Circuit Board Repair Guide > Conductor Repair Procedures > SMT Pad Repair

How to Repair Damaged SMT Pads Using New Pads & 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 SMT pad repair procedure is used to replace damaged surface mount pads with new dry film, adhesive backed pads. The new SMT pads are bonded to the printed circuit board surface using a specially designed circuit bonding system or bonding iron.

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 surface mount pads. The new pads are fabricated from copper foil. They are available in hundreds of sizes and shapes and are generally supplied solder plated. If a special size or shape is needed it can be custom fabricated.
 
Damaged surface mount pad needs replacement
Damaged Surface Mount Pad

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 4.7.2 Surface Mount Pad Repair, Film Adhesive Method

Tools and Materials
Alcohol Swabs - Self-saturating Isopropyl alcohol swabs. Squeeze handle to release alcohol.
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, SMT Pads - 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.
Cleaning Brushes - Disposable brushes for use with solvents for cleaning and application of coatings.
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.

4.7.2 Surface Mount Pad Repair, Film Adhesive Method

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

Remove defective SMT pad and solder mask

Figure 1: Remove the defective SMT
pad and remove solder mask from
the connecting circuit.

1.  Clean the area.
 
2. Remove the defective surface mount pad and a short length of the connecting circuit. (See Figure 1).
 
3. Use a knife and scrape off any epoxy residue, contamination or burned material from the board surface.
 
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.
 
7. The area for the new surface mount pad on the board surface must be smooth and flat. If internal fibers of the board are exposed, or if there are deep scratches in the surface, they should be repaired. Refer to appropriate procedure.
 
Select replacement SMT pad

Figure 2: Select a replacement SMT
pad that matches the missing pad.


8.  Select a replacement SMT pad that most closely matches the SMT pad to be replaced from the SMT Pad Circuit Frames shown below or choose one from the large variety of replacement circuits which are included when you purchase the Professional Repair Kit. If a special size or shape is needed they can be custom fabricated. (See Figure 2).

Note
New surface mount pads are fabricated from copper foil. The foil is plated on the top side with solder, and an adhesive bonding film is applied to the bottom side.
Scrape off adhesive on back of pad

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


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

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

Figure 4: Cut out the new surface
mount pad. Cut from the plated side.


10. Cut out and trim the new surface mount pad. Cut out from the plated side. Cut the length to provide the maximum allowable circuit overlap for soldering. Minimum 2 times the circuit width. (See Figure 4).
Place surface mount pad using tape

Figure 5: Place the new surface
mount pad in place using High
Temperature Tape.


11. Place a piece of High Temperature Tape over the top surface of the new pad. Place the new SMT pad into position on the circuit board surface using High Temperature Tape to help in alignment. (See Figure 5).
 
12. Select a bonding tip with a shape to match the shape of the new surface mount pad. See bonding tip chart below.

Note
The tip used for bonding should be as small as possible but should completely cover the entire surface of the new pad.
Bond new SMT pad using Bonding System

Figure 6: Bond the new SMT pad
using a Bonding System or
Bonding Iron with the 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 surface mount pad. Apply pressure as recommended in the manual of the repair system or repair kit for 5 seconds to tack the new pad 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 pad to slide out of position.
 
14. Gently place the bonding tip directly onto the new surface mount pad. Apply pressure as recommended in the manual of the repair system or repair kit for an additional 30 seconds to fully bond the pad. After the bonding cycle remove the tape used for alignment. The new pad is fully cured. Carefully clean the area and inspect the new SMT pad for proper alignment.
 
Surface mount pad repair completed

Figure 7: Surface mount pad repair
completed.
15. If the new pad 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 pad 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 pad 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. Mix epoxy and coat the lap solder joint connection. Cure the circuit epoxy per Procedure 2.7 Epoxy Mixing and Handling.

Note
Additional epoxy can be applied around the perimeter of the new pad to provide additional bond strength.

Caution
Some components may be sensitive to high temperature.
 
17. Apply surface coating to match prior coating as required.
 
  Evaluation
 
1.  Visual examination.
 
2.  Measurement of new pad width and spacing.
 
3.  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 - Bright Tin:     .0001" (.0025 mm) Bright Tin (Lead Free)


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

SMT Pad Circuit Frames              Minimum order requirement $50 plus shipping.

