We assume the following:
- You have a decent solder iron that is powerful enough to handle largish solder joints to ground planes that soak up lots of heat, but will not overheat when idle. Ideally speaking the solder iron should have interchangeable tips, one about 1/16" to 1/8" wide, and another at most 1/32".
- You master the basics of soldering technique.
You will need:
- a de-soldering pump a.k.a. solder-sucker
- some desoldering braid
- some 60/40 solder - this type of solder contains lead and is banned from production but melts at lower temperatures than the tin/silver, lead free solder used in production and is easier to use for rework or repair. 0.5mm dia solder wire is optimal, 0.7 is usable, anything bigger is too big.
- small pliers, a small flat blade screwdriver to abuse as a prying tool.
- some isopropyl alcohol and a clean brush
- a magnifier comes in handy.
The first issue is grounding. Modern micro-electronics are very sensitive to static discharge and leakage currents. Your soldering iron must be grounded, and your workpiece too, lest you risk converting your workpiece into a paperweight. Many temperature controlled irons have a grounding socket on the control unit, you can clip or tack solder a wire to the workpiece's ground plane and connect it to said socket. Ideally speaking you should ground yourself too, with a proper conductive wristband.
Now we can tackle the job proper.
- From the underside of the board, heat the 4 tabs of the connector's housing in turn one by one, enough to melt the solder around them, and remove the molten solder with the desoldering pump, ideally until you have removed most of the solder from the holes in the board.
- Remove the remaining solder from the tab holes with desoldering braid. Place the end of the braid over the tab hole, lined up along the edge of the tab, and heat both the tab and the braid with the tip of the iron. The solder remaining in the hole will wick into the braid as it melts. As the tip of the braid saturates with solder, cut it of and start over with the freshly cut end. Continue until all the solder is gone, the tab should be just about completely free and daylight should be visible around the tab.
- If the tabs have a little nick or bend (so the tab "clicks" into the hole) use the pliers to straighten it out, this makes it easier to remove any remaining solder.
- Once the tabs are completely free, try to very gently lift up the end of the connector opposite the contact pads, by a small fraction of an inch.
- Finally, cover the contact pads of the connector with a blob molten solder, and with some very gentle prying lift the connector from the board. Be very very careful, the solder on all pads must be fully molten but you must take care not to overheat the pads. If you lift one or more contact pads from the board, you're toast.
- Carefully remove most of the blob of solder from the contact pads with the desoldering pump, and any remaining excess with desoldering braid. Lay a fresh end of desoldering braid on the pads and heat the braid, not the pads, applying gentle pressure with the tip of the solder iron. Again, be careful not to overheat the pads!
- Clean the area with some isopropyl to remove residue, and inspect. Pads should be clean and intact.
- Fit the new connector on the board and see if it lines up correctly. Keep the contact pins perfectly lined up with their pads, and tack solder the 2 tabs closest to the edge of the board from the upper side while keeping the contact pins perfectly aligned on their pads. When you are satisfied the connector is indeed perfectly aligned, proceed to solder the tabs from the underside of the board.
- If you have an iron with interchangeable tips, now it's the time to fit the finest tip you have.
- Solder the contact pins to their pads, using the least amount of solder necessary to get a good joint. The cleanest way to do this is to place the tip of the iron on top of the lead with gentle downward pressure and feed the solder wire to where the lead and pad meet. Watch out for shorts.
- Clean with some isopropyl, and inspect for shorts and other irregularities with a magnifier.
- You're done! (phew!)
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