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geekhack Projects => Making Stuff Together! => Topic started by: Snips on Wed, 09 November 2016, 12:01:56

Title: Repairing Das PCB for a friend.
Post by: Snips on Wed, 09 November 2016, 12:01:56: This is my first actual post here! I hate that it has to be a post asking for free help, but I hope to become a more active member.

So, to give a bit of context to this (for those that care, anyway,) This was my second mechanical keyboard I ever owned, and one of the originals that I tried modding. Back during this time, I didn't have the proper equipment (I had the proper soldering iron, just not the proper solder or the correct tools to de-solder,) to be working on PCBs with, but unfortunately my stubbornness got the best of me after reading online about some methods to desolder without having a sucker, wick, or copper wire with flux. What resulted was me frying the board in a couple of places, you get the drift. I've since gotten the right tools for the job and gotten a lot more practice under my belt, but I'm still learning.

(http://i.imgur.com/NP14LbG.jpg)

(http://i.imgur.com/U5Yo4km.jpg)

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

So, after having this PCB sat up on my shelf for a couple of months, I've decided to take a crack at repairing it in hopes of hooking a good friend of mine up with their first mechanical keyboard. I presume I need to jump trace for the two keys I provided a close up of, but I'm a bit stumped on how to do so. I don't have any kind of Ohm Meter.
Title: Re: Repairing Das PCB for a friend.
Post by: Moistgun on Wed, 09 November 2016, 12:05:21: Good luck poor soul.

this is pretty bad man.
Title: Re: Repairing Das PCB for a friend.
Post by: Snips on Wed, 09 November 2016, 12:07:18: Yeah.. It's pretty bad, but I'm pretty determined to get it to work. I have the time and the desire to get it working, assuming it can be fixed.
Title: Re: Repairing Das PCB for a friend.
Post by: Tactile on Wed, 09 November 2016, 12:30:15: It's fixable. Find the traces, scrape the varnish off, and tack solder wires to the trace & the switch contacts. I have some of that Radio shack paste flux. It's not bad but my favorite is MG Chemicals 835 liquid flux.

Anyway, with the care & patience of a model builder you can repair this. It won't win any awards when you're finished but the keyboard will work.
Title: Re: Repairing Das PCB for a friend.
Post by: suicidal_orange on Wed, 09 November 2016, 12:35:03: Just the two switches damaged with no desoldering tools? Very impressive, unless they were the first two you tried before giving up :))

Try this (you can go in a straight line across the bottom three pins, I've just traced the paths as on the PCB)

(http://i.imgur.com/90v1Wcu.jpg)
Title: Re: Repairing Das PCB for a friend.
Post by: tp4tissue on Wed, 09 November 2016, 13:30:12: as long as you didn't crack the pcb anywhere..

following up on traces is tedious, but nothing's really broken.
Title: Re: Repairing Das PCB for a friend.
Post by: Snips on Wed, 09 November 2016, 14:25:17: Quote from: suicidal_orange on Wed, 09 November 2016, 12:35:03
Just the two switches damaged with no desoldering tools? Very impressive, unless they were the first two you tried before giving up :))

Try this (you can go in a straight line across the bottom three pins, I've just traced the paths as on the PCB)

Show Image
(http://i.imgur.com/90v1Wcu.jpg)

This worked for those keys! I tried using what method you seemingly used for following the trace in this photo for another key that no longer works (the spacebar key, to be exact,) and it didn't work. Could you give me some pointers on how to follow the trace like you did in that picture?

Thanks to everyone for being so helpful so far, you guys are a lot more friendlier towards someone learning than people on the mechanicalkeyboards subreddit were.
Title: Re: Repairing Das PCB for a friend.
Post by: suicidal_orange on Wed, 09 November 2016, 16:39:52: There are no tricks, just patience and a paint program! One leg will always connect to other switches, the other to a diode. Then the other side of the diode connects to other diodes. A break anywhere between the controller and a switch or diode can take out huge chunks of keys so if you think what you've done is right it may well be, but there's more...

Not sure how I missed the bottom row but for starters it looks like there's a break in the trace below two switches to the left of the spacebar diode, so you'll need a long jumper going that way if you haven't got one yet. I'm on mobile getting an early night but will post a pic in the morning if you're still stuck :thumb:
Title: Re: Repairing Das PCB for a friend.
Post by: Snips on Wed, 09 November 2016, 18:05:36: Quote from: suicidal_orange on Wed, 09 November 2016, 16:39:52
There are no tricks, just patience and a paint program! One leg will always connect to other switches, the other to a diode. Then the other side of the diode connects to other diodes. A break anywhere between the controller and a switch or diode can take out huge chunks of keys so if you think what you've done is right it may well be, but there's more...

Not sure how I missed the bottom row but for starters it looks like there's a break in the trace below two switches to the left of the spacebar diode, so you'll need a long jumper going that way if you haven't got one yet. I'm on mobile getting an early night but will post a pic in the morning if you're still stuck :thumb:

Just spent the last couple of hours trying to figure out where exactly you meant. I presume the locations I tried were incorrect since this didn't work. So, for the time being, I'm going to get some shut eye myself. If you can post that reference image in the morning, that would really help out. Thank you so much for your help!
Title: Re: Repairing Das PCB for a friend.
Post by: suicidal_orange on Thu, 10 November 2016, 03:04:50: Probably not wrong, you just need more fixes. I expect you connected the spacebar to the diode (connection through the diode dotted as an example what's going on) but the signal would be cut where there's a break in the trace running along the bottom so it didn't work. Can't see where that trace goes, just hoping it's not straight to the pin on an SMD controller chip...

There are three red circles (:))) - one I can't see what's going on for solder, one chance of slicing through all the traces and a burnt switch out of focus - if you still have problems feel free to post pics of these areas, with the solder removed on the middle one.

(http://i.imgur.com/M7D1j9G.jpg)
Title: Re: Repairing Das PCB for a friend.
Post by: Snips on Thu, 10 November 2016, 21:50:33: Quote from: suicidal_orange on Thu, 10 November 2016, 03:04:50
Probably not wrong, you just need more fixes. I expect you connected the spacebar to the diode (connection through the diode dotted as an example what's going on) but the signal would be cut where there's a break in the trace running along the bottom so it didn't work. Can't see where that trace goes, just hoping it's not straight to the pin on an SMD controller chip...

There are three red circles (:))) - one I can't see what's going on for solder, one chance of slicing through all the traces and a burnt switch out of focus - if you still have problems feel free to post pics of these areas, with the solder removed on the middle one.

Show Image
(http://i.imgur.com/M7D1j9G.jpg)

Bit of an update: I managed to get most of the keys working, now. I had to jump some other keys, but they're working! The ones that you circled in red were in rough shape, but most of them didn't need to be jumped. And it seemed that trace you circled in red was just some dog hair, I just checked the PCB and that thing isn't there anymore.

As I post this, I'm still trying to figure out how to fix the spacebar, as it's the only necessary key that is no longer functioning at this point.

Edit: I have managed to successfully jump the trace for the spacebar! I'm now working on finishing the rest of the keys. I will update this post if I need further help. If not, I will request that the thread be closed.

Edit 2: I have successfully jumped all of the traces and got it fixed. Thank you to everyone that helped me in completing my first actual trace repair. Mods, you can lock this thread now.