Image Description                                                            View cart Part Number
CS004085AS SMT Pads .004" x .085" Circuit Frame CS004085AS

SMT Pads .004" x .085" (.101mm x 2.159mm)

Plating: Bright Tin

Enlarge
CS004085AS

US $44.00

 
CS011061AS SMT Pads .011" x .061" Circuit Frame CS011061AS

SMT Pads .011" x .061" (.279mm x 1.549mm)

Plating: Bright Tin

Enlarge
CS011061AS

US $44.00

 
CS012060AS SMT Pads .012" x .060" Circuit Frame CS012060AS

SMT Pads .012" x .060" (.304mm x 1.524mm)

Plating: Bright Tin

Enlarge
CS012060AS

US $44.00

 
CS012100AS SMT Pads .012" x .100" Circuit Frame CS012100AS

SMT Pads .012" x .100" (.304mm x 2.540mm)

Plating: Bright Tin

Enlarge        Recommended Bonding Tip: 115-2308
CS012100AS

US $44.00

 
CS020028AS SMT Pads .020" x .028" Circuit Frame CS020028AS

SMT Pads .020" x .028" (.508mm x .711mm)

Plating: Bright Tin

Enlarge
CS020028AS

US $44.00

 
CS025080AS SMT Pads .025" x .080" Circuit Frame CS025080AS

SMT Pads .025" x .080" (.635mm x 2.032mm)

Plating: Bright Tin

Enlarge
CS025080AS

US $44.00

 
CS025080BS SMT Pads .025" x .080" Circuit Frame CS025080BS

SMT Pads .025" x .080" (.635mm x 2.032mm)

Plating: Bright Tin

Enlarge
CS025080BS

US $44.00

 
CS028185AS SMT Pads .028" x .185" Circuit Frame CS028185AS

SMT Pads .028" x .185" (.711mm x 4.699mm)

Plating: Bright Tin

Enlarge        Recommended Bonding Tip: 115-2318
CS028185AS

US $44.00

 
CS030055AS SMT Pads .030" x .055" Circuit Frame CS030055AS

SMT Pads .030" x .055" (.762mm x 1.397mm)

Plating: Bright Tin

Enlarge        Recommended Bonding Tip: 115-2312
CS030055AS

US $44.00

 
CS034030AS SMT Pads .034" x .030" Circuit Frame CS034030AS

SMT Pads .034" x .030" (.863mm x .762mm)

Plating: Bright Tin

Enlarge        Recommended Bonding Tip: 115-2310
CS034030AS

US $44.00

 
CS038090AS SMT Pads .038" x .090" Circuit Frame CS038090AS

SMT Pads .038" x .090" (.965mm x 2.286mm)

Plating: Bright Tin

Enlarge        Recommended Bonding Tip: 115-2308
CS038090AS

US $44.00

 
CS039039AS SMT Pads .039" x .039" Circuit Frame CS039039AS

SMT Pads .039" x .039" (.991mm x .991mm)

Plating: Bright Tin

Enlarge
CS039039AS

US $44.00

 
CS040070AS SMT Pads .040" x .070" Circuit Frame CS040070AS

SMT Pads .040" x .070" (1.016mm x 1.778mm)

Plating: Bright Tin

Enlarge        Recommended Bonding Tip: 115-2312
CS040070AS

US $44.00

 
CS040110AS SMT Pads .040" x .110" Circuit Frame CS040110AS

SMT Pads .040" x .110" (1.016mm x 2.794mm)

Plating: Bright Tin

Enlarge        Recommended Bonding Tip: 115-2308
CS040110AS

US $44.00

 
CS045110AS SMT Pads .045" x .110" Circuit Frame CS045110AS

SMT Pads .045" x .110" (1.143mm x 2.794mm)

Plating: Bright Tin

Enlarge        Recommended Bonding Tip: 115-2308
CS045110AS

US $44.00

 
CS046106AS SMT Pads .046" x .106" Circuit Frame CS046106AS

SMT Pads .046" x .106" (1.168mm x 2.692mm)

Plating: Bright Tin

Enlarge        Recommended Bonding Tip: 115-2308
CS046106AS

US $44.00

 
CS048068AS SMT Pads .048" x .068" Circuit Frame CS048068AS

SMT Pads .048" x .068" (1.219mm x 1.727mm)

Plating: Bright Tin

Enlarge        Recommended Bonding Tip: 115-2312
CS048068AS

US $44.00

 
CS050050AS SMT Pads .050" x .050" Circuit Frame CS050050AS

SMT Pads .050" x .050" (1.270mm x 1.270mm)

