Re-instating header pins on a PCB
One trick here is to clamp the board vertically while working on it.
The solder pads need to be cleaned out to expose the thru-holes.
From one side of the board, apply heat to one of the solder pads using a fine soldering iron bit.
Simultaneously, and working from the other side of the PCB, use a desoldering pump (solder sucker) to remove the molten solder from the hole.
Repeat for each thru-hole.
Sometimes one or more of the holes isn't properly drilled out.
If so, use a 1mm HSS drill bit and twist it manually between fingers
Ensure all the holes are clean and free from grease and PCB coating materials.
Install the header pins and solder in place
Job done!
Attached are some photos showing the reinstatement of header pins for JTAG/UART on the PCB of a Huawei HG612.
