Microsoft surface laptop 4 1951 turns on for 10s. Missing 1P8VSB_EN

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • sofles
    Member
    • Jan 2019
    • 17
    • POland

    #1

    Microsoft surface laptop 4 1951 turns on for 10s. Missing 1P8VSB_EN

    Hello

    I have Microsoft surface laptop 4, model number 1951. I bought it broken and I'm trying to fix it for myself.

    Long story short, I bought it as dead. No voltage on battery, not turning on. I replaced battery and PD controller TPS65993AD and now Surface charges battery and turns on.
    The problem is that it shows microsoft logo for 10s and then turns off.

    I checked power rails and I'm missing 1P8VSB_EN power rail, it is not turning on because it has missing SLP_SUS

    And there is my question, is that more likely related to hardware issue or BIOS? I tried to clear BIOS but I have got only CH341 programmer and I have error during programming BIOS and I'm not sure if this programmer supports Winbond 25R256 ICs?

    Thanks for any help
  • mon2
    Badcaps Legend
    • Dec 2019
    • 14020
    • Canada

    #2
    What is the voltage to ground of VSUS_ON? Voltage to ground of EC_RST#?

    Click image for larger version

Name:	vsus_on.png
Views:	187
Size:	98.5 KB
ID:	3461831

    Comment

    • sofles
      Member
      • Jan 2019
      • 17
      • POland

      #3
      Thanks for answer
      VSUS_ON has 1.8V
      I could not find EC_RST# in schemes qand I'm not sure where to measure

      I found reset signals like
      DEVICE_RST# has 3V
      SAM_RESET# has 1.8V

      Comment

      • sofles
        Member
        • Jan 2019
        • 17
        • POland

        #4
        I have completely deslodered BIOS IC and try to run surface to check what will happen and no change, it still shows microsoft surface logo for 10s and shuts down. That makes me wonder is there possibility that SLP_SUS may be programmed in BIOS?

        SUSACK# and SUSWARN# have same voltage 1.67V
        RSMRST# before pressing power button has 0.4V and after pressing PB goes to 0V

        Comment

        • sofles
          Member
          • Jan 2019
          • 17
          • POland

          #5
          Little update. I bought EZP2023+ with 1.8V adapter to program BIOS IC and same thing. It looks like I can't fully erase BIOS IC, when I erase IC and then read its content it still has some data. When I write to IC I get error on verification. I'm not sure what is happening

          Comment

          • mon2
            Badcaps Legend
            • Dec 2019
            • 14020
            • Canada

            #6
            Is the target flash chip removed off the logic board or using the large clamps? Suggest to remove the flash chip off the board so the IC is isolated from other circuits.

            Does this programming tool support exactly this target flash IC part number?

            Comment

            • sofles
              Member
              • Jan 2019
              • 17
              • POland

              #7
              Originally posted by mon2
              Is the target flash chip removed off the logic board or using the large clamps? Suggest to remove the flash chip off the board so the IC is isolated from other circuits.

              Does this programming tool support exactly this target flash IC part number?
              Yes it is removed from MB.

              BIOS IC is Winbond 25R256 but it is auto detected in programmer as 25Q256FW 1.8V. Programmer software doesn't have 25R256 in database, I could add one but I'm not sure all parameters.
              With 25Q256FW selected I can read whole IC, if I want to erase it most of IC is FF but there is still data left, I can write bin file but it gives me an error while veryfiying
              Attached Files

              Comment

              • mon2
                Badcaps Legend
                • Dec 2019
                • 14020
                • Canada

                #8
                Interesting reading:

                ezp2023 doesn't erase all of chip - Badcaps

                Comment

                • sofles
                  Member
                  • Jan 2019
                  • 17
                  • POland

                  #9
                  Originally posted by mon2
                  Thank you for help, I read this but no change. I used now CH341A as they said that it is more realiable but after erasing IC I still have data on it (attachment 1), I cant program anything with CHA341 as it freezes on programming IC. When I thry to program with ezp I get error on 1h (attachment 2)
                  Attached Files

                  Comment

                  • mon2
                    Badcaps Legend
                    • Dec 2019
                    • 14020
                    • Canada

                    #10
                    Change the speed setting to the slowest speed and then attempt the full chip erase again.

                    Comment

                    • sofles
                      Member
                      • Jan 2019
                      • 17
                      • POland

                      #11
                      Originally posted by mon2
                      Change the speed setting to the slowest speed and then attempt the full chip erase again.
                      Same thing, it took almost an hour to erase and write IC but as soon as it gets to veryfying it shows error 1h

                      Comment

                      Related Topics

                      Collapse

                      Working...