Circuit Board Repair Guide > Conductor Repair Procedures > 4.6.2 How to Repair Damaged Edge Contacts Using New Contacts & Film Adhesive

How to Repair Damaged Edge Contacts Using New Contacts & Film Adhesive

Repair Circuit Boards | Repair SMT Pads | Repair BGA Pads | Repair Lands | Repair Edge Contacts
Repair a Conductor | Plated Hole Repair | Base Board Repair | Replace Solder Mask or Coatings

This procedure is used to replace a damaged edge contact with a new edge contact which is bonded with film adhesive. The new edge contact has a dry-film adhesive backing and is bonded to the circuit board surface using a bonding iron or circuit bonding system.

Caution
It is essential that the board surface be smooth and flat. If the base material is damaged see appropriate procedure.

Note
This method uses replacement edge contacts that are fabricated from copper foil and have a dry film adhesive coating on the back. They are available in hundreds of sizes and shapes and are generally supplied nickel and gold plated. If a special size or shape is needed it can be custom fabricated.
 
Damaged edge contact needs replacement
Damaged Edge Contact

IPC Acceptability References
IPC-A-600 2.0 Externally Observable Characteristics
IPC-A-610 10.0 Laminate Conditions
 
Related Procedure References
CTC 1.0 Foreword - Circuit Board Repair Guide
CTC 2.1 Handling Electronic Assemblies
CTC 2.2.1 How to Clean a Circuit Board
CTC 2.2.2 Cleaning Circuit Boards, Aqueous Batch Process
CTC 2.5 Baking and Preheating of Printed Circuit Boards
CTC 2.7 Epoxy Mixing and Handling
IPC 7721 4.6.2 Edge Contact Repair, Film Adhesive Method

Tools and Materials
Bonding Iron, 120 VAC - Delivers the optimal heat for curing adhesive bonding film.  Bonding Tips sold separately.
Bonding Tips - Used to cure adhesive backed circuit frames for pad, land and contact repair.
Circuit Bonding System  (optional) - System for applying heat and pressure to cure adhesive bonding film.
Circuit Frames, Edge Contacts - Replacement circuits with a dry-film adhesive backing for conductor repair.
Circuit Bond Pack - Clear, superior strength epoxy in two-compartment plastic package.
Cleaner - General purpose cleaner for removing contamination.
File - High carbon steel needle file perfect for all kinds of detail work.
High Temperature Tape Discs - High temperature polyimide tape discs, .50" diameter.
Knife with #16 Blades - A must-have tool for precise cutting, scraping and trimming.
Microscope - It is a challenge to undertake precision repair without a good microscope.
Oven - General purpose oven for drying, baking and curing epoxies.
Scraper - Hardened stainless steel tip for scraping solder mask and removing defects.
Soldering Iron, Solder and Flux - A well maintained soldering iron is a must at every tech bench.
Tweezer, Point Tip - Fine point tweezers for precision work.
Wipes - Nonabrasive, low-linting wipes for cleanup.

4.6.2 Edge Contact Repair, Film Adhesive Method

Printed Board Type: R/F/W/C  |  Skill Level: Advanced  |  Conformance Level: High  |  Rev.: D  |  Rev. Date: May 8, 2001

Remove defective edge contact and solder mask

Fig. 1: Remove the defective edge
contact and remove solder mask
from the connecting circuit.


1.  Clean the area.
 
2. Remove the defective edge contact and a short length of the connecting circuit. Heat from a soldering iron will allow the old contact to be removed more easily. (See Figure 1).
 
3. Use the knife and scrape off any epoxy residue, contamination or burned material from the board surface.

Caution
Abrasion operations can generate electrostatic charges.
 
4.  Scrape off any solder mask or coating from the connecting circuit. (See Figure 1).
 
5. Clean the area.
 
6. Apply a small amount of liquid flux to the connection area on the board surface and tin with solder. Clean the area. The length of the overlap solder connection should be a minimum of 2 times the circuit width.
 
Select replacement contact that matches missing contact

Fig. 2: Select replacement contact
that matches the missing contact.


7. The area for the new edge contact on the board surface must be smooth and flat. If internal fibers of the board are exposed or deep scratches exist in the surface they should be repaired. Refer to appropriate procedure.
 
8.  Select a new edge contact that most closely matches the edge contact to be replaced from the Edge Contact Circuit Frames shown below or choose one from the replacement edge contacts which are included with your purchase of the Gold Contact Repair Kit. (See Figure 2).

