How do I fix lifted PCB pads?

[Kavik]

I initially soldered the backslash key switch in slightly crooked because every plate has to accommodate both ANSI and ISO enter for some reason (and thus has no plate support and a quarter of a pad to solder to for that switch).

I had a hard time desoldering it for some reason. I eventually just used a screw driver and punched the switch out. Apparently, the switch took both pads with it (see photos below. It looks as though the pads are still stuck to the switch pins). I put a new switch in and the solder doesn't stick to one side (since there's no metal to stick to), but it doesn't respond even if I get the solder in contact with the PCB (since there's no metal to contact).

What is the best way to fix this?
-Should I put the original switch back in somehow (not sure that would help since the pads are no longer connected to the PCB)?
-Jumper wires (no idea how to do this)?
-Is there some way to reconnect the pads to the PCB assuming those are the pads still on the switch?
-Some other alternative?

Photos:
https://imgur.com/o7GMrqn
https://imgur.com/wNcf8Ds
https://imgur.com/wXdVrDY
https://imgur.com/928Bkxt

[nmur]

I had some ruined pads on a pcb not too long ago

my fix is detailed here: https://geekhack.org/index.php?topic=95766

[Kavik]

I had some ruined pads on a pcb not too long ago

my fix is detailed here: https://geekhack.org/index.php?topic=95766

Thanks, your pictures raise a question: are the traces the light green strips between the dark green lines, or are they the dark green lines themselves?

I think a big issue with this is going to be stabilizing the switch and getting it straight since that was the whole problem to begin with.

[nmur]

I had some ruined pads on a pcb not too long ago

my fix is detailed here: https://geekhack.org/index.php?topic=95766

Thanks, your pictures raise a question: are the traces the light green strips between the dark green lines, or are they the dark green lines themselves?

I think a big issue with this is going to be stabilizing the switch and getting it straight since that was the whole problem to begin with.

the light green strips cover copper traces, the dark green sections separate those traces

because your pad is gone, you'll have to carefully scrape away the top layer on the trace that the pad used to connect to, like i did in my photo here:


ie you need to scrape away this red part to reveal the copper underneath, then put some solder on it


then after the clean the switch and put it back, you'll need to build up a big glob of solder that eventually latches itself onto the trace's solder and connects them up


just a heads up tho, this **** is pretty difficult, and will be even more difficult without the proper tools (iron, heat setting, tip, etc)

[Blaise170]

Something you can also try is to use a silver PCB repair pen, though this will depend on the damage how effective it is.

[Kavik]

I had some ruined pads on a pcb not too long ago

my fix is detailed here: https://geekhack.org/index.php?topic=95766

Thanks, your pictures raise a question: are the traces the light green strips between the dark green lines, or are they the dark green lines themselves?

I think a big issue with this is going to be stabilizing the switch and getting it straight since that was the whole problem to begin with.

the light green strips cover copper traces, the dark green sections separate those traces

because your pad is gone, you'll have to carefully scrape away the top layer on the trace that the pad used to connect to, like i did in my photo here:

Show Image

ie you need to scrape away this red part to reveal the copper underneath, then put some solder on it
(Attachment Link)

then after the clean the switch and put it back, you'll need to build up a big glob of solder that eventually latches itself onto the trace's solder and connects them up
(Attachment Link)

just a heads up tho, this **** is pretty difficult, and will be even more difficult without the proper tools (iron, heat setting, tip, etc)

Thank you for the explanation and pictures. Those help a lot.

Something you can also try is to use a silver PCB repair pen, though this will depend on the damage how effective it is.

This opens up yet more questions. Would it be possible to redraw the pad with one of these silver pens? Or could I lift a pad from another PCB, glue it down, and draw the trace back to the new pad? That might be extremely difficult even if technically possible. Is it possible to solder to the drawn on silver?

Sorry if these are dumb questions. I know just enough to be dangerous apparently. This is my fifth time installing switches, but all the other times have been uneventful.

Also, based on my pictures of the removed switch, I think the pad on the other hole might be missing too despite being soldered; however, I think the trace for it is on the top of the PCB. I hope that doesn't complicate it further.

