Page 141 - CITS - Electronic Mechanic - TT - 2024

ELECTRONICS MECHANIC - CITS

6 Inspection and Testing: Once the repair is complete, visually inspect the repaired track to ensure that it’s
properly connected and there are no solder bridges or other defects. Use a multimeter to check for continuity
between the repaired track and adjacent components or traces.

7 Protection: After verifying the repair, apply a new layer of solder mask or conformal coating over the repaired
area to protect it from moisture, oxidation, and mechanical damage. By following these steps carefully, you can
effectively repair a damaged track on a PCB and restore its functionality. However, it’s important to note that
PCB repair requires precision and skill, so if you’re not confident in your abilities, consider seeking assistance
from a professional or experienced hobbyist.
Repair Of Damaged Pad And Plated Through Hole
Repairing a damaged pad and plated through hole on a printed circuit board (PCB) can be more complex than
repairing a damaged track, but it’s certainly possible with the right tools and techniques. Here’s a step-by-step
guide on how to repair a damaged pad and plated through hole:
1 Assessment: Identify the damaged pad and plated through hole on the PCB. Determine the extent of the
damage and whether nearby components or traces have been affected.
2 Isolation: If the damaged pad and through hole are part of a larger circuit, isolate the damaged section by
cutting away any surrounding copper that may be causing short circuits or interference.
3 Cleaning: Clean the area around the damaged pad and through hole using isopropyl alcohol or a specialized
PCB cleaning solution to remove any dirt, flux residue, or contaminants that may interfere with the repair
process.
4 Exposure: Expose the damaged pad and through hole by carefully scraping away the solder mask or protective
coating covering the area using a sharp hobby knife or fiberglass scratch pen. Be cautious not to damage
adjacent traces or components.
5 Repair Method: Pad Repair: If the pad is partially damaged but still intact, you can reinforce it by applying a
small piece of copper foil or using conductive epoxy to build up the pad. Ensure that the pad is flat and level
before proceeding. - **Through Hole Repair**: If the plated through hole is damaged or completely missing,
you’ll need to create a new connection between the two sides of the PCB. This can be done by drilling out
the damaged hole to remove any remaining debris and then inserting a replacement wire or component lead
through the hole. Solder the wire or lead to the exposed copper on both sides of the PCB to create a new
through connection.
6 Inspection and Testing: Once the repair is complete, visually inspect the repaired pad and through hole to
ensure that they’re properly connected and there are no solder bridges or other defects. Use a multimeter to
check for continuity between the repaired pad and through hole and adjacent components or traces.
7 Protection: After verifying the repair, apply a new layer of solder mask or conformal coating over the repaired
area to protect it from moisture, oxidation, and mechanical damage.
8 Reassembly: If any components were removed during the repair process, reassemble the PCB and test it
to ensure that it functions as intended. Repairing a damaged pad and plated through hole on a PCB requires
careful attention to detail and precision soldering skills. If you’re not confident in your abilities, consider seeking
assistance from a professional or experienced hobbyist.
REPAIR OF SOLDER MASK:
Repairing solder mask on a printed circuit board (PCB) typically involves touching up areas where the solder
mask has been damaged or removed during the manufacturing process or subsequent rework. Here’s a step-by-
step guide on how to repair solder mask on a PCB:
1 Assessment: Inspect the PCB to identify areas where the solder mask is damaged, scratched, or missing.
Ensure that the underlying copper traces and components are not affected.
2 Cleaning: Clean the damaged area thoroughly using isopropyl alcohol or a specialized PCB cleaning solution
to remove any dirt, flux residue, or contaminants that may interfere with the repair process. Allow the area to
dry completely before proceeding.
3 Surface Preparation: If the damaged area is rough or uneven, gently sand it with fine-grit sandpaper to
smooth out the surface. Be careful not to damage any nearby components or traces.

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CITS : E & H - Electronics Mechanic - Lesson 73 - 76