Note
The new replacement edge contact may be trimmed from copper sheet.
Scrape off adhesive from new edge contact

Fig. 3: Scrape off the adhesive
bonding film from the solder joint
area on the back of new contact.


9.  Before trimming out the new edge contact carefully scrape off the adhesive film from the solder joint connection area on the back of the new edge contact. (See Figure 3).

Caution
Scrape off the epoxy backing only from the joint connection area. When handling the replacement contact, avoid touching the epoxy backing with your fingers or other materials that may contaminate the surface and reduce the bond strength.
Cut out new edge contact

Fig. 4: Cut out new edge contact.
Cut from the plated side.


10. Cut out and trim the new edge contact. Cut out from the plated side. Cut the length to provide the maximum allowable joint if lap soldering. Minimum 2 times the circuit width. Leave the new edge contact extra long. The excess material will be trimmed after bonding. (See Figure 4).
Place new edge contact

Fig. 5: Place new edge contact
in place using High Temperature
Tape.


11. Place a piece of High Temperature Tape over the top surface of the new edge contact. Position the new edge contact on the circuit board surface using the tape to aid in alignment. (See Figure 5).

Note
Allow the edge contact to overhang the edge of the circuit board.
 
12. Select a bonding tip with a shape to match the shape of the new edge contact. See bonding tip chart.

Note
The bonding tip should be as small as possible but completely cover the entire surface of the new edge contact.
 
Bond new edge contact with a Bonding System.

Fig. 6: Bond new edge contact
with a Bonding System or
Bonding Iron with appropriate
Bonding Tip.


13. Position the circuit board so that it is flat and stable. Gently place the hot bonding tip onto the High Temperature Tape covering the new edge contact. Apply pressure as recommended in the manual of the repair system or repair kit for 5 seconds to tack the contact in place. Carefully peel off the tape. (See Figure 6).

Caution
Excessive bonding pressure may cause measling in the circuit board surface or may cause the new contact to slide out of position.
 
14. Gently place the bonding tip directly onto the contact. Apply pressure as recommended in the manual of the repair system or circuit board repair kit for an additional 30 seconds to fully bond the contact. After the bonding cycle remove the tape used for alignment. The new edge contact is fully cured. Carefully clean the area and inspect the new edge contact for proper alignment.
 
File edge contact to blend with existing bevel

Fig. 7: File overhanging piece of
new edge contact to blend with
existing bevel.


15. If the new edge contact has a connecting circuit apply a small amount of liquid flux to the lap solder joint connection area and solder the circuit from the new edge contact to the circuit on the circuit board surface. Use minimal flux and solder to ensure a reliable connection. Tape may be placed over the top of the new edge contact to prevent excess solder overflow.

Note
If the configuration permits, the overlap solder joint connection should be a minimum of 3.00 mm (0.125") from the related termination. This gap will minimize the possibility of simultaneous reflow during soldering operations. Refer to 7.1 Soldering Basics.
 
16. Remove the tape and clean the area.
Edge contact repair completed

Fig. 8: Gold contact repair
completed.
17. Trim the extending edge of the new edge contact with a file. File parallel to the beveled edge until the excess material has been removed. (See Figure 7).
 
18. If sealing the lap solder joint connection is required, mix epoxy and coat the lap solder joint connections. Cure the epoxy per Procedure 2.7 Epoxy Mixing and Handling.

Caution
Some components may be sensitive to high temperature.

Note
Additional liquid circuit board epoxy can be applied around the perimeter of the new edge contact to provide additional bond strength.
 
19. Apply surface coating to match prior coating as required.
 
  Evaluation
 
1.  Visual examination, measurement of new contact width and spacing.
 
2.  Electrical continuity measurement.
 

Circuit Frame Material Specifications

Overall Frame Size: 2.25" x 1.50" (57 mm x 38 mm)
Base Material: Rolled annealed copper foil .0014" (.036 mm) thick.
Adhesive Backing: B-staged modified acrylic film adhesive .002" (.051 mm) thick.
Bonding Temperature: 475°F +/- 25°F (246°C +/- 14°C)
Bonding Time: 30 seconds
Peel Strength: Minimum 8 lbs/inch (1.43 kg/cm) after cure to FR-4 material.
Shelf Life: 1 year minimum. Each Circuit Frame package is stamped with the expiration date.
Shelf-Life items may not be returned for credit.
Plating Option - Nickel/Gold:     .000050" (.00127 mm) Gold over .000100" (.00254 mm) Nickel


Special Order. Ship within 3 business days. How to purchase.

