Circuit Board Repair Guide > Jumper Wires and Component Modification Procedures > 6.2.2 Using Jumper Wires, BGA Components, Through Board Method

Using Jumper Wires, BGA Components, Through Board Method

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 add a jumper at a BGA site by running the jumper through a hole in the circuit board. This procedure is normally used for engineering changes or modifications.

Note
This method requires precision milling equipment and highly trained technicians. This method is used when there is a buried via, and other methods of terminating to the opposite side are not an option.

IPC Acceptability References
IPC-A-600 2.0 Externally Observable Characteristics
IPC-A-610 10.0 Discrete Wiring

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
CTC 6.1 How to Use Jumper Wires
CTC 9.2.1 Development of a BGA Component Rework Profile Using the Standard Method
CTC 9.3.1 Hot Gas Method for Eutectic Solder Ball BGA Rework

Tools and Materials
Circuit Tracks      
Cleaner
End Mills
Epoxy
Flux, Liquid
Knife
Microscope
Milling System      
Oven
Precision Drill System      
Scraper
Solder
Soldering Station      
Tape, Kapton
Teflon Sleeving
Tweezers
Wipes

6.2.2 Jumper Wires, BGA Components, Through Board Method

Printed Board Type: R/F/C  |  Skill Level: Expert  |  Conformance Level: High  |  Rev.: B  |  Rev. Date: Jul 7, 2000

Mill hole through board and insert Teflon sleeve

Figure 1: Mill a hole through the board
and insert a Teflon sleeve.


1. 
Clean the area.
 
2. 
Remove the BGA component if installed, remove excess solder from the pads, and clean and inspect the site.
   
3. 
Remove solder mask from the via pad terminating to the subject BGA pad. Do not remove any solder mask from the "dog bone" area.
   
4. 
Mill a hole through the board at the precise coordinates using a Precision Drill System and End Mill of the appropriate size. (See Figure 1 and 5).
   
 
Note
Although both power and ground planes may be cut, inner layer signal traces must be avoided.
   
5.  Carefully inspect the milled hole and clean the area.
   
6. 
Insert an appropriately sized Teflon sleeve into the milled hole. This sleeve will insulate the new conductor and prevent shorting to the inner layers. (See Figure 1).
   
Insert copper Circuit Track into plated hole

Figure 2: Insert a copper Circuit Track
into the plated hole and Teflon sleeve.


7. 
Select a Circuit Track to match the width of the circuit to be installed. Cut a length approximately as needed. The overlap solder connection should be a minimum of 2 times the circuit width. (See Table 1).
   

Table 1 - Common Circuit Track Sizes

Part No. Thickness Width
115-5204 .002" .004"
115-5206 .002" .006"
115-5208 .002" .008"
115-5210 .002" .010"
115-5312 .003" .120"
115-5315 .003" .015"
115-5520 .005" .020"
115-5530 .005" .030"

8. 
Gently abrade the top and bottom of the new Circuit Track (PCB Track) with the buffer to remove any oxidation and clean.
   
 
Note
If needed, the ends of the Circuit Track may be tinned with solder prior to lap soldering in place.
   
9. 
Insert one end of the Circuit Track into the plated hole connected to the BGA pad. Insert the opposite end through the Teflon sleeve. (See Figure 2).

Solder Circuit Track to plated hole connected to BGA pad

Figure 3: Solder the Circuit Track to the
plated hole connected to the BGA pad.


10.
Apply a small amount of liquid flux and lap solder the Circuit Track to the plated hole connected to the BGA pad using solder and a soldering iron. Make sure the new circuit is properly aligned. (See Figure 3).
Overcoat new connection with epoxy

Figure 4: Overcoat the new connection
with epoxy.


11. Clean the area.
   
12. Mix epoxy per procedure 2.7.
   
13.
Coat the top and sides of the new circuit with liquid circuit board epoxy. The epoxy bonds the new circuit to the base board material and insulates the circuit. (See Figure 4).
   
  Note
Keep the epoxy height below the BGA pad level.
   
  Caution
Some components may be sensitive to high temperature.
   
14. Clean the board as required.
   
15. Install a new BGA per applicable procedures.
   
16.
Solder a jumper wire to the exposed Circuit Track on the opposite side of the circuit board. Route and terminate the jumper wire as needed.
   
Precision Drill System used for milling teflon sleeved hole

Figure 5: Precision Drill System used
for milling the teflon sleeved hole.
Evaluation
   
1.  Visual examination for alignment and overlap of new circuit.
   
2.  Visual examination of epoxy coating for texture and color match.
   
3.  Electrical tests as applicable.




Links to Related Products


Circuit Track Kit used to repair damaged PCB tracks  
Circuit Track Kit 201-3130
Thanks to Circuit Tracks, it's now easier than ever to repair damaged circuits. Circuit Tracks are rectangular shaped conductors made of 99.9% pure copper. The rectangular ribbons closely conform to the original conductor dimensions. The replacement Circuit Track is bonded in place using a prepackaged epoxy which is included in this kit. The Circuit Track Kit is a great time and labor-saver and an easy solution to repairing missing or damaged circuits and conductors.



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