This is a simple guide detailing how to repair damaged pads on a PCB.
Printed Circuit Boards (PCB) are made from layers of fibreglass and copper, glued together. Whilst the glues used are very heat resistant it is possible to overheat a PCB and damage it. Kitronik PCB designs use large tracks and pads to help make this a rare problem, the larger amount of copper helps to dissipate the heat.
If a PCB is overheated the most likely outcome is that the copper layer will de-laminate from the fibreglass board. This usually leads to broken joints and a non-working circuit.
Step 1: Tidy Up the Damaged Track 1:
Remove as little of the damage as possible to get back to a sound track. Cutting through the damaged tracks with a sharp knife will help to limit additional damage during removal.
Step 2: Tidy Up the Damaged Track 2:
Once the damaged track is removed it should look something like this.
Step 3: Exposing the Track:
Scrape a little of the solder resist off with a knife, sharp screwdriver or fine sandpaper. Ensure that the exposed track is clean and shiny. It is also a good idea to clean any residual burnt PCB material off, to allow the tape to stick well.
Step 4: Sticking Copper Tape Over the Exposed Track:
Stick on some of the copper tape. Overlap the existing track very slightly.
Step 5: Soldering the Copper Tape Joints:
Carefully solder the joint(s) where the repair has taken place. Most copper tape adhesive melts at soldering temperatures, so be quick and use as little heat as possible. When the tape cools the adhesive will usually remain sticky.
Step 6: Pierce to Make the Hole:
Rub over the pad area with a hard, rounded item, such as the none writing end of a Biro. This will push the copper tape down over the pad area. The pad hole will show through the tape, and can then be pierced with a component lead, paper-clip, or similar.
Step 7: Solder in Your Component:
The component can then be fitted and soldered in the normal manner. Keep the heat input from the soldering as brief as possible, as the adhesive and the additional joint attaching the new pad are sensitive.
Step 8: Carefully Trim the Repair:
The Copper tape can be cut to size with scissors, craft knife etc. Once a repair has been made it is also possible to trim the excess tape. If this is done exercise caution, as the repair is more fragile than the original PCB track, and may become unstuck again.
Step 9: Further Soldering Guides:
This guide is part of our soldering school, which is a collection of FREE basic guides for those new to soldering.Check them out!