Author Topic: can you fix a very small pad on a pcb ?  (Read 458 times)

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Offline vNawar

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can you fix a very small pad on a pcb ?
« on: March 28, 2019, 07:50:01 pm »
there was a button like the other one in the picture but it broke off.
is there any way to fix this?

« Last Edit: March 28, 2019, 08:04:41 pm by vNawar »
 

Offline helius

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Re: can you fix a very small pad on a pcb ?
« Reply #1 on: March 28, 2019, 08:18:28 pm »
It can be fixed with enough finesse and skill.
The adhesion between the copper pads and the PCB substrate is broken, so adhesive needs to be used to reconnect pads to the board. A quick setting epoxy such as Araldite is frequently used for this. The new pads can be cut out of thin copper foils: pre-cut foils in several shapes are available from CircuitMedic and Pace Cir-Kit. Solder mask is scraped from the remaining traces and the foils are bonded to them using pressure and heat and solder.

It is also possible to re-connect the traces by micro-soldering fine wires, or using silver conductive ink. The button needs to be supported by adhesive so it doesn't come off again.
 

Offline DaJMasta

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Re: can you fix a very small pad on a pcb ?
« Reply #2 on: March 28, 2019, 08:30:10 pm »
Definitely possible, as said, but tricky because it's such small work.  You need to get replacement pads (probably easier than removing and trying to reuse the ones on it) soldered to the existing traces - probably copper foil for the pad, then scraping away a bit of the solder mask and solder bridging them to the pads - then you need a reliable adhesive to attach the switch and hold it in place.  Ideally, you want it to be stronger than it was before, since it already broke once, but you can't rely on the adhesion of the new pads to do as good a job as the factory ones, so some extra glue around it or in the board cutout would help to fix it.

Again, though, it's probably going to take some time spent under a microscope/jeweler's loupe with a sharp knife and a bunch of patience.  The hard part is actually doing it because of the size.
 

Offline Wimberleytech

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Re: can you fix a very small pad on a pcb ?
« Reply #3 on: March 28, 2019, 09:19:24 pm »
I would solder 30 gauge wire to the switch contacts and then epoxy the switch in place.  Then connect the other ends of the wires to the appropriate locations.  Trying to rebuild the pads looks like a losing battle to me.
 

Offline coppercone2

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Re: can you fix a very small pad on a pcb ?
« Reply #4 on: March 28, 2019, 10:00:49 pm »
you can dip the wire in  tacky glue too. Wait for epoxy thats kinda starting to cure.
 

Online eKretz

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Re: can you fix a very small pad on a pcb ?
« Reply #5 on: March 28, 2019, 10:22:03 pm »
Yeah you should be able to get that fixed. I was thinking like super tiny smd cap pads from the thread title. That would be tough. This should be easy as long as you have the experience to do it, but still going to be time-consuming. It's fiddly work.
 


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