[TriEmbed] APA102 unsoldering

[dan]

Chipquik and flux are my go-to for replacing those kind of LEDs, but i
usually regard the removed ones as trash for exactly the reasons you
mentioned. I'm trying to think of an alternative method to remove them
that, ignoring the LEDs, wouldn't wreck the pads. Hot air might be the best
bet, provided it doesn't mess up any nearby LEDs. A little bit of flux
would probably help.

-Sent from my phone
On Jun 22, 2016 9:18 AM, "Alex Davis via TriEmbed" <triembed at triembed.org>
wrote:

> Adam,
>
> ChipQuik works great, but I'm out if it at the moment. I've got a
> temperature-controlled soldering station, and I usually park the dial
> midway in the 'green' soldering zone so I'm not really sure what the
> temperature is. I never use lead-free solder, as I'm aware it needs more
> heat and is prone to reliability issues.
>
> I think the challenge with these is they're leadless and made of a plastic
> that's definitely less heat-resistant than the typical black resin. I'll
> play around with a test strip using a hot-air rework station, but I'd be
> reluctant to use that on my array since it's mounted to foamcore board
> which probably wouldn't hold up to any stray heat well.
>
> I'll probably try sticking a piece of strip in the reflow oven and see if
> I can get the LED to drop off during a cycle. I'd definitely like to keep a
> neat appearance on the array and mounting a replacement to the original
> pads would look best.
>
> Alex
>
>
> On Wed, Jun 22, 2016, at 08:59 AM, Adam Haile wrote:
>
> Also, what temp is your iron set to? Realizing that the ChipQuik only
> helps in removal, but since those LEDs are designed to be reflowed, they
> should certainly survive solder melting temp. One thing that might cause an
> issue is using lead-free solder, especially of a cheaper alloy which has a
> much higher temp. If you are using lead-free, try leaded and keep the iron
> <= 600.
>
> On Wed, Jun 22, 2016 at 8:43 AM, Alex Davis via TriEmbed <
> triembed at triembed.org> wrote:
>
> Anyone have any success with unsoldering APA102 LEDs without ruining
> them? It seems they are made of really shitty thermoplastic which melts
> at about the melting point of the solder. I had one go bad in my 44x8
> matrix, and I got it off by using a broad tip to reflow one side at a
> time while lifting with tweezers. I'd say the package has the thermal
> resistance of the sort of plastic cheap header strips are made of. It
> was a ruined plastic blob by time I got it off.
>
> As to the repair, I am thinking I will just cut an LED off a spare strip
> and solder it down on top of the blank spot. It won't look as nice but
> it seems like it will have the highest change of success and of not
> ruining the mounting strip.
>
> BTW these APA102 have in and out for both data and clock, and in my case
> an LED stopped outputting anything on data out, causing the whole rest
> of the strip to die. Thankfully it was just one unit, but it gives me
> pause to consider building anything large and expensive out of these
> things. My setup was working fine before I peeled off the backing tape
> and glued it on to the enclosure.
>
> Alex
>
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