Jumpering a PCB (Printed Circuit Board) involves creating a temporary or permanent electrical connection to bypass a broken trace, a faulty component, or to implement a modification. Here's a step-by-step guide on how to do it effectively:
Steps to Jumper a PCB
-
Identify the Problem: Determine which trace is broken, which component needs bypassing, or what connection needs to be made. A multimeter in continuity mode can be very helpful for tracing connections.
-
Prepare the Area:
- Scrape Away Resist: Carefully remove the solder mask (the protective coating) from the copper pads or traces you will be soldering to. A hobby knife or specialized scraping tool is useful for this. Be gentle to avoid damaging the copper.
- Clean the Area: Use isopropyl alcohol (IPA) and a cotton swab or brush to thoroughly clean the exposed copper. This ensures good solder adhesion.
-
Choose the Jumper Wire:
- Select a suitable gauge of wire. Thin, insulated solid-core wire (e.g., 30 AWG wire-wrapping wire) is often a good choice for fine traces. For higher current applications, use a thicker gauge. Insulated wire prevents shorts to adjacent traces.
- Consider the length of the jumper. Cut the wire slightly longer than necessary to allow for easy handling and forming.
-
Prepare the Jumper Wire:
- Strip the Ends: Use wire strippers to remove a small amount of insulation from each end of the wire. Be careful not to nick the copper conductor.
- Tin the Ends: Apply a small amount of solder to the exposed copper at each end of the wire. This makes it easier to solder the wire to the PCB pads and ensures a strong electrical connection. Use a soldering iron and a small amount of solder.
-
Solder One End of the Wire:
- Position one end of the tinned wire onto the prepared copper pad or trace.
- Apply heat from the soldering iron to both the wire and the pad simultaneously.
- Feed a small amount of solder into the joint until a good solder fillet forms.
- Remove the soldering iron. Let the joint cool completely before moving on.
-
Form the Wire (If Necessary):
- Gently bend and shape the wire to follow the desired path. Ensure the wire doesn't contact any other components or traces that could cause a short circuit.
-
Solder the Other End of the Wire:
- Position the other tinned end of the wire onto the corresponding copper pad or trace.
- Repeat the soldering process from Step 5, creating a secure solder joint.
-
Inspect the Joint:
- Visual Inspection: Check for shiny, smooth solder joints. Dull or blobby joints indicate a poor connection (cold solder joint).
- Continuity Test: Use a multimeter to confirm continuity between the two points you've jumpered.
-
Secure the Jumper Wire (Optional):
- If the jumper wire is exposed to vibration or movement, you can secure it with a small amount of non-conductive epoxy or hot glue to prevent it from breaking or shorting.
Example Scenarios:
- Repairing a broken trace: Jumper from one side of the break to the other.
- Bypassing a resistor: Jumper across the resistor's terminals.
- Connecting two points on the board: Jumper between the two designated pads.
Important Considerations:
- Heat: Use a soldering iron with adjustable temperature and avoid overheating components or traces.
- Solder: Use appropriate solder for electronics work (typically rosin-core solder).
- Safety: Work in a well-ventilated area and wear safety glasses.
- Trace Width: Consider the current carrying capacity of the original trace when selecting the jumper wire gauge. A wider trace generally requires a thicker jumper wire.
- Alternatives: For more permanent and professional repairs, consider using conductive epoxy or trace repair pens for very fine traces.
Tools You'll Need:
- Soldering Iron
- Solder
- Jumper Wire
- Wire Strippers
- Hobby Knife or Scraping Tool
- Isopropyl Alcohol (IPA)
- Cotton Swabs or Brush
- Multimeter
By following these steps carefully, you can effectively jumper a PCB to restore functionality or make modifications.
