Author Topic: Reworking the LED Matrix?  (Read 5244 times)

FourG

  • Newbie
  • *
  • Posts: 7
Reworking the LED Matrix?
« on: July 16, 2014, 02:25:50 pm »
So, I made a bit of a fubar and soldered the LED matrix in backwards (black numbers towards the capacitors, rather than the edge of the board).  Tried some de-solder wick but can't seem to get the lead-free solder to wick out.  Anyone have any luck re-working a component on this board that might have a suggestion?  I don't have a desolder pump handy, unfortunately...

defragster

  • Sr. Member
  • ****
  • Posts: 467
Re: Reworking the LED Matrix?
« Reply #1 on: July 16, 2014, 04:32:14 pm »
Ouch.  I put my Pro headers on the wrong side - and even with a solder sucker I gave up getting a pin clean.  I cut the headers to expose the pins and the removed them one by one.  Even then with the solder sucker the holes got smaller - and wanted to bridge internally with solder I needed to suck out.

Worst case - dismember the matrix - and get a replacement LED module and a solder sucker to get the board back.

Klinkbot

  • Newbie
  • *
  • Posts: 2
Re: Reworking the LED Matrix?
« Reply #2 on: July 16, 2014, 05:02:23 pm »
Have you tried the "whack" method?  Get the solder hot and whack the board against a hard surface while holding it by the edge.  Not elegant and a bit messy but you'd suprized how mush solder comes out.

defragster

  • Sr. Member
  • ****
  • Posts: 467
Re: Reworking the LED Matrix?
« Reply #3 on: July 16, 2014, 07:13:26 pm »
I do recall seeing that https://www.sparkfun.com/news/802 and might be worth a try. 

But this sample shows one pin at a time on a header that was cut apart. 
« Last Edit: July 16, 2014, 07:15:30 pm by defragster »

gogol

  • Sr. Member
  • ****
  • Posts: 398
Re: Reworking the LED Matrix?
« Reply #4 on: July 17, 2014, 12:24:49 am »
Work pin for pin. Start in one corner, next pin is the diagonal opposite pin. (That is, to get head spreaded).

Like:


01-03-05-07-09-11-13-15
|                                      |
|                                      |
16-14-12-10-08-06-04-02


Put MORE SOLDER on the pin.
Use thick solder wick, wet by flux.
Put enough flux on the big solder blob.

That works for me in most cases.  You need (especially with lead free solder) an certain amount of solder to start the flow and spread the heat. If its to less solder, there is no way for the heat, to reach all surfaces, and the surface tension is holding the solder back and is still stronger than the capillary suction of the solder wick!

It sounds weird, but that is physics!

Let the board cool down every 4 or 6 pins.

digistump

  • Administrator
  • Hero Member
  • *****
  • Posts: 1465
Re: Reworking the LED Matrix?
« Reply #5 on: July 17, 2014, 05:12:50 pm »
You can email us support@digistump.com and we'll send you a new board and LED matrix we have a few extras