Edge Contact Circuit Frames       Minimum order requirement $50 plus shipping.

Image Description                                                            View cart Part Number
CC035080AG Contacts .035" x .080" Circuit Frame CC035080AG

Contacts .035" x .080" (.889mm x 2.032mm)

Plating: Nickel/Gold

Enlarge        Recommended Bonding Tip: 115-2312
CC035080AG

US $149.00

 
CC038255AG Contacts .038" x .250" Circuit Frame CC038255AG

Contacts .038" x .250" (.965mm x 6.350mm)

Plating: Nickel/Gold

Enlarge        Recommended Bonding Tip: 115-2318
CC038255AG

US $149.00

 
CC050060AG Contacts .050"/.060" Circuit Frame CC050060AG

Contacts .050"/.060" (1.27mm/1.52mm)

Plating: Nickel/Gold

Enlarge        Recommended Bonding Tip: 115-2318
CC050060AG

US $149.00

 
CC050300AG Contacts .050" x .300" Circuit Frame CC050300AG

Contacts .050" x .300" (1.27mm x 7.62mm)

Plating: Nickel/Gold

Enlarge        Recommended Bonding Tip: 115-2318
CC050300AG

US $149.00

 
CC070080AG Contacts .070"/.080" Circuit Frame CC070080AG

Contacts .070"/.080" (1.78mm/2.03mm)

Plating: Nickel/Gold

Enlarge        Recommended Bonding Tip: 115-2318
CC070080AG

US $149.00

 
CC076190AG Contacts .076" x .190" Circuit Frame CC076190AG

Contacts .076" x .190" (1.93mm x 4.83mm)

Plating: Nickel/Gold

Enlarge        Recommended Bonding Tip: 115-2318
CC076190AG

US $149.00

 
CC085360AG Contacts .085" x .360" Circuit Frame CC085360AG

Contacts .085" x .360" (2.16mm x 9.14mm)

Plating: Nickel/Gold

Enlarge        Recommended Bonding Tip: 115-2322
CC085360AG

US $149.00

 
CC090300AG Contacts .090" x .300" Circuit Frame CC090300AG

Contacts .090" x .300" (2.28mm x 7.62mm)

Plating: Nickel/Gold

Enlarge        Recommended Bonding Tip: 115-2322
CC090300AG

US $149.00

 
Liquid circuit board epoxy Circuit Bond Pack  MSDS, 115-3302

Clear, low viscosity, superior strength epoxy, precisely measured out into a two-compartment plastic package so it's easy to use and there's no measuring (2 gram). Shelf life: 6 months minimum.

Enlarge
115-3302

$12.95 each

 
File 115-3132 File

High carbon steel needle file perfect for all kinds of detail work. File can be used to put the perfectly beveled edge on replacement gold edge contacts.

Enlarge
115-3132

$9.95 each

 
High Temperature Tape Discs 235-3050 High Temperature Tape Discs, .50" Diameter, 235-3050

High temperature tape discs are made of polyimide film with 1.5 mil of silicone adhesive that will not leave any residue. They can withstand temperatures of up to 500°F (260°C).
235-3050

US $5.95 pkg/60

 
Knife 355-0614 Knife with #16 Blades, 355-0614

A must-have tool for precise cutting, scraping and trimming. Includes five #16 blades.


Enlarge
355-0614

$9.95 each

 
Scraper 335-3197 Scraper, 335-3197

Hardened stainless steel tip for scraping solder mask and removing defects.



Enlarge
335-3197

$9.95 each

 
Tweezer, Point Tip 335-5185 Tweezer, Point Tip, 335-5185

Fine point tweezers are perfect for precision work.



Enlarge
335-5185

$9.95 each

 

Products above ship direct from manufacturer and are special order/non-returnable. Will ship within 3 business days.



 
Bonding Iron and Bonding Tips

Bonding Tips fit into the hand held Bonding Iron (part no. 115-3102 for 120 VAC and part no. 115-3103 for 230 VAC) and the Circuit Bonding System (part no. 115-3118 which includes voltage converter for 120 VAC and 220 VAC). The bottom machined surface of each Bonding Tip is used to apply heat and pressure to bond the adhesive backed replacement pads, edge contacts, and lands to the circuit board surface. All our Bonding Tips are machined from high grade aluminum.

