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geekhack Community => Keyboards => Topic started by: infame on Mon, 13 July 2015, 13:16:35

Title: Quickfire TK diode soldering
Post by: infame on Mon, 13 July 2015, 13:16:35
Hello everyone,

I'm having some trouble trying to fix my CM Quickfire TK. Two keys stopped working, the left shift and the number nine in the upper roll. After checking some tutorials on how to solder pcb keyboards I decided to try to repair it myself. When opened, I noticed that the smd diode from the shift key had fallen and the one from the nine key cracked in the middle. Bought some diodes and soldered than right in place, however none of the keys worked. Thing is, when I removed the cracked diode, I saw a tiny squared piece of what seems to be a cooper pad/sheet under the spot the diode end is soldered, however I was not able to recover it since it came out along. Now it is just a white spot and the solder does not seem to bind well on it. (image below)

Wondering if anyone know how to fix it, since my experience on fixing boards is pretty much it.  Any advice would be highly appreciated.

Image:
(https://lh4.googleusercontent.com/9ts03sGnaKzpaVyVi9Lollfso0_S1_lcd6RjKiRLXpGcaVc_cDksei_NHBZQpvaOHbEFWVuvANhJETc=w1342-h547-rw)
Title: Re: Quickfire TK diode soldering
Post by: Alpsie on Mon, 13 July 2015, 14:54:18
Could you possibly add a picture of it?
Will make it  abit easier for us to suggest a fix.
Title: Re: Quickfire TK diode soldering
Post by: Tactile on Mon, 13 July 2015, 14:54:20
You don't solder to the circuit board. You solder to the copper traces on the circuit board. If the copper trace has lifted & been torn off, you'll need to solder to that trace further back where it is still sound. This might mean, if the distance is too great, soldering a short length of wire from the copper trace to the diode.
Title: Re: Quickfire TK diode soldering
Post by: infame on Wed, 15 July 2015, 08:06:32
Could you possibly add a picture of it?
Will make it  abit easier for us to suggest a fix.

I was finally able to post a picture.   
Title: Re: Quickfire TK diode soldering
Post by: infame on Wed, 15 July 2015, 08:08:58
You don't solder to the circuit board. You solder to the copper traces on the circuit board. If the copper trace has lifted & been torn off, you'll need to solder to that trace further back where it is still sound. This might mean, if the distance is too great, soldering a short length of wire from the copper trace to the diode.

Ok I see. Do I have to scratch the green surface to reach the cooper trace?   
Title: Re: Quickfire TK diode soldering
Post by: Tactile on Wed, 15 July 2015, 18:49:42
You can only solder to bare copper. If it's coated you'll need to scrape or clean it to get to the bare copper. Be sure not to damage the copper trace while cleaning it.