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    Help: what are these SMD package components?

    trying to bring life back to a tablet. Without a schematic, its a tough slog. Anyway, can some one help me and tell me what these "larger" smd package components are and what the markings means.

    In the picture, they are 1r0 237 sbt, 1r2 237 um5, 1r5 235 vjs. Most seem associated with the powering domain.

    My guess is some form of resistor but they don't seem to measure out correctly as a "plain resistor"

    Thanks for your guidance.
    Attached Files

    #2
    Re: Help: what are these SMD package components?

    They are power inductors, (coils) 1µH and 1.5µH

    Comment


      #3
      Re: Help: what are these SMD package components?

      thanks... do any of those number give some idea of ratings? (ie. amps or otherwise)

      One other question then: if they don't measure some form of low resistance, then that likely means they are burned out, right?
      Last edited by budwich; 09-06-2019, 11:44 AM.

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        #4
        Re: Help: what are these SMD package components?

        Those inductors are for the SMPS, I.E. U2 LT3633: https://www.analog.com/en/products/l...oduct-overview
        You can look up the spec sheet of other ICs then you can start checking Voltages
        Never stop learning
        Basic LCD TV and Monitor troubleshooting guides.
        http://www.badcaps.net/forum/showthr...956#post305956

        Voltage Regulator (LDO) testing:
        http://www.badcaps.net/forum/showthr...999#post300999

        Inverter testing using old CFL:
        http://www.badcaps.net/forum/showthr...er+testing+cfl

        Tear down pictures : Hit the ">" Show Albums and stories" on the left side
        http://s807.photobucket.com/user/budm/library/

        TV Factory reset codes listing:
        http://www.badcaps.net/forum/showthread.php?t=24809

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          #5
          Re: Help: what are these SMD package components?

          The other numbers are very likely date codes

          Comment


            #6
            Re: Help: what are these SMD package components?

            Originally posted by budm View Post
            Those inductors are for the SMPS, I.E. U2 LT3633: https://www.analog.com/en/products/l...oduct-overview
            You can look up the spec sheet of other ICs then you can start checking Voltages
            thanks big time. One of the inductors of interest measures "fine" in terms of low dc resistance BUT the voltage seems strange on one leg at 1.xxx volts which doesn't seem right for the motherboard in general... as I can see for others, things like 5v, 8v, and 3.3.... so possibly that particular circuit / inductor has some form of issue. Hopefully, your "hint" will help get me to the issue. This surface rt has no 5v at the usb and also at the keyboard / dock / cover port (which supposedly is usb based)... but the two ports are not directly tied together (ie. metering does not indicate a direct connection, plus different areas of the motherboard). My guess is that the previous user was using the usb port to drive some device that stressed the drive circuit.... maybe.... although I have not spotted any "ugly" looking components visually.
            My actual thread on the surface rt is in the computer / mobile device forum.
            https://www.badcaps.net/forum/showthread.php?t=79072

            of course, the bad news is these are inside of "cans" and I am not sure that could do a repair / removal / replace. :-(


            One question Budm.... do these types of circuits usually have some form of fusing or does the design just "allow" for component failure? :-(
            Last edited by budwich; 09-07-2019, 06:56 AM.

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              #7
              Re: Help: what are these SMD package components?

              the other device in question is MS GD 2241 which I can't find in general search. does the "MS" portion indicate some form of microsoft specific IC?

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                #8
                Re: Help: what are these SMD package components?

                there are 1.2v and 1.8v logic devices - the reading may be fine.

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                  #9
                  Re: Help: what are these SMD package components?

                  oh oh... then I am looking in the wrong place. Make sense. I am still trying to trace the tracking / metering along the area to find out where the 5v gets lost for the usb stuff but it is tough with the can borders in place. thanks for the warning.

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                    #10
                    Re: Help: what are these SMD package components?

                    Did you try usb device on the usb port to see if the 5v appears. they sometimes use a ic to conrol the usb voltage. Sometimes there is just a fuse or resetable polyfuse.
                    Last edited by R_J; 09-07-2019, 10:36 AM.

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                      #11
                      Re: Help: what are these SMD package components?

                      I tried both a working charge cable to another device... no charge indication at the device. I then tried a usb flash drive with light indicator... no activity.

                      As you indicate, it could be likely that because the system doesn't "boot up" that there are some "switch component devices" that don't get opened / switched.

                      One 6 pin ic labeled as C5 UA is in the 5v path of the usb 5v circuit. I haven't found any info on it. I think it has 3.3v on one of the legs... so perhaps some form of step regulator / switch.

                      Comment


                        #12
                        Re: Help: what are these SMD package components?

                        sorry if I am dragging this thread around. Some of the questions are about devices but I understand that it is maybe running into specific trouble shooting. I do appreciate the great guidance.

                        Attached is a picture of the power management area.
                        There are some smd components that have like a "black paint / dot" on them... are they bad components (ie. burnt / burning) or are those some form of designation?

                        Further, in the picture, I traced the 5v pin from the cover dock usb pin (which never gets 5v) back to the area with the 5 pin device. One leg of that device has 5v volts on it but it appears that device never gets activated. Anyone know what it is... its label is UFC0E. There is the same device in the circuit at the usb port area.
                        Attached Files

                        Comment


                          #13
                          Re: Help: what are these SMD package components?

                          The ic labeled UF is likely a LDO, could be a AX6608-2.5V If pin #3 is not enabled, the output will be 0v.
                          That MSGD could be a gyro sensor ic
                          The black paint dot could be just glue for a component that was not fitted, they put down glue dots, then the component gets placed on the glue before it gets soldered
                          Last edited by R_J; 09-07-2019, 01:43 PM.

                          Comment


                            #14
                            Re: Help: what are these SMD package components?

                            OK... I guess I need to trace that enable.... got a feeling it will end up near / in the TI power management chip / ic.

                            Learning lots, great hints..... but not sure I (we) can save this unit. It might be deeper than a "non-schematic troubleshoot" can achieve but you never know unless you keep trying... :-)

                            Comment


                              #15
                              Re: Help: what are these SMD package components?

                              Originally posted by R_J View Post
                              The ic labeled UF is likely a LDO, could be a AX6608-2.5V If pin #3 is not enabled, the output will be 0v.
                              That MSGD could be a gyro sensor ic
                              The black paint dot could be just glue for a component that was not fitted, they put down glue dots, then the component gets placed on the glue before it gets soldered
                              looked at the spec for an ax6608 with the 5 pin package.... could be a similar device maybe.... BUT I never see any voltage on any of the pins in question. Basically only voltage present is on "pin 1". This is on both devices in the two areas. :-( Haven't been able to trace the pin 3 track to anything yet (via a meter)... I haven't removed the board to look at the back side to see if visually can follow tracking.

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