[Delirious]

No need for fancy pad replacement, just think of it as hand-wiring, aka jump wire,figure out the broken links and link them together with copper wire.

This is an example of one of my build. I have a Leeku’s 1800 pcb that doesn’t support 2u numpad plus sign, so I just drill the pcb and link it back into the chain.

I also drill my The Time pcb because it doesn’t support alps stepped caps. Then once again jump-wire the broken links


https://imgur.com/a/lOy4arx

Also as far as switch stability, just hot glue the back of it

[killyou]

I broke 2 soldering pads when installing holtites into my Pok3r. I simply connected PCB to USB port and tried to short the other working soldering pad with the nearest diode of the one that I broke to see if the key registers. If I had a match then I run a silver/whatever wire from the holtite that I installed to the diode directly. You can do that the same by soldering the wire to one of the switch legs.

[Kavik]

I had some ruined pads on a pcb not too long ago

my fix is detailed here: https://geekhack.org/index.php?topic=95766

Thanks, your pictures raise a question: are the traces the light green strips between the dark green lines, or are they the dark green lines themselves?

I think a big issue with this is going to be stabilizing the switch and getting it straight since that was the whole problem to begin with.

the light green strips cover copper traces, the dark green sections separate those traces

because your pad is gone, you'll have to carefully scrape away the top layer on the trace that the pad used to connect to, like i did in my photo here:

Show Image

ie you need to scrape away this red part to reveal the copper underneath, then put some solder on it
(Attachment Link)

then after the clean the switch and put it back, you'll need to build up a big glob of solder that eventually latches itself onto the trace's solder and connects them up
(Attachment Link)

just a heads up tho, this **** is pretty difficult, and will be even more difficult without the proper tools (iron, heat setting, tip, etc)

Nmur, thank you!!! I just did this successfully. It actually wasn't all that difficult. I just scraped the trace with a pocket knife until I saw silver, bent the switch pin as close as I could get it, and soldered to it. The only tricky part was heating up the trace enough that solder would stick to it. You saved me $55 on a new PCB and the huge pain of desoldering all the switches.

[nmur]

I had some ruined pads on a pcb not too long ago

my fix is detailed here: https://geekhack.org/index.php?topic=95766

Thanks, your pictures raise a question: are the traces the light green strips between the dark green lines, or are they the dark green lines themselves?

I think a big issue with this is going to be stabilizing the switch and getting it straight since that was the whole problem to begin with.

the light green strips cover copper traces, the dark green sections separate those traces

because your pad is gone, you'll have to carefully scrape away the top layer on the trace that the pad used to connect to, like i did in my photo here:

Show Image

ie you need to scrape away this red part to reveal the copper underneath, then put some solder on it
(Attachment Link)

then after the clean the switch and put it back, you'll need to build up a big glob of solder that eventually latches itself onto the trace's solder and connects them up
(Attachment Link)

just a heads up tho, this **** is pretty difficult, and will be even more difficult without the proper tools (iron, heat setting, tip, etc)

Nmur, thank you!!! I just did this successfully. It actually wasn't all that difficult. I just scraped the trace with a pocket knife until I saw silver, bent the switch pin as close as I could get it, and soldered to it. The only tricky part was heating up the trace enough that solder would stick to it. You saved me $55 on a new PCB and the huge pain of desoldering all the switches.

excellent! it's a good feeling lol

well done sir



Sent from my ONEPLUS A5000 using Tapatalk

[johngodsmith]

Anyone tried conductor pens? I've read that the fix is only temporary though

[Kavik]

Unfortunately, this fix was only temporary. After an hour or so of use, the backslash key stopped registering. What's weird is that it still works if I press on the very top of the keycap very deliberately, but it doesn't work at all if I press the switch stem without a keycap. I guess I'll have to take it apart and look at it again.

[bball2]

Possibly a dumb idea, but can you just connect a piece of solder wire from the broken switch to a key that you don't use?

I lifted the pad on my space bar on a wkl build and I was thinking of just connecting it to the key to the immediate right which I never use and have that programmed as the spacebar.

[Blaise170]

Possibly a dumb idea, but can you just connect a piece of solder wire from the broken switch to a key that you don't use?

