Fixing burnt solder pads?

[muon]

Hey all - bought a used WKL board recently and it turned out to be pretty borked. The traces look fine so I'm assuming the solder pads are pretty burnt, though I'm not entirely sure. I did manage to fix caps just by fixing solder joints but the other broken keys still aren't being responsive no matter what I try with solder. I'd really appreciate anyone's assistance in what I can do to fix this - I know I should be jumper wiring but I'm not sure from where to where.

Here's an album with pictures of the PCB: http://imgur.com/a/mp4Ev

The keys that don't work are:

7 8 0 - = Backspace
U I P [ ] \
J K ; ' Return
M , / RightShift
RtCtrl RtAlt RtWin Fn

[xtrafrood]

Whoa, is there solder on the RALT switch? Looks like solder is on plastic base of that switch, what in the world

[muon]

Yeah, not too happy about the state of this board 

[SpAmRaY]

Not sure how you can tell if you've got burnt pads with all the solder piled up like that.

I'd desolder first and see what's left.

Was it sold as being in working condition?

[muon]

Can't tell, just assuming because the traces look fine and I've tried extensively to touch up the solder jobs on the non-functional keys. Is there anything else it feasibly be?

[SpAmRaY]

Can't tell, just assuming because the traces look fine and I've tried extensively to touch up the solder jobs on the non-functional keys. Is there anything else it feasibly be?

Well just piling the solder up won't necessarily make it work. To me it looks like you've got way too much solder on those switch pins.

It could also be problems with firmware and/or the switches themselves.

Do you have a digital multimeter? If so you can test the switches.

[ghostjuggernaut]

Looks like the burnt part you are talking about is just the flux from soldering. It also look like there are a few cold joints.

I would buy a rosin pen and try reflowing the joints. You can clean up the flux using isopropyl, the higher % the better.

[muon]

Looks like the burnt part you are talking about is just the flux from soldering. It also look like there are a few cold joints.

I would buy a rosin pen and try reflowing the joints. You can clean up the flux using isopropyl, the higher % the better.

The orange stuff is melted rosin, I think. I'm just kind of assuming that it's burnt because my best attempts aren't fixing it  . Would you mind pointing out the cold joints you see?

Well just piling the solder up won't necessarily make it work. To me it looks like you've got way too much solder on those switch pins.

It could also be problems with firmware and/or the switches themselves.

Do you have a digital multimeter? If so you can test the switches.

I actually removed a lot of solder and tried to make the rest of it flow onto the pads, but that's definitely a possibility. Wish I had a multimeter, might go see if I can borrow one from a friend.

Thanks guys for the help! I'm gonna take another shot again tonight 

[tp4tissue]

/headscratch

are you using lead free ?

It doesn't look like the solder is stuck on too well..

[ninjadoc]

RtCtrl RtAlt RtWin Fn  two diodes are sideways and one end is not attached to the pad. There is also a missing diode in this area.

There is a pile of solder to the left of the right control that should be removed. I suspect you need a diode there.

Fn key is bad because of the sideways diode

Enter key - one end of the diode either doesn't contact the pad at all or has poor contact

7 8 0 - = Backspace  sideways diode, check upper poles of diodes,
7 8 check upper pole of the diode, switches need re-flowing, solder joints are probably cold

U I O P appears that the upper pole of the diode isn't soldered

I think several of the diodes aren't soldered on both ends. Multiple switches either have piles of solder or they open areas where it didn't flow properly ( like F D R T L alt L win  )

