[TriEmbed] APA102 unsoldering

[Robert Gasiorowski]

Hot air is the best, but it's not always possible to use it.
When I need to remove SMD part and cannot use hot air, I crush/cut it with
pliers and unsolder each lead separately. This assures least heat stress on
pads.

On Wed, Jun 22, 2016 at 11:13 AM, Brian via TriEmbed <triembed at triembed.org>
wrote:

> Seconded.  Temperature and time is everything.  Not too hot and not too
> fast.  The best way to desolder SMT devices is to heat everything, and do
> it gradually.  If you have it available, use hot air and don't go above 280
> C.  It will take a fairly long time for the solder to melt, but the solder
> also has the highest thermal mass; that is, the plastic will heat up a lot
> faster than the metal.  If you're dumping heat in at 350 C, your plastic
> bits will hit 350 (and be a molten mess) way before the metal even gets
> near 280 (average reflow temp).
>
> Patience.
>
> -B
>
> On 06/22/2016 08:59 AM, Adam Haile via TriEmbed 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 <mailto: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
>>
>>     --
>>     "The theater of noise is proof of our potential."
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