I lifted the pad on my space bar on a wkl build and I was thinking of just connecting it to the key to the immediate right which I never use and have that programmed as the spacebar.

How do you propose connecting a strand of solder to separate pads without melting the entire strand?

[tp4tissue]

Possibly a dumb idea, but can you just connect a piece of solder wire from the broken switch to a key that you don't use?

I lifted the pad on my space bar on a wkl build and I was thinking of just connecting it to the key to the immediate right which I never use and have that programmed as the spacebar.

You can do that, but you probably don't need to.

Just do what the OP is doing,  scratch the top of the traces lightly until you see shiny -yellow-.

This is on the space bar traces which connect to the pads you've lifted.

Make sure to scratch only the trace, and not either side of the trace, because that's probably a ground plane.. and if you solder it to the ground plane, it won't work.

[bball2]

Cool, thanks for the tips, I'll give the scratch method a try.

@Blaise170, basically after some solder is melted leave the strand of solder right there then do the same to the other side.

[Blaise170]

Cool, thanks for the tips, I'll give the scratch method a try.

@Blaise170, basically after some solder is melted leave the strand of solder right there then do the same to the other side.

Doing that is far harder than you might think. It's way easier to just buy jumper wires and solder those to the pins. You can get bundles on eBay for like $4-5.

[Kavik]

Since the key was not very responsive, I was actually going to do that (there are lots of unused switch slots around ENTER to accommodate different layouts). In fact, I think that's my only option at this point because in trying to redo what I did last time, I've scorched the PCB in that area beyond use. I think I need to get some solder that doesn't have a flux core because every time the solder didn't stick the first time, it left a crap load of residue that I had to scrape through again. I'm afraid I've scratch out the trace at this point.

Or I could just order another PCB and use this one as a bonus if I get it to work.

None of this would've happened if the switch plate actually supported the backslash key or if Kailh switches had the extra PCB mount legs or if I'd been paying attention. 

Do I need jumper wires specifically? I cut a section of a Molex to SATA power converter to use, but it might be tricky because it's made up of thin fibers inside that I had to twist up, so I'm not sure it'll work.

If I do this, I'll also have to learn to program with QMK to remap that key, which looked needlessly difficult the last time I checked (build a Linux VM inside Windows and compile source code, etc.)

[pixelpusher]

I'm confused.  I thought you could just go from the lifted pad to the corresponding polarity on the diode of the switch and then connect the other pin to any adjacent switch

and any wire should work, you just need to use stranded and not solid core.  Solid core will break stuff if tugged on.  I've used USB wires in the past.

[Kavik]

Ok, guys, I have finally fixed it for good (I hope).

As mentioned earlier, I snipped two sections of a Molex-to-SATA power cable and soldered them to the BACKSLASH switch and soldered the other end to unused key's pads. At first, I connected them to the unused pads next to ENTER, but the QMK Configurator did not allow me to access that spot on the PCB separately from the main ENTER. I probably could have figured out a way to set up a QMK environment and make it work, but I am dumb and lazy and would rather just use the configurator. I noticed that the configurator does allow for a split backspace, so I desoldered the wires from ENTER and connected them to the outermost BACKSPACE spot. Then I remapped BACKSPACE to BACKSLASH. On the keymap it's basically the reverse of what a split backspace layout would look like (BACKSPACE on the left and BACKSLASH on the right), which still works since I'm using a regular ANSI layout. I put some electrical tape around the wires and at the solder point since a stabilizer screw goes right on top of one of them.

Crisis averted (for now).

Thanks for all the help, everyone. This was a pain in the butt, but I wouldn't have been able to fix it without your suggestions.

[tp4tissue]

Ok, guys, I have finally fixed it for good (I hope).

As mentioned earlier, I snipped two sections of a Molex-to-SATA power cable and soldered them to the BACKSLASH switch and soldered the other end to unused key's pads. At first, I connected them to the unused pads next to ENTER, but the QMK Configurator did not allow me to access that spot on the PCB separately from the main ENTER. I probably could have figured out a way to set up a QMK environment and make it work, but I am dumb and lazy and would rather just use the configurator. I noticed that the configurator does allow for a split backspace, so I desoldered the wires from ENTER and connected them to the outermost BACKSPACE spot. Then I remapped BACKSPACE to BACKSLASH. On the keymap it's basically the reverse of what a split backspace layout would look like (BACKSPACE on the left and BACKSLASH on the right), which still works since I'm using a regular ANSI layout. I put some electrical tape around the wires and at the solder point since a stabilizer screw goes right on top of one of them.

