Replace Micro-USB Port With Only a Soldering Iron
by ErinTheSmall in Circuits > Soldering
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Replace Micro-USB Port With Only a Soldering Iron
This instructable documents a useful hack to desolder and replace failing Micro-USB (or USB-C, mini, etc!) ports without use of hot air, solder wick or solder suckers. - Just a soldering iron and some wire!
(I tweeted about this a week ago, people seemed to find it useful so here it is as an instructable!)
The method is definitely a hack, and not best practice at all, if you have access to more advanced tools you can absolutely do this a better way.
Supplies
Mandatory:
- Soldering iron - Almost any will work, in this case I use a Pinecil running at 30W.
- Something to clean your iron tip - I use brass wool.
- Solder - The lower the melting temp the better.
- Something to hold your pcb still - I use a vise, but even blu-tac on a desk should work fine.
- Replacement port - This can be salvaged from another device using the desoldering method detailed below.
- A short piece of solid core wire - Copper is preferable, but I use a snipped lead from a diode.
Optional Extras:
- Solvent to clean flux - Optional but strongly recommended if you have it.
- Solder wick / Braid - Optional but may be useful when putting a new port on.
- Multimeter - Optional but recomended.
- An old usb cable to cut up for checking continuity - Optional but recomended.
Making a Plan
We need to identify the joints that need heating to remove the port, and plan the wire route that will channel heat and melt them all at once:
- Most SMD USB ports will have 2-4 mechanical joints either side of their main body (and in this case a joint underneath), as well as several data pins.
- Try to work out a path to join all these spots that need heat with a small piece of wire, in this case by bending a C shape.
note: Pads underneath the main body of the connector will melt if spots nearby are heated, but may make the process take longer.
Forming the Wire
- Cut a length of your wire roughly to length.
- Bend it to match the shape you planned in step 1.
Tinning Joints and Attaching the Wire
- Add a liberal amount of solder to all the joints.
- Slide the wire into place.
- Join the wire to each blob of solder.
note: Don't worry about making neat joints or bridging pins! this will all be gone soon.
Removing the Port
Apply gentle pressure to the connector, pushing towards the edge of the board until the connector slides off.
If your connector has through hole mechanical pins, or plastic locator pins that extend all the way through the pcb, tweezers may be needed to pull upwards instead of pushing with the iron.
note: This took about 7 seconds for me, with my iron running on a 30W USB-C PD power-bank, which is not optimal, it should be much faster using a higher wattage iron, or higher wattage settings if supported.
Cleaning Up
To attach a new port we'll need to first clean the excess solder off the pads:
- With a clean iron, drag the tip across the mechanical connection pads, taking solder with it.
- Clean the solder off the tip using your brass wire or sponge.
- Repeat this until the pads are clean.
- Use solvent to clean up any flux left behind. - Optional but recommended (I didn't have any to hand).
Make sure to leave a little solder on the data pin pads!
If you have solder wick / braid to hand this will make this much faster and clean.
note: If you are desoldering a port to be re-used, make sure to clean the solder off the bottom of the body too.
Attaching the New Port
Now we'll put the new port in place and solder it in:
- Place the connector on the board - Connectors will often have locator pins, so make sure they are in their holes.
- Secure the connector in place temporarily - Optional, I did this without but it can help. (this could be with blu-tac, tape or pressing with tweezers).
- Gently connect the mechanical joints using a little solder.
Connecting the Data Pins and Inspecting
This is the hardest step, and will require some care because if it goes wrong the connector may need to be removed and placed back on (if you don't have solder wick / braid to hand)
- Clean your tip as much as you can so no loose solder is sticking to it. - THIS IS VERY IMPORTANT
- Gently press down on the data pins until the solder left on the pads beneath melts, and joins them.
- Check that the data pins are joined properly, and have no solder bridges between them.
If your data pins bridged you can attempt to remove the solder by swiping the iron across it, if this does not work solder braid / wick will be needed.
If you can't get the bridge off and don't have wick, you can desolder the port and try again with less solder on the pads, and absolutely no solder on the iron tip
Testing Continuity
This step is optional but recommended, if you don't have a multimeter be extra careful pins are not shorted.
We need to check that all the data pins are connected properly to the connector internals, and not bridged:
- Cut the old usb cable and expose the internal wires.
- Strip the wire tips so you can probe them with the multimeter (point a).
- Plug the cable into the new port.
- Choose a pin and follow it's trace to a point that can be probed on the board (point b) - a testpoint or component lead generally.
- Work out which wire should correspond to the pin, and check that they are connected with the multimeter. - This can generally be found by googling "<port> pinout", in this case "micro usb pinout.
- Touch probe b to each individual pin's traced connection point and check that none are bridged to the first pin.
- Repeat this for the other pins, checking for continuity to the right wire and no bridges to the other pins.
Finished! (mostly)
Hopefully all went well, and you have a fully functional connector attached to your board now!
If you have solvent on hand, now's the time to clean up the flux we left around the connector (I didn't have any to hand when making this).
I hope you found this Instructable useful! 🧡
note: My end result is pretty messy as the port I used was salvaged, and I had no flux cleaner, I'm sure you can do much better!