Chosen Solution
Hello I’ve tried to replace the chip IC Tristar, because my iPhone is not charging, I removed the chip and replaced for a new one, but the iPhone still not turning on. On these processes I used heat, flux, and the replacement was ok. However, I didn´t removed the solder, from the previous chip from the logic board and when I removed, I saw that the 2 layers of solder (older chip and the new one), was too much. I buy solder wick, in order to remove the excess of solder (Brand: ProKit´s 1.5mm), as can be seen on the link. But the solder wick is not, catching with the solder, at least is not so easily (sometimes it grabs a little of solder). When I used, the wick, I tried, with and without flux, but the problem stills. Can someone give me some advices/tips, of what am I doing wrong, or some missing step, that I should be doing? Another questions is about the, proper temperature that I should be using, and the time that I can have the soldering iron above the board, without damaging it? Thanks in advance, for any help provided.
This is really about proper heat transfer. Obviously flux will help with the heat transfer but if the flux didn’t make much of a difference, it is either because your tip wasn’t hot enough or large enough. Personally, I set my iron or hot tweezers to 380C, unless I am working on flexes or other “soft” materials. The whole point of soldering is getting the solder/pads to the proper melting point of the solder (Leaded ~185, Lead-free ~217C). However, the size of the pads/components and the underlying pcb (i.e. a ground plane) can cause a huge variation in the amount of heat required to get it to the right temperature. Small tips transfer less heat and if you are working on ground plane pads, it will not be enough. So then you need a larger tip or pre-heat the logic board to ~125C. As for leaving the old solder behind, the best practice is to remove as much of it as possible but wicking is typically avoided as the pads are very delicate and can easily be removed by the wicking action. To do this, I suggest a concave tip, such as this one. It will literally suck up the solder from the pads. It won’t remove all of it but leave just enough behind. All of this to say that you really need to practice this “art” on dead or donor boards until you get the right feel for when things are done properly or not. It is also about not trying something new on something of value