Crisis averted (for now).

Thanks for all the help, everyone. This was a pain in the butt, but I wouldn't have been able to fix it without your suggestions.

WTH kavik, we did not tell you to do that at all.. hahahaha

[Kavik]

Ok, guys, I have finally fixed it for good (I hope).

As mentioned earlier, I snipped two sections of a Molex-to-SATA power cable and soldered them to the BACKSLASH switch and soldered the other end to unused key's pads. At first, I connected them to the unused pads next to ENTER, but the QMK Configurator did not allow me to access that spot on the PCB separately from the main ENTER. I probably could have figured out a way to set up a QMK environment and make it work, but I am dumb and lazy and would rather just use the configurator. I noticed that the configurator does allow for a split backspace, so I desoldered the wires from ENTER and connected them to the outermost BACKSPACE spot. Then I remapped BACKSPACE to BACKSLASH. On the keymap it's basically the reverse of what a split backspace layout would look like (BACKSPACE on the left and BACKSLASH on the right), which still works since I'm using a regular ANSI layout. I put some electrical tape around the wires and at the solder point since a stabilizer screw goes right on top of one of them.

Crisis averted (for now).

Thanks for all the help, everyone. This was a pain in the butt, but I wouldn't have been able to fix it without your suggestions.

WTH kavik, we did not tell you to do that at all.. hahahaha

Bball2 did, followed by the suggestion of jumper wires by Blaise170 and confirmation of my substitution of Molex/SATA wire by pixelpusher. I'd considered the idea before reading it, but their info helped me know it was plausible and I wouldn't screw it up if I tried.

For whatever reason, scratching the trace open and soldering directly to it only worked for an hour or so, and then the switch stopped responding reliably.

[tp4tissue]

For whatever reason, scratching the trace open and soldering directly to it only worked for an hour or so, and then the switch stopped responding reliably.

Hrrrrmm.. it could be a few things.

If the switch isn't inserted all the way, then the misalignment would cause the joint to fail when pressed.

The scratched trace contact isn't 100% clean (not fully scratched).

There might not be enough surface area scratched open for the solder to properly bond.

DID you rub the scratched contact with rosin.. you gotta rub it down with alcohol, then rosin.

[jcoffin1981]

Aren't there support legs on the bottom of the switch that fit into the PCB? If these are intact the switch should be sturdy. Regardless it sounds like poor design. 

I have a technique I use when the pad is lifted.  I heat the solder joint to liquid and insert a short piece of copper wire and make contact with the pad or exposed trace on the opposite pad (switch side) of the PCB.  I have to sand the wire to a point to make it fit. This is visibly neater as I don't like the visible wires protruding from the pcb.  In the event I can't make contact I wire the leg to an adjacent switch or the corresponding diode.

[SpAmRaY]

Aren't there support legs on the bottom of the switch that fit into the PCB? If these are intact the switch should be sturdy.

They're plate mount switches they dont have the extra legs, see pics in the OP.

Sent from my SM-G930V using Tapatalk

[Kavik]

For whatever reason, scratching the trace open and soldering directly to it only worked for an hour or so, and then the switch stopped responding reliably.

Hrrrrmm.. it could be a few things.

If the switch isn't inserted all the way, then the misalignment would cause the joint to fail when pressed.

The scratched trace contact isn't 100% clean (not fully scratched).

There might not be enough surface area scratched open for the solder to properly bond.

DID you rub the scratched contact with rosin.. you gotta rub it down with alcohol, then rosin.

Ah, any of those might have been the case. It was so small that it was hard to see; I just scratched until I saw silver. I didn't clean or prep the trace at all, so it's possible the bond broke just enough to disrupt the circuit when I didn't press really hard.

And, yeah, Kailh only has plate mount switches AFAIK, at least in the BOX variants. I was tempted just to stick a Zealio in there so that it would be straight and feel similar. But everything worked out.