PCB Repair Tips?

[FoxWolf1]

So, as of today, I have a new project.

My MicroConnectors D07-135TNG, in some ways, is quite a nice keyboard. The tactile non-clicky black ALPS are probably the highlight; they're definitely nicer than the green XM switches on the Ducky 1008XM I used to use, a bit heavier and less wobbly, with a nice meaty tactile point. It also has a true Mac layout, with Command in the correct place and a Mac-style numberpad (small +, so that the pad can have an = key), which I probably would have appreciated a bit more had I not acquired it a week before the abrupt and unexpected end of my 20+ years as a Mac owner. And, though the quality isn't terribly impressive, the price is very right: I picked it up here back in the spring, new-in-box (though it's quite old stock at this point), for all of $14.99 plus shipping.

But, here's the thing...for me to consider a keyboard "useable", it needs to be decent for both work and gaming. I multitask a lot, and will sometimes open up a game while thinking about work, so a keyboard that can only handle one or the other isn't much good to me. Now, the D07-135's switches are quite decent for gaming, but the keyboard itself isn't. You see, it's 2KRO...aggressively, brutally 2KRO. The kind of 2KRO where all 3-key combinations work just fine except for the ones you actually use, all of which fail. This won't do, especially since, with a Noppoo TANK as my main keyboard, I'm used to not even having to think about rollover (the TANK has true n-key rollover over USB).

Anyway, an idea occurred to me recently. My Ducky was an ALPS keyboard, and it had 6KRO (USB). Although it had its share of build quality issues (more on those in a second), it had some other advantages over the D07-135 as well: for instance, the plate on which the switches are mounted was made of metal, rather than low-grade plastic as on the D07. It had a rather more presentable appearance, too. So I decided that what I'd do is take the switches out of the D07-135, and out of the remains of the Ducky, swap the blacks into the Ducky, and in the process, get the Ducky back into working condition.

Here's the catch: when disassembling the Ducky and desoldering its switches, I finally figured out why it had started to malfunction. Turns out that the switches were fine, USB was fine, controller was fine...but the PCB itself was starting to come apart, the wear and tear of two months' use causing several of the pads to which the switches were soldered to start to detach from the traces, with one or two completely off. So, in order to recommission it, I'll have to piece it back together. I have both a gel pen and some conductive tape on the way, but does anyone have any keyboard PCB repair tips to share? Any would be appreciated. Thanks!

[RickyJ]

Post pics please!  There's a few of us here that do PCB work.

Very strange for pads to lift so soon on their own, though not impossible with a poorly made single-sided PCB.  I've had pads lift on single-sided PCB's before (not just keyboards), sometimes it's due to too much heat from the iron.  If the traces had broken away from the pads on their own though, that's a pretty bad sign for the rest of the board.

For multiple small traces, I use 30-AWG "wire wrap" wire and strip the ends with my exacto knife.  I use the same knife to strip the solder-mask off the end of the broken trace, and solder it in.

[FoxWolf1]

My attempts at keyboard photography, I fear, leave something to be desired...and by "leave something to be desired," I mean that I have yet to figure out how to produce anything at the detail scale other than an unrecognizeable greenish blur. Here it is, though. You can kind of see what used to be a pad...sort of. Some of the others that came off are significantly lighter in color; this may have been one that I killed rather than one that came off on its own. The end result seems pretty much the same, though.

]

But yes, the PCB was coming apart before I did any desoldering, though additional pads came off during the desoldering process (I'll take responsibility for those...tremors in both hands and very little experience mean I'm not exactly a soldering ace). If you want to try and imagine it: basically, where the traces on the PCB used to lead to silvery, circular pads to which the switches were soldered, there are now brownish circles to which solder, despite my best efforts, will not adhere. In cases where this happened before the keyboard's disassembly, the result was key-death, which is why I stopped using the Ducky in the first place. In a couple of cases, small lengths of trace also came off together with the pad.

[Soarer]

Sounds like the switches weren't fully up against the PCB when the board was soldered, leaving the solder joint to take the force of each keypress. That's pretty shoddy

I'm not sure I would try to repair the traces as such, instead just solder back in what you can and then use thin wire to jump from switch pin to switch pin for the rest. For all switches, hold the switch firmly onto the pcb while soldering. Even where pads have lifted (but not broken) they can still be used to solder and hold the switch in - just try and push the pad up against the pcb with the iron (the idea being that they are still fine for preventing the switch pulled upwards). For switches where both pads have broken, you can hook some wire round the pin and do the same, pushing it tight up to the pcb while soldering. That should avoid any 'loose' switches which would cause further damage (or feel different in use).

[FoxWolf1]

Sounds like the switches weren't fully up against the PCB when the board was soldered, leaving the solder joint to take the force of each keypress. That's pretty shoddy

I'm not sure I would try to repair the traces as such, instead just solder back in what you can and then use thin wire to jump from switch pin to switch pin for the rest. For all switches, hold the switch firmly onto the pcb while soldering. Even where pads have lifted (but not broken) they can still be used to solder and hold the switch in - just try and push the pad up against the pcb with the iron (the idea being that they are still fine for preventing the switch pulled upwards). For switches where both pads have broken, you can hook some wire round the pin and do the same, pushing it tight up to the pcb while soldering. That should avoid any 'loose' switches which would cause further damage (or feel different in use).

Sounds like good advice; thanks!