Image Description                                                            View cart Part Number
Bonding Iron 115-3102 Bonding Iron, 120 VAC, 115-3102

The Bonding Iron is set at the optimal temperature for curing the bonding film used to repair damaged surface mount pads, lands, edge contacts and other circuit board patterns. Bonding Tip is not included with purchase of Bonding Iron so remember to also select and purchase a Bonding Tip to match the shape of the new pad or circuit. Enlarge

115-3102

US $109.00

 
Bonding Iron 115-3103 Bonding Iron, 230 VAC, 115-3103

The Bonding Iron is set at the optimal temperature for curing the bonding film used to repair damaged surface mount pads, lands, edge contacts and other circuit board patterns. Bonding Tip is not included with purchase of Bonding Iron so remember to also select and purchase a Bonding Tip to match the shape of the new pad or circuit. Enlarge

115-3103

US $179.00

 

115-2104 Tapered Tip
Bonding Tip 115-2104

Tapered



115-2104

US $45.00

 

115-2201 Circular Tip .025"
Bonding Tip 115-2201

.025" (.635mm) Diameter

Circular

115-2201

US $45.00

 

115-2202 Circular Tip .060"
Bonding Tip 115-2202

.060" (1.52mm) Diameter

Circular

115-2202

US $45.00

 

115-2204 Circular Tip .080"
Bonding Tip 115-2204

.080" (2.03mm) Diameter

Circular

115-2204

US $45.00

 

115-2205 Circular Tip .035"
Bonding Tip 115-2205

.035" (.89mm) Diameter

Circular

115-2205

US $45.00

 

115-2206 Circular Tip .120"
Bonding Tip 115-2206

.120" (3.05mm) Diameter

Circular

115-2206

US $45.00

 

115-2301 Small Rectangle Tip .010" x .080"
Bonding Tip 115-2301

.010" x .080" (.25mm x 2.03mm)

Small Rectangle

115-2301

US $45.00

 

115-2306 Small Rectangle Tip .040" x .060"
Bonding Tip 115-2306

.040" x .060" (1.02mm x 1.52mm)

Small Rectangle

115-2306

US $45.00

 

115-2308 Small Rectangle Tip .045" x .110"
Bonding Tip 115-2308

.045" x .110" (1.14mm x 2.79mm)

Small Rectangle

115-2308

US $45.00

 

115-2310 Small Rectangle Tip .050" x .050"
Bonding Tip 115-2310

.050" x .050" (1.27mm x 1.27mm)

Small

115-2310

US $45.00

 

115-2312 Small Rectangle Tip .060" x .080"
Bonding Tip 115-2312

.060" x .080" (1.52mm x 2.03mm)

Small Rectangle

115-2312

US $45.00

 

115-2316 Small Rectangle Tip .080" x .120"
Bonding Tip 115-2316

.080" x .120" (2.03mm x 3.05mm)

Small Rectangle

115-2316

US $45.00

 

115-2318 Large Rectangle Tip .080" x .500"
Bonding Tip 115-2318

.080" x .500" (2.03mm x 12.70mm)

Large Rectangle

115-2318

US $45.00

 

115-2320 Small Rectangle Tip .095" x 095"
Bonding Tip 115-2320

.095" x .095" (2.41mm x 2.41mm)

Small

115-2320

US $45.00

 

115-2322 Large Rectangle Tip .120" x .500"
Bonding Tip 115-2322

.120" x .500" (3.05mm x 12.70mm)

Large Rectangle

115-2322

US $45.00

 

Products above ship direct from manufacturer and are special order/non-returnable. Will ship within 3 business days.



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Links to Related Products


Gold Contact Repair Kit used to repair damaged gold edge contacts   Gold Contact Repair Kit 201-1120
Repairing gold edge contacts on circuit boards is delicate work, but this circuit board repair kit helps make the process easier and more reliable. You simply select the correct size and shape of gold plated contact from the circuit frames which are included in this kit and bond it in place. The replacement circuits have a dry film, adhesive backing that is activated and cured with heat and pressure. This gold contact repair method restores your boards to their original level of performance and reliability.


Circuit Frames used to replace pads, lands and conductors   Circuit Frames
Circuit Frames allow you to replace damaged surface mount pads, lands and conductors without the mess of liquid epoxy, with a bond strength equal to the original, in just a few minutes. Circuit Frames come in a wide variety of shapes and sizes, all with a dry-film adhesive backing, activated and cured with heat and pressure. Trim out the circuit you need and bond it to the circuit board surface using a Bonding Iron or Circuit Bonding System with the appropriate Bonding Tip.



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