Switch suddenly became non-responsive. Is it because of a bad soldering job?

[Beca]

This board was the first time I have ever soldered something. Every key worked perfectly fine (for about a month and a half  now) until a few days ago when the "W" key became unresponsive (first it didn't register a few strokes, now it doesn't work at all).

Here is the soldering joint for that key:



When I bought the board used, the join was already like this. I tried my best to work with it, and it was of no problem until now. I think I put too much solder on it as well.

Is it salvageable?

[laffindude]

A lot of the solder joints looks like it didn't wet.
Clean up the joint with solder braid. See what is under those blobs around the switches.

[Beca]

A lot of the solder joints looks like it didn't wet.
Clean up the joint with solder braid. See what is under those blobs around the switches.

Hm, what do you mean by wet? And I'll definitely get a soldering braid. Do you know what's causing it to suddenly not work?

[laffindude]

Consult google on wetting.

The switch in particular. It looks like solder didn't take on the switch pin. Can't really tell given potato picture. Dab some flux on it and just touch the iron on the pin.
Plug the keyboard in and bridge the 2 pins, see if it output anything.

Also, not sure if that gap between the switch pin pad and blob is intentional or mistake in layout (which they try to fix with a blob).

[jacobolus]

I’m not an expert by any means, but I’d try 2 things. First, as laffindude suggests, try plugging it in and bridging those pins and see what happens. Second, if you have an ohmmeter or continuity tester, try touching its test leads to the two pins and see if the switch itself is still working.

If the switch is busted, you can try to fix it or swap it out. If the solder joint isn’t very good, you can re-do it. If one of the traces is messed up, someone here can advise you about how to patch it up.

[False_Dmitry_II]

Why patch it? Just look at where it goes and then use a wire to go from one terminal to the same place the trace would have gone.

[jacobolus]

Well yeah, that’s what I mean by “patch”.

[Beca]

Next time I won't use a $4 soldering iron. Thanks for all the advice! Not sure if I want to deal with this; not enough time, experience, or money

[jacobolus]

Beca, do you have a multimeter?

Can you test (1) what happens if you plug the keyboard in and then bridge those two pins (e.g. by touching a piece of wire to both), and (2) whether the switch itself works (a continuity tester setting on the multimeter is the easiest way to test this)?

[Beca]

Beca, do you have a multimeter?

Can you test (1) what happens if you plug the keyboard in and then bridge those two pins (e.g. by touching a piece of wire to both), and (2) whether the switch itself works (a continuity tester setting on the multimeter is the easiest way to test this)?

I don't have one the only soldering equipment/accessories I got is a cheapo iron D:

[False_Dmitry_II]

Ah, I thought you meant to somehow repair the actual broken trace. Which sounds difficult to me.

[tooki]

Ah, I thought you meant to somehow repair the actual broken trace. Which sounds difficult to me.

It can be done, but to repair my el-crapo CMStorm, I used the wire bridge method described above. Repairing a trace without a patch wire seems like waaaay too much work and risk of damaging good traces, with no discernible advantage as far as I can tell.

[Beca]

I finally  opened up the keyboard today, and after using some wick to remove the solder, the pad was practically hanging off.


The gap in the joint on the right (look at extremely low definition picture below) caused the trace to be broken I guess? I didn't have any lead wire so I just threw on some solder to fill the gap and the key works now. The PCB is definitely going to the trash if I ever sell this board!

[dorkvader]

Yes, I think that break might be your problem.

Since there is solder on both sides, you can probably fix it by bridging the gab by putting a ton of solder on it, this is a trace repair.

I prefer to just "patch" it by replacing the trace with a bit of wire, which is what Jacobolos mentioned.

[Beca]

Yes, I think that break might be your problem.

Since there is solder on both sides, you can probably fix it by bridging the gab by putting a ton of solder on it, this is a trace repair.

I prefer to just "patch" it by replacing the trace with a bit of wire, which is what Jacobolos mentioned.

I did the option where I put a ton of solder on it, but I'm afraid it won't be durable. Should I still try to get the trace repaired by a wire?

[blackbox]

Yes, I think that break might be your problem.

Since there is solder on both sides, you can probably fix it by bridging the gab by putting a ton of solder on it, this is a trace repair.

I prefer to just "patch" it by replacing the trace with a bit of wire, which is what Jacobolos mentioned.

I did the option where I put a ton of solder on it, but I'm afraid it won't be durable. Should I still try to get the trace repaired by a wire?

If it works I think you should leave it. It shouldnt be any pressure applied to it.

[laffindude]

The gap in the joint on the right (look at extremely low definition picture below) caused the trace to be broken I guess? I didn't have any lead wire so I just threw on some solder to fill the gap and the key works now. The PCB is definitely going to the trash if I ever sell this board!

Show Image

That is semi what I thought before.
The blobular approach in fixing it works well enough. The biggest issue is that the adhesive is already destroyed by heat, evident by the detached pad. I am not sure it is a good idea to heat up the joint even more. I'd just keep using it and deal with the issue as it crops up.