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geekhack Community => Keyboards => Topic started by: Beca on Wed, 19 March 2014, 21:04:17

Title: Switch suddenly became non-responsive. Is it because of a bad soldering job?
Post by: Beca on Wed, 19 March 2014, 21:04:17: 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:

(http://i.imgur.com/PILnYxF.jpg)

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?
Title: Re: Switch suddenly became non-responsive. Is it because of a bad soldering job?
Post by: laffindude on Wed, 19 March 2014, 21:22:44: 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.
Title: Re: Switch suddenly became non-responsive. Is it because of a bad soldering job?
Post by: Beca on Wed, 19 March 2014, 22:02:48: Quote from: laffindude on Wed, 19 March 2014, 21:22:44
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?
Title: Re: Switch suddenly became non-responsive. Is it because of a bad soldering job?
Post by: laffindude on Wed, 19 March 2014, 23:13:52: 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).
Title: Re: Switch suddenly became non-responsive. Is it because of a bad soldering job?
Post by: jacobolus on Thu, 20 March 2014, 01:10:01: 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.
Title: Re: Switch suddenly became non-responsive. Is it because of a bad soldering job?
Post by: False_Dmitry_II on Thu, 20 March 2014, 05:30:49: 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.
Title: Re: Switch suddenly became non-responsive. Is it because of a bad soldering job?
Post by: jacobolus on Thu, 20 March 2014, 05:59:18: Well yeah, that’s what I mean by “patch”.
Title: Re: Switch suddenly became non-responsive. Is it because of a bad soldering job?
Post by: Beca on Thu, 20 March 2014, 15:48:30: 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 :(
Title: Re: Switch suddenly became non-responsive. Is it because of a bad soldering job?
Post by: jacobolus on Thu, 20 March 2014, 15:58:18: 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)?
Title: Re: Switch suddenly became non-responsive. Is it because of a bad soldering job?
Post by: Beca on Thu, 20 March 2014, 16:05:23: Quote from: jacobolus on Thu, 20 March 2014, 15:58:18
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:
Title: Re: Switch suddenly became non-responsive. Is it because of a bad soldering job?
Post by: False_Dmitry_II on Thu, 20 March 2014, 16:24:05: Ah, I thought you meant to somehow repair the actual broken trace. Which sounds difficult to me.
Title: Re: Switch suddenly became non-responsive. Is it because of a bad soldering job?
Post by: tooki on Fri, 21 March 2014, 08:21:12: Quote from: False_Dmitry_II on Thu, 20 March 2014, 16:24:05
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.
Title: Re: Switch suddenly became non-responsive. Is it because of a bad soldering job?
Post by: Beca on Sun, 06 April 2014, 02:30:26: 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!

(http://i.imgur.com/L7WWAw4.jpg)
Title: Re: Switch suddenly became non-responsive. Is it because of a bad soldering job?
Post by: dorkvader on Sun, 06 April 2014, 02:40:57: 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.
Title: Re: Switch suddenly became non-responsive. Is it because of a bad soldering job?
Post by: Beca on Sun, 06 April 2014, 02:46:09: Quote from: dorkvader on Sun, 06 April 2014, 02:40:57
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?
Title: Re: Switch suddenly became non-responsive. Is it because of a bad soldering job?
Post by: blackbox on Sun, 06 April 2014, 05:01:31: Quote from: Beca on Sun, 06 April 2014, 02:46:09
Quote from: dorkvader on Sun, 06 April 2014, 02:40:57
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.
Title: Re: Switch suddenly became non-responsive. Is it because of a bad soldering job?
Post by: laffindude on Mon, 07 April 2014, 04:06:37: Quote from: Beca on Sun, 06 April 2014, 02:30:26
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
(http://i.imgur.com/L7WWAw4.jpg)

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.