missing the diode for L shift

there is more I could say but that will get you going.
I would take as much solder off of the switches as you are comfortable with.
Next reflow every solder joint on the switches. You do realize that none of the switches are seated properly?
Then get a loupe
( http://smile.amazon.com/Illuminated-Magnifier-Construction-Kare-Kind/dp/B00YBHQ7X2/ref=sr_1_3?ie=UTF8&qid=1464218659&sr=8-3&keywords=jewelers+loupe)
and look at all of those diodes. You are missing two I believe, two or maybe three or sideways, and several don't appear to have been soldered on both ends.
You also have two or more melted stabilizers.
If those are Zealio's- given the clear bottom - you probably have some ruined switches. If they get too hot (obviously some did since there is melted solder on them ) they bottom of the switch can warp distorting the contacts. They will either "chatter" or just not work. I will bet you that is a problem with some of the switches.
Don't worry about a multimeter yet, just fix the basics and see what you have. If I'm right about these being Zealio's, pull every switch that has solder on the base thatdoesn't work after you done the preceding steps.

I hope you didn't pay too much for this board - I would probably throw it away. I could fix it but it would be a real pain in the ass.

[ninjadoc]

Also be methodical about it. Don't jump from place to place. That way you can keep up with what you are doing and what you've finished.

[tacnificent]

I hope you got a good deal.  Unless it's specifically to practice desoldering, not sure it's worth salvaging.

[muon]

I did not get a good deal at all

Thanks for the advice ninjadoc, I will try my best...

[Melvang]

Another thing to look into, those switches don't look like they are fully seated into the PCB.  PCB mount switches get firm, then pop into place.  It actually took much more force than I anticipated the first time I installed PCB mount MX.

[tp4tissue]

Another thing to look into, those switches don't look like they are fully seated into the PCB.  PCB mount switches get firm, then pop into place.  It actually took much more force than I anticipated the first time I installed PCB mount MX.

are these cherry switches on muon's keyboard ?

I'm thought they looked like they're not in all the way either.. but then I thought maybe they're some other switch..

[muon]

Yeah, these are Zealios. I noticed that too

Hoping to just desolder the Zealios and cut my losses at this point I suppose.

[tp4tissue]

Yeah, these are Zealios. I noticed that too

Hoping to just desolder the Zealios and cut my losses at this point I suppose.

well don't be discouraged, i mean..

the picture just looks weird to me though..

you are SURE that the copper pads were shiny and clean before you started soldering?


Also, it may be some other problem, if so many keys don't work.

[muon]

I bought this 'used' so I couldn't say.

The diodes look fine to me now except a couple of sideways ones which I'm about to fix so yeah it might be something else, I'm not sure how much I care to troubleshoot this thing anymore 

[tp4tissue]

I bought this 'used' so I couldn't say.

The diodes look fine to me now except a couple of sideways ones which I'm about to fix so yeah it might be something else, I'm not sure how much I care to troubleshoot this thing anymore 

did it come broken? or did you break it.. ?

[muon]

It came broken

[appleonama]

It came broken

did you at least get a good deal on it?

[muon]

No, not really, I don't mind too much though... especially if I can salvage these Zealios

[tp4tissue]

if that many keys don't work, and it came broken

that means the traces are damaged some where..

it's likely not the soldering.


Follow the traces. and check the controller pins.

[SpAmRaY]

No, not really, I don't mind too much though... especially if I can salvage these Zealios

With all that soldering there's a chance those switches got damaged from the heat.

if that many keys don't work, and it came broken

that means the traces are damaged some where..

it's likely not the soldering.

Follow the traces. and check the controller pins.

Did you see the photos? Between the diodes, blobs of solder and switches not being seated all the way, the traces are the last thing to worry about.

[jcoffin1981]

There is a learning curve when learning to solder.  With the amount of labor it would take to get this board working again it's probably not worth it, if it's not damaged beyond repair, but it could be a good learning experience.  If you desolder a switch and solder a 4 or 5 inch piece of wire to each lead, you can play with it and make contact with various points on the traces, pad, and diodes to see if it will still work.  There is also usually a pad on the opposite side of the board (the switch side) than can be made contact with as well.  The switch lead goes through the middle of the hole and does not make contact there, so you have to be creative to make this work. 

