7 Replies Latest reply on May 22, 2020 8:59 PM by ninjatrent

    Name this part

    ninjatrent

      I have recently purchased a Raspberry Pi 4 (4GB). Upon close inspection of the board, I've noticed one of the parts has fallen off in the package.

       

      It is a very small part and I am at the limits of available magnification. Is there anyone that can help me identify this part?

        • Re: Name this part
          shabaz

          Hi Trent,

           

          I have a Pi 4 near me, and you're right, that part is tiny! : )

          I *think* it's a capacitor but not 100% sure. It measures approx 1.3 kohm in one direction, and 1.5 kohm in the other, in-circuit (since I didn't want to desolder it - it is dust sized : )

          Anyway, it's likely a capacitor, because continuity testing on each end of it shows that one end is connected to pin 1 of the 40-way GPIO header, and the other end is connected to pin 9. These are the +3.3V and GND pins respectively, so it's possible it is a capacitor across the supply rail. The reason why it appears in the middle of nowhere, is because on the other side of the PCB there is some IC there, but I don't know what it does. The IC is next to 4 resistors and nothing else, It could be some glue logic maybe. It doesn't seem to be a voltage regulator or anything.

          If you cannot solder it back on, if the Pi is still working, then I wouldn't worry about it, but worth holding on to that part and measuring it at some point if you can, to confirm it is a capacitor. To do that, just measure with the ohms setting, and if the resistance is very high (not measurable) in both directions, then it is a capacitor.

          8 of 8 people found this helpful
          • Re: Name this part
            Fred27

            I'd agree with Shabaz that it's a decoupling capacitor. I suspect the Pi will work fine without it, but if you feel like practicing your soldering...

             

            The component on the other side is a rectangular 16 pin QFN package marked "uK RX", but I'm not sure what it is.

            5 of 5 people found this helpful
              • Re: Name this part
                ninjatrent

                I'm not sure if I can solder this.

                 

                The part is about the size of the period at the end of this sentence .

                  • Re: Name this part
                    Fred27

                    Unless you have a microscope, it's likely to be frustrating. Also, shorting out those pads could cause problems. If your Pi is running ok then count yourself lucky that you dislodged a non-critical component. How did you do it, by the way?

                    1 of 1 people found this helpful
                      • Re: Name this part
                        ninjatrent

                        I haven't powered on, it arrived damaged in damaged packaging. I noticed the absence of the part when looking for damage on the PCB. It was loose in the box. I also noticed Raspberry Pi has stopped sending the boards in antistatic bag.

                         

                        I've contacted customer service.  Waiting for a replacement and return box.

                         

                        Everything else in the order was undamaged. The Raspberry Pi 4 box is clearly damaged. I don't understand why the person who put the order together would even send out a product in damaged packaging. It looks bad. I doubt it arrived from Raspberry Pi facilities in this condition.

                  • Re: Name this part
                    colporteur

                    Ugh crap! I hate having parts left over after a reassembly.

                     

                    I pulled out my Pi4B to take a look at the component. I've hand soldered 402 LED's and figured that was small. This part is smaller than aphid droppings.

                     

                    If you successfully hand solder the component you deserve some kinda E14 badge. We can call it Flea Chastity Belt Assembly Badge or something small like that.

                      • Re: Name this part
                        ninjatrent

                        I have gotten a migraine headache just trying to identify the part under a magnifying glass.

                         

                        Even the very fine Hakko tip on hand is not small enough for this. Rework would blow the part away like dust (and one is not available). Maybe solder paste and oven would work but I don't want future meals to taste like flux and plastic.

                         

                        I should get the headache badge