Page 140 - CITS - Electronic Mechanic - TT - 2024

ELECTRONICS MECHANIC - CITS

Component Replacement:
New components or replacement parts are installed in place of the defective ones. Careful attention is paid to
component orientation, alignment, and soldering.

Soldering and Reflow:
Soldering techniques such as hand soldering or reflow soldering are used to secure the replacement components
to the PCB.

Inspection and Testing:
The reworked or repaired assembly undergoes thorough inspection and testing to ensure that the defect has been
successfully rectified and that the product meets quality standards.

Tools and Equipment:
Soldering Irons and Stations
Desoldering Tools (Solder Suckers, Desoldering Pumps)
Hot Air Rework Stations
Soldering Stations with SMD Rework Attachments

Microscopes and Magnifiers
PCB Rework Kits and Tools
Importance of Rework and Repair:
Cost Savings: Rework and repair can salvage defective components or assemblies, reducing the need for
scrapping and re-manufacturing.
Quality Assurance: Ensures that electronic products meet quality standards and customer requirements before
being released to the market.
Customer Satisfaction: Minimizes the likelihood of faulty products reaching customers, enhancing brand
reputation and customer satisfaction.

Repair Of Damaged Track:
Repairing a damaged track on a printed circuit board (PCB) involves restoring the electrical connection between
two points on the board where the conductive copper trace has been damaged or broken. Here’s a general guide
on how to repair a damaged track on a PCB:
1 Assessment: First, identify the damaged track and assess the extent of the damage. Determine whether the
track is partially or completely severed and whether nearby components have been affected.
2 Isolation: If the damaged track is 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 track 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 section of the track by carefully scraping away the solder mask or protective
coating covering the copper trace using a sharp hobby knife or fiberglass scratch pen. Be cautious not to
damage adjacent traces or components.

5 Repair Method: - Jumper Wire: The simplest method is to use a thin insulated jumper wire to bridge the gap
in the track. Cut a piece of wire to the appropriate length, strip the insulation from both ends, and solder it onto
the remaining sections of the track to create a continuous electrical connection. - Conductive Ink or Paint:
Alternatively, conductive ink or paint can be used to bridge the gap. Apply the conductive material over the
damaged section using a fine-tip applicator or brush, ensuring that it forms a continuous connection between
the two points. Allow the ink or paint to dry thoroughly before testing the repair. – Copper Foil: In cases where
the damaged track is wide or requires additional strength, a small piece of copper foil can be used to patch the
area. Cut a piece of copper foil to fit over the damaged section, apply flux to the damaged area, place the foil
over the gap, and solder it into place.

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