High precision soldering of through hole components

I have a through hole component with many leads spaced closely together, see picture:

I'm looking to unsolder it from the PCB and then solder it back again. Unfortunately, the leads are spaced so closely and the beads of solder are so tiny, that I'm afraid I wouldn't be able to replicate this detailed work with my soldering iron.

What technique was used by the manufacturer of this board to achieve such high precision in soldering this component? What advice do you have for replicating this work at home while achieve the same quality result? I'm open to buying additional equipment if necessary.

• Were those two pins bent like that when it came from the factory? That's a sign of hand soldering. Aug 27 '14 at 16:04
• This is one of the very few instances where a conical soldering tip is called for. Aug 27 '14 at 16:04
• ...or a very small chisel tip... Aug 27 '14 at 16:09
• You are counting on removing the circuit board from that housing, right? That'll make your job far easier. Aug 27 '14 at 16:10
• @ThePhonton Yes, those two pins were bent like that from the factory. Aug 27 '14 at 17:12

That is not tiny, and not even close to close (pun intended).

I'd say the spacing between any two leads is abou 1mm, so you can use your soldering iron if you can buy a thinner tip. Thin solder can help a lot too, a bit of flux would be a great help but a waste for this kind of work in my opinion.

With a steady hand and less than 10$of additional equipment (tip+solder) you can make a job that will look (and be) much, much better than it is now. Desoldering the connector will be much more trouble. These are 13 pins, you will need to remove some of the solder using a copper desoldering wick braid cable or a small desoldering suction spring pump, then carefully pull out the component as evenly as possible, probably pulling out one side of some half mm, then the other side of a bit more, and so on. As suggested that looks hand soldered because of the bent tips, through hole components are normally soldered with wave soldering anyway. • Desoldering stuff like this is surprisingly difficult. You might destroy both the part and the board in the process, especially if you don't have patience. If I were doing it, I'd try to get a replacement part, then cut the original off with dikes, then remove one pin at a time. Quickest way to do this, and won't hurt the board Aug 27 '14 at 21:02 • I'd add that often the plastic casing of the connector can be safely removed because the pins are just slot in. Aug 27 '14 at 21:04 This is very simple to solder with a small tip. I use one like this: "0.031" OD x 0.75" L (0.79mm x 19mm)" conical tip. I think you'll have considerably more trouble de-soldering the part without ruining the board. Sometimes it's easier to destroy the part (cut it apart) then individually remove the pins from the board. Even with an expensive ($1K+) desoldering station (a carbon vane pump sucks the solder out leaving the plated through hole mostly empty) it's sometimes not that easy to do without damaging the board. If you have to make do with a hand solder sucker and wick it won't be easy.

• Dang, now it's about whose tip is smaller :^) Aug 27 '14 at 19:08
• Small tips don't transfer heat well. Aug 28 '14 at 1:56
• @ErikFriesen Sure, that's why there are bigger ones for bigger jobs. Snap on the one that suits your situation, and have at it. Aug 28 '14 at 1:59
• I have tried both styles. I prefer soldering .4mm pitch smt pins with a chisel tip and solder wick. Aug 28 '14 at 11:38
• Anything tighter than about 0.5mm and you may as well blob solder over a bunch of pins and wick it off with most irons. For serious use, I have one of these German Weller units: apexhandtools.com/brands/CF_Files/… but I thought that was bit much for the OP. No problem with heat. Still not quite as good as a Metcal. Aug 28 '14 at 12:55

This is not very high precision soldering. It may be either hand or wave soldered.

No equipment is necessary. With proper soldering iron and generous amount of flux, you can make it much nicer than it is now.

Cover a pad by blob of flux, then heat it with soldering iron touching both the pad and pin, then start pushing in solder wire (use very thin about $0.5\, \mathrm{mm}$) until a fillet forms. If you end up with too much solder, drag it to another pad or suck it away with solder wick.

You should be able to do solder work like that with a smaller tip like this one: http://www.gotopac.com/product_p/t15-bll-hak.htm. But I would make sure that you find one that is compatible with your soldering iron.

To remove the piece it will be tough, but very possible with a desolder braid like this one: http://www.gotopac.com/Easy_Braid_LF_A_100_p/lf-a-100.htm. If you have a very cheap solder station you may want to look into a rework station of some kind. That may help you out too.

Hope that helps.