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  • uDrive signal points

    Howdy fellas.

    I've bought nearly 100 uDrive modules and desoldered the header from each for use in my hardware. The problem is that because of the first technique I was using in the past to desolder the pins, I ended up with 6 dead modules.

    I was using a desolderer bulb and the thru-holes came off where some of the pins were. I had wiggled a few of the pins to get it to turn lose, and well... I found out quick that the RX pin is pretty fragile. Later on I started to just heat the solder and pull each pin out with pliers with success. A $200+ lesson learned.

    I need to try to repair these uDrives by finding out where TX, RX, VCC and GND are on the board itself so I can solder a short jumper wire over depending on what thru-hole is bad on a given uDrive. I can clearly see that some of the thru holes are gone and I remember them coming off and being sucked into the desolder bulb.

    Can someone do a diagram that shows where I can connect my signals elsewhere on the uDrive board?

    A word of advice to anyone trying to desolder the header. First remove the plastic guard from the header by sliding it off carefully. Then heat each pin one at a time and slide it out of the uDrive board carefully. Works great. Then vacuum desolder the thru-holes.

    The built-in header is nice but it doesn't work well in all applications where the uDrive needs to be attached very solid to another board, as in wiggle-proof.
    --
    Roger Taylor

  • #2


    Not sure which revision of the uDrive you have but this should help. Verify the information below by comparing it to one of your 'good' uDrives

    TX - goldelox Pin 14
    RX - 68ohm Resistor, there's 4, so be careful, its the one that has the 'other side' connected to a 10k resistor
    VCC - One side of the 'big diode' (check against another uDrive for side)
    GND - Both the LEDs have one side to GND, find the common pins and you have GND
    Mark

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    • #3


      I had another idea.

      Ok, after cleaning my magnifying glass lens well and getting under a bright light I can see that the trace leading to the middle header pin through-hole dead ends with no ring attached anymore, so there's no contact if a pin is soldered in.

      So... I used the tiny extra magnifier (about the size of a U.S. 10 cent coin) on the lens to zoom in on the area more and I used my exacto knife to scrape the trace down to copper right near the through-hole.

      I'm crossing my fingers as the soldering iron is heating up. I should be able to let you know if I was able to salvage this otherwise good uDrive here in a few minutes.
      --
      Roger Taylor

      Comment


      • #4


        Another good way to desolder the header:-
        Hold the header in a pin vice so solder side is facing up.
        Run a little resin cored solder into the first pin as you are heating it,
        and use the iron at an acute angle, gently running up and down a few
        times to heat all pins together adding a little more solder if required,
        the fresh solder helps it all to start flowing.
        Once up to temperature simply lift the board of the header slowly so
        gravity will help pull the solder out of the holes and stay with the pins.
        then just use a bit of solder wick to clean out the holes.

        If you contact 4D sales they may be able arrange to supply of any further units without header.
        Regards,
        Dave

        Comment


        • #5


          I had no luck with 2 of the modules that had the middle pin's ring missing from the trace. I scraped the trace and tried to make sure the solder was between it and the new pin but apparently it either didn't connect or there's something else wrong with both modules.

          Thanks... I really need to get these modules without the headers soldered in. I need 75-100 more uDrives over the next 6 months. I ordered some from Saelig one time and they came without the headers but the firmware was older.
          --
          Roger Taylor

          Comment


          • #6


            Speaking of headerless uDrives, can you confirm whether Saelig's stock of uDrives have the previous firmware (the 2GB R22 firmware?) based on their product page?

            http://www.saelig.com/ST/ST001.htm
            --
            Roger Taylor

            Comment


            • #7


              You'd have to check with suppliers, I imagine it depends upong how many they are selling and the meticulousness of their FIFI stock management.

              IIRC we did sell them without headers installed once upon a time... Then people complained about not being told that 'some assembly was required'.
              Mark

              Comment


              • #8


                Just an update: I saved one of my uDrives which still had the header attached but there was something wrong with the firmware and past attempts to update it wouldn't work, but for some reason the newest firmware works. Go figure. $29 saved.
                --
                Roger Taylor

                Comment


                • #9


                  Another update...

                  I repaired one of my bad uDrives! Mind you, it took over an hour, the smallest copper wire strand known to man (taken from a twisted group wire), some super still hands, a good magnifying glass, and lots of light overhead.

                  I had to first attach a spec of solder to the end of the copper wire, then I took my exacto and scraped the protective coat from the tiny through-hole that's nearest to the 68ohm resistor for RX, soldered the wire to the through-hole (it won't go in very far) then ran the wire to the RX header pin.

                  I just hooked up the USB/TTL cable and loaded the FAT Controller software, and damn if it's not flashing those red and green LEDs like a Christmas tree, all commands seem to be working.

                  If I can do this to the other bad uDrives, we're talking over $200 (considering shipping from Australia) saved. If I can save 3 out of 5, that's a blessing.

                  Again, to those trying to desolder the header from a uDrive... be very careful not to overheat or you might lose the through-hole rings from either side of the board for any given pin, especially the middle pin for some reason.
                  --
                  Roger Taylor

                  Comment

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