Plating: Bright Tin

Enlarge        Recommended Bonding Tip: 115-2310
CS050050AS

US $44.00

 
CS051087AS SMT Pads .051" x .087" Circuit Frame CS051087AS

SMT Pads .051" x .087" (1.295mm x 2.209mm)

Plating: Bright Tin

Enlarge        Recommended Bonding Tip: 115-2318
CS051087AS

US $44.00

 
CS060080AS SMT Pads .060" x .080" Circuit Frame CS060080AS

SMT Pads .060" x .080" (1.524mm x 2.032mm)

Plating: Bright Tin

Enlarge        Recommended Bonding Tip: 115-2312
CS060080AS

US $44.00

 
CS065055AS SMT Pads .065" x .055" Circuit Frame CS065055AS

SMT Pads .065" x .055" (1.651mm x 1.397mm)

Plating: Bright Tin

Enlarge        Recommended Bonding Tip: 115-2312
CS065055AS

US $44.00

 
CS065095AS SMT Pads Frame .065" x .095" Circuit Frame CS065095AS

SMT Pads .065" x .095" (1.651mm x 2.413mm)

Plating: Bright Tin

Enlarge
CS065095AS

US $44.00

 
CS067173AS SMT Pads .067" x .173" Circuit Frame CS067173AS

SMT Pads .067" x .173" (1.701mm x 4.394mm)

Plating: Bright Tin

Enlarge        Recommended Bonding Tip: 115-2318
CS067173AS

US $44.00

 
CS071106AS SMT Pads .071" x .106" Circuit Frame CS071106AS

SMT Pads .071" x .106" (1.803mm x 2.692mm)

Plating: Bright Tin

Enlarge
CS071106AS

US $44.00

 
CS090100AS SMT Pads .090" x .100" Circuit Frame CS090100AS

SMT Pads .090" x .100" (2.28mm x 2.54mm)

Plating: Bright Tin

Enlarge
CS090100AS

US $44.00

 
CS095000AS SMT Pads .095" Diameter Circuit Frame CS095000AS

SMT Pads .095" (2.41mm) Diameter

Plating: Bright Tin

Enlarge
CS095000AS

US $44.00

 
CS095095AS SMT Pads .095" x .095" Circuit Frame CS095095AS

SMT Pads .095" x .095" (2.413mm x 2.413mm)

Plating: Bright Tin

Enlarge        Recommended Bonding Tip: 115-2320
CS095095AS

US $44.00

 
CS130177AS SMT Pads .130" x .177" Circuit Frame CS130177AS

SMT Pads .130" x .177" (3.302mm x 4.496mm)

Plating: Bright Tin

Enlarge
CS130177AS

US $44.00

 
CSV002AS SMT Pads .100" x .100" Circuit Frame CSV002AS

SMT Pads .100" x .100" (2.54mm x 2.54mm)

Plating: Bright Tin

Enlarge
CSV002AS

US $44.00

 
Alcohol Swab Alcohol Swabs (package of 50), 235-1000-50

Self-saturating foam swab filled with 99% Isopropyl alcohol. Ideal for removing flux residue and cleaning surfaces prior to soldering, coating and application of epoxy. Overall Length: 4.125". Squeeze handle until it "pops" releasing alcohol into the tip.

Enlarge
235-1000-50

$39.00 pkg/50

 
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

 
Cleaning Brush Cleaning Brushes (package of 100), 235-2106-100

Disposable brushes for use with solvents for cleaning and application of coatings.



Enlarge
235-2106-100

$29.95 pkg/100

 
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


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.


Professional Repair Kit used to repair damaged circuit boards   Professional Repair Kit 201-2100
This circuit board repair kit includes everything needed for a wide range of circuit board repair needs. The Professional Repair Kit is designed to be used for the following applications: surface mount and BGA pad repair, circuit and land repair, plated hole repair, gold edge contact repair, solder mask and base board repair. This is cl the most popular circuit board repair kit we sell.


Circuit Bonding System bonds surface mount and BGA pads   Circuit Bonding System 115-3118
The Circuit Bonding System is the best, calibrated system for bonding adhesive film backed circuits and is ideally suited for bonding small patterns including surface mount and BGA pads. This bonding press not only gives the operator better control over the bonding process, but also ensures optimal adhesion and repeatability. Includes a built-in calibration slide to maintain a regulated bonding force depending upon the circuit pattern size and shape. The digital temperature controller maintains a uniform temperature throughout the 30-second bonding cycle.

Bonding Tips
The Bonding Tips fit into the hand held Bonding Iron (part number 115-3102) and the Circuit Bonding System. 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.



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