Restoring Gold Edge Connectors

Sometimes, during the reflow of circuit board assembly, improper handling can cause gold edge connectors to be splattered with solder or solder paste. This type of solder contamination results in the buildup of oxidation on the solder. As a result, the electrical flow to the mating connector can become compromised, while at the same time, the irregular surface of the connector also adversely impacts the connection.

To effectively correct this issue, you need to clean all of the contamination off the assembly and restore the gold edge connectors. Note that because certain chemicals are used during this procedure, you must take adequate measures to protect your health and safety, as well as to dispose of these hazardous materials.

How to Remove Solder Contamination

The following steps will guide you through the process of removing the contamination:

• Clean the circuit board thoroughly.
• Use plating tape to isolate the affected area and protect adjoining areas and components from the chemicals you’ll be using.
• Apply solder over all of the contaminated areas.
• Use a copper solder wicking braid and a soldering iron to clear away as much of the solder as possible from the connectors.
• Clean the affected area properly.
• Use stripping solution to remove the rest of the solder. Once the base material is exposed, use water to clean the affected area.
• With an abrasive pad, carefully buff the contacts to clean off any remaining contamination.

Steps to Restore Clean Connectors

Now that the connectors are clean, it’s time to restore them by covering them with electroplated gold:

• Connect one lead to the plating probe, which has an anode covered in absorbent material attached to the tip.
• Connect the other lead to the connectors that need to be plated.
• Dip the anode into the plating solution and move it across the connectors. Note that you must make a reliable bus connection to all the contacts that need to be plated. You can do this by using a spring-loaded pin fixture to create a mechanical connection to each individual contact or by using conductive paint to coat the inboard tips of the contacts, soldering a wire to the connection circuit or inboard tip of each contact or connecting to each contact with a mechanical probe.
• Submerge the plating probe in the electroclean solution, and let it saturate the material.
• Briskly swab the surface you want to plate with the probe.
• Rinse the surface with water. If you see any dark or burned patches on the contacts, gently burnish them with an abrasive pad and rinse again. Take care to keep the affected area wet at all times, since water will prevent any oxidation.
• Cover the contacts with the nickel plating solution and rinse the area with water.
• Repeat the process for the hard gold plating solution.
• After rinsing the area, remove the tape, clean the assembly with water again and dry it with a clean cloth or wipe.
• Mask the contacts with high-temperature tape, and remove the conductive paint or wire.
• Use deionized water to clean the entire area.

For more information on restoring gold edge connectors, please fill out our contact form or call (888) 406-2830.