desoldering and re-soldering the mime IC - Page 1
Forum section: electronics / beginners

author: Adrian_Arg.
author_rank: Frequent Contributor
timestamp: December 17, 2020, 02:53:08 am
content: Hello, I have to remove a 74hc595 Smd, which I think is the cause of a failure, since I have a replacement, I use a yihua 952d station, the question is in case it is not the 74hc595, I can use this new item or the desoldering iron of heat I ruin it, it is my doubt.in spanishHola, tengo que retirar un 74hc595 Smd, que creo que es el causante de una falla, ya que tengo un reemplazo, uso una estacion yihua 952d , la duda es en caso de que no sea el 74hc595, podre usar este nuevamento o el desoldador de calor lo arruino, es mi duda.

author: Zero999
author_rank: Super Contributor
timestamp: December 17, 2020, 09:20:41 am
content: What makes you think it's faulty?Just cut the legs with some side cutters of a very sharp blade, so the body comes off. The legs can then easilly be desoldered.

author: HB9EVI
author_rank: Frequent Contributor
timestamp: December 17, 2020, 03:49:38 pm
content: use the hot air; I used to remove ICs the ways Zero999 describes, till one day I tore off a pad from the pcb while cutting the pin of the IC.think about a BGA chip, which has to be heated entirely to solder; if you have a matching nozzle for the IC's footprint, there is no danger to burn the chip

author: CharlotteSwiss
author_rank: Frequent Contributor
timestamp: December 17, 2020, 04:34:18 pm
content: my experience with smd is poor; but sometimes I do tests on old cards; not having a desoldering station, I use a hot air gun, but as you know it has large nozzles; unsolder unsolder, but I believe it can damage chips; perhaps a hot air station, unlike the gun, has a flow of air with less flow?...With the gun the smd fly meters away when they unsolder ..I am almost tempted to take a small hot air station (no soldering iron).I imagine that, for example, the special nozzles for square integrated, shoot air only on the pins and not on the body of the IC

author: Adrian_Arg.
author_rank: Frequent Contributor
timestamp: December 17, 2020, 05:12:13 pm
content: They lent me a yihua 952d, and I wanted to take advantage of the desoldering of some components, but if it damages them it is wasting time, that's why I asked.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: December 17, 2020, 05:34:06 pm
content: 72HC595 cost 20ct the PCB is much more expensive and so it your time.Some people cut the legs, but if you do this wrong this can result in high stress on the pad and rip it off.Other people use hot air, but PCB's go soft at such temperatures, and it's easy to rip of pads that way.I would prefer the hot air method. If you're inexperienced, start with watching some youtube vids and use aluminium foil or high teperature ape to shield the rest from getting too hot. It's also a good idea to get some old PCB's from somewhere to practice on.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: December 17, 2020, 05:49:30 pm
content: I am an animal. If there's space, I use two irons with something like that Hakko type K tip and approach each side of the chip, and overload the pins with solder. And BLOP! the thing comes off. No ChipQuick, no hot air... A bit of a mess though.I know, it's not an IPC-approved NASA-level space-rated approach. If I did that at SpaceX, Elon would personally break my soldering irons in two in front of the company and fire me. Louis Rossmann would make a two and a half hour rant against it.But it works...(Once we removed a QFP that way, two people, four irons, BLAP! it's off. Even a QFN came right off, just needed a bit more heat. Any reasonable PCB material these days can easily withstand a few seconds of that kind of heat)

author: Electro Fan
author_rank: Super Contributor
timestamp: December 17, 2020, 09:29:44 pm
content: Quote from: Alex Eisenhut on December 17, 2020, 05:49:30 pm