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I was going to suggest this too. Simply removing the part with
cutters, Dremel, etc can save a ton of stress on nearby components
and just leave a simple solder-sucking job to prep the area.<br>
<br>
Reminds me of four and a half eons ago when a minicomputer at my
school died and the service tech used (by today's standards
omniscient) diagnostics and his equipment to identify the specific
MSI logic component, snipped the tops of the DIP's leads, slurped
the ends and solder out, and soldered a new chip in. The computer
was running again about a half hour after he walked in the door.<br>
-Pete<br>
<br>
<br>
<div class="moz-cite-prefix">On 06/22/2016 11:35 AM, Robert
Gasiorowski via TriEmbed wrote:<br>
</div>
<blockquote
cite="mid:CAEU50hUR8vv7QUmcZfimdvUP7-crszdNUkkTpmKdahkU0hPeJA@mail.gmail.com"
type="cite">
<div dir="ltr">Hot air is the best, but it's not always possible
to use it.
<div>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.</div>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Wed, Jun 22, 2016 at 11:13 AM, Brian
via TriEmbed <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:triembed@triembed.org" target="_blank">triembed@triembed.org</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">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).<br>
<br>
Patience.<br>
<br>
-B<span class=""><br>
<br>
On 06/22/2016 08:59 AM, Adam Haile via TriEmbed wrote:<br>
</span>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex"><span
class="">
Also, what temp is your iron set to? Realizing that the
ChipQuik only<br>
helps in removal, but since those LEDs are designed to
be reflowed, they<br>
should certainly survive solder melting temp. One thing
that might cause<br>
an issue is using lead-free solder, especially of a
cheaper alloy which<br>
has a much higher temp. If you are using lead-free, try
leaded and keep<br>
the iron <= 600.<br>
<br>
On Wed, Jun 22, 2016 at 8:43 AM, Alex Davis via TriEmbed<br>
</span>
<div>
<div class="h5">
<<a moz-do-not-send="true"
href="mailto:triembed@triembed.org" target="_blank">triembed@triembed.org</a>
<mailto:<a moz-do-not-send="true"
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wrote:<br>
<br>
Anyone have any success with unsoldering APA102
LEDs without ruining<br>
them? It seems they are made of really shitty
thermoplastic which melts<br>
at about the melting point of the solder. I had
one go bad in my 44x8<br>
matrix, and I got it off by using a broad tip to
reflow one side at a<br>
time while lifting with tweezers. I'd say the
package has the thermal<br>
resistance of the sort of plastic cheap header
strips are made of. It<br>
was a ruined plastic blob by time I got it off.<br>
<br>
As to the repair, I am thinking I will just cut an
LED off a spare strip<br>
and solder it down on top of the blank spot. It
won't look as nice but<br>
it seems like it will have the highest change of
success and of not<br>
ruining the mounting strip.<br>
<br>
BTW these APA102 have in and out for both data and
clock, and in my case<br>
an LED stopped outputting anything on data out,
causing the whole rest<br>
of the strip to die. Thankfully it was just one
unit, but it gives me<br>
pause to consider building anything large and
expensive out of these<br>
things. My setup was working fine before I peeled
off the backing tape<br>
and glued it on to the enclosure.<br>
<br>
Alex<br>
<br>
--<br>
"The theater of noise is proof of our potential."<br>
|\ | (¯ \/ |¯\ |V| |\ ¯|¯ |¯) | \/ | | | |¯\
(¯ /¯ /\ |V|<br>
|-||_ (_ /\ |_/ @| | |-| | | \ | /\ |^| | |_/ (_
. \_ \/ | |<br>
<br>
You won't find me on Facebook.<br>
<br>
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