi/bt

              please help

              Comment


                #8
                Re: a1990 820-01326 no wifi/bt

                Comment


                  #9
                  Re: a1990 820-01326 no wifi/bt

                  Personally do not have experience with this area but let us give it a stab.

                  The wifi / BT module will often be a stand alone unit that communicates with its master over UART or some similar interface (SPI / I2C / SMBUS). It appears this module uses UART mode with CMOS voltage levels (ie. NOT RS232).

                  In the schematic there are some multiplexers (MUX) devices shown @ U3640 and U3650. These devices must be enabled with the OE# signal. This is an active LOW signal.

                  If the pin #8 of each mux is LOW (0 volts), only then will the signals pass through the WIFI / BT module to the PCH (master).

                  Can you confirm the voltage to ground of the BTUARTMUX_OE_L signal ?

                  The MUXs have to enable so that the module can be configured & data can flow to / from the WIFI module to the host.
                  Attached Files

                  Comment


                    #10
                    Re: a1990 820-01326 no wifi/bt

                    WiFi goes through PCIe, other busses are way too slow.
                    OpenBoardView — https://github.com/OpenBoardView/OpenBoardView

                    Comment


                      #11
                      Re: a1990 820-01326 no wifi/bt

                      Well noted.

                      Confirm that each of the PCIe series caps are present onboard and that they are not defective. A defective / missing cap can halt the enumeration of the PCIe WIFI / BT module.
                      Attached Files

                      Comment

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