There are also ways to wire switches to adjacent working switches, but I have never used this technique.  Others can advise you on this and there are other posts about this as well. 

[muon]

I'm very familiar with soldering, just not too familiar with the whole jumper wire thing that people do when they burn traces and the like, which is kind of what I'm under the assumption I need to do here if I wanted to get this PCB working.

After examining the board it looks like the diodes are definitely soldered in place save for two that have been twisted sideways. It might be the fact that the switches aren't seated fully into the plate, too - all in all I'm probably just going to desolder the Zealios as it appears all but one are functional.

[SpAmRaY]

After you desolder the switches you might as well test the pads to see if they are working or not. Assuming the pads don't get destroyed during desoldering.

I just plug the board in with only the diodes soldered in then see if the switch pads activate using tweezers and a program like aquakeytest or switch hitter.

I guess I'm just stubborn when it comes to fixing things

[tp4tissue]

I'm very familiar with soldering, just not too familiar with the whole jumper wire thing that people do when they burn traces and the like, which is kind of what I'm under the assumption I need to do here if I wanted to get this PCB working.

After examining the board it looks like the diodes are definitely soldered in place save for two that have been twisted sideways. It might be the fact that the switches aren't seated fully into the plate, too - all in all I'm probably just going to desolder the Zealios as it appears all but one are functional.

try sanding the pcb then.. expose some copper..

[xtrafrood]

I'm very familiar with soldering, just not too familiar with the whole jumper wire thing that people do when they burn traces and the like, which is kind of what I'm under the assumption I need to do here if I wanted to get this PCB working.

After examining the board it looks like the diodes are definitely soldered in place save for two that have been twisted sideways. It might be the fact that the switches aren't seated fully into the plate, too - all in all I'm probably just going to desolder the Zealios as it appears all but one are functional.

try sanding the pcb then.. expose some copper..

lol don't listen to TP!

[suicidal_orange]

Sanding is an option but if you can see enough of the trace to do that you can probably work out where it goes and just solder to that pin or diode instead.

I too don't like to see things which are fixable get condemned so desolder those switches and take a pic so the damage can be assessed

[xtrafrood]

Sanding is an option but if you can see enough of the trace to do that you can probably work out where it goes and just solder to that pin or diode instead.

I too don't like to see things which are fixable get condemned so desolder those switches and take a pic so the damage can be assessed

Oh whoops, I learned something new today I thought TP was kidding around

[muon]

Yeah, just waiting on a better desoldering iron to come in Definitely not doing this with a pump and wick.

[xtrafrood]

Yeah, just waiting on a better desoldering iron to come in Definitely not doing this with a pump and wick.

You'll have to tools needed to desolder switches again should you decide that you want to try a different switch in the future

[tp4tissue]

Sanding is an option but if you can see enough of the trace to do that you can probably work out where it goes and just solder to that pin or diode instead.

I too don't like to see things which are fixable get condemned so desolder those switches and take a pic so the damage can be assessed

Why couldn't you sand it even if you can't see the trace through the lacquer..

[suicidal_orange]

Sanding is an option but if you can see enough of the trace to do that you can probably work out where it goes and just solder to that pin or diode instead.

I too don't like to see things which are fixable get condemned so desolder those switches and take a pic so the damage can be assessed

Why couldn't you sand it even if you can't see the trace through the lacquer..

Show Image

If the lacquer is already gone you wouldn't need to sand it :))

I meant if you can only see 2mm of trace going to a via that's probably beacuse there are other traces nearby and sanding would probaby uncover them too, then it's easy to make a short.  Traces aren't meant to be soldered so reheating to clean the short could cause more damage...

It can be done but I don't think it's the first choice for newbie solderers when 95% of the time the trace is going to a nearby diode or switch with exposed pads to solder to.

I've only seen one guy break the link back to the controller and he got lucky - it connected to one of the pins on the corner of the chip so he jumpered to that :eek: