Circuit Board Repair Guide > Base Board Repair > 3.4.1 How to Repair Minor Damage to Key and Slot Openings

How to Repair Minor Damage to Key and Slot Openings

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 circuit board repair procedure is used to repair minor damage to a key slot, or other cutout in a printed circuit board or printed circuit board assembly. The damaged area is repaired using high strength circuit board epoxy.

Caution
Care should be taken to limit the application of epoxy to the specific areas desired and to avoid damage to the conductive patterns, contacts and components.

IPC Acceptability References
IPC-A-610 2.0 Externally Observable Characteristics
IPC-A-600 10.0 Laminate Conditions
 
Damaged key slot in base board needs repair
Damaged Key Slot

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
IPC7721 3.4.1 Key and Slot Repair, Epoxy Method

Tools and Materials
Alcohol Swabs - Self-saturating Isopropyl alcohol swabs. Squeeze handle to release alcohol.
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.
Color Agents - Use to tint the color of epoxy used for solder mask repair or circuit base board repair.
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.
Micro Drill System - Versatile power tool for milling, drilling, grinding, cutting and sanding circuit boards.
Ball Mills, Abrasives, Cutting Tools - Ball mills, abrasives and cutting tools for working on circuit boards.
Micro Probes - Use to dispense a minute amount of adhesive and for micro-positioning of small objects.
Oven - General purpose oven for drying, baking and curing epoxies.
Scraper - Hardened stainless steel tip for scraping solder mask and removing defects.
Wipes - Nonabrasive, low-linting wipes for cleanup.

3.4.1 Key and Slot Repair, Epoxy Method

Printed Board Type: R/W  |  Skill Level: Advanced  |  Conformance Level: High  |  Rev.: D  |  Rev. Date: Jul 7, 2000

Mill away damaged board base material

Fig. 1: Mill away the damaged
board base material using a
Micro Drill System and ball mill.






1.    Clean the area to be filled, including the edges.
 
2.  Mill away the damaged board base material using a Micro Drill System and ball mill. All damaged base board material must be removed. No fibers of laminate material should be exposed at the surface of the keyslot. (See Figure 1).
 
  Note
To clearly see that all damaged material has been removed, flood the area with alcohol or solvent. Damaged internal fibers of the base material will show up clearly.
 
  Caution
Abrasion operations can generate electrostatic charges.
 
3.  Remove all loose material and clean the area.
 
4.  Apply High Temperature Tape to the surface of the circuit board adjacent to the slot. The tape should protect any adjacent contacts or components.
 
  Note
The circuit board may be preheated prior to filling the area with epoxy. A preheated PC Board will allow the epoxy to easily flow and level out. Epoxy applied to an unheated circuit board may settle below the circuit board surface as the epoxy cures.
 
5.  Mix the epoxy. If desired, add color agent to the mixed epoxy to match the PC board color.
 
Apply epoxy to edges of key slot

Fig. 2: Apply epoxy to the edges
of the key slot using a mixing
stick or micro probe.

6.  Apply a small amount of epoxy to the edges of the slot. A mixing stick sharpened at the end, or a micro probe may be used. (See Figure. 2).
 
  Note
A slight overfill of epoxy may be desired to allow for shrinkage when epoxy cures.
 
  Note
The circuit board may be turned on its side to keep the epoxy in place while it cures.
 
7.  Cure the epoxy per Procedure 2.7 Epoxy Mixing and Handling.
 
  Caution
Some components may be sensitive to high temperature.
 
8.  After the epoxy has cured remove the tape.
 
9.  If needed use a knife or scraper and scrape off any excess epoxy.
 
10.  If precision is required, machine the edges of the slot using a milling machine or Precision Drill System and appropriate milling cutter. Use great care to correctly relocate the slot.
 
  Note
If needed, apply additional thin coating to seal any scraped areas.
 
11.  Clean the area.
   
Completed key slot repair

Fig. 3: Completed key slot repair.


Evaluation
   
1.  Visual examination and measurement of key slot location and dimension.
 


Special Order. Usually ships within 3 business days from Haverhill, MA, USA. For customer service call 1-519-651-3060.

How to purchase.                                                           View cart Minimum order $50 + shipping
Image Description Part No., Price and Quantity
Alcohol Swab Alcohol Swabs (package of 50), 235-1000-50

Self-saturating foam swabs 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

 
Color Agents for Circuit Boards Color Agent, Green, 115-9348

Use to tint epoxy for solder mask and base board repair. Color agent may also be applied directly to the circuit board surface for color matching. Supplied in 1 oz. (29 ml) collapsible metal tubes. MSDS

115-9348

$19.95 each

 
Color Agents for Circuit Boards Color Agent, Light Green, 115-9358

Use to tint epoxy for solder mask and base board repair. Color agent may also be applied directly to the circuit board surface for color matching. Supplied in 1 oz. (29 ml) collapsible metal tubes. MSDS

115-9358

$19.95 each

 
High Temperature Tape Discs 235-3050 High Temp. 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

 
Micro Probe 355-3102-5 Micro Probes (package of 5), 355-3102-5

These super-sharp probes are manufactured from high quality stainless steel. They include a plastic grip for easy handling. These inexpensive, disposable probes are ideal for dispensing a minute amount of epoxy, and for micro-positioning of small objects.

Probe Tip - .006" Diameter x .50" long

Enlarge

355-3102-5

$4.95 pkg/5

 
Scraper 335-3197 Scraper, 335-3197

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



Enlarge
335-3197

$9.95 each

 

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



2CheckOut.com Inc. is a payment facilitator for goods provided by ELAB (Engineering Lab). View cart

Payment methods accepted: American Express, Visa, MasterCard, Discover, Diners Club, JCB and Paypal.

Depending on issuing bank, charges on credit card statements should appear as 2CO.COM*ELAB.

If you use Paypal, your credit card statement will show Paypal*2CheckoutCO as the merchant.

Import duties and Value Added Tax will be collected at time of delivery for all shipments outside the USA.


Links to Related Products


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 the most popular circuit board repair kit we sell.


Micro Drill System used for drilling, grinding, cutting circuit boards   Micro Drill System 110-4105
The Micro Drill System is a repair technician's dream and is ideal for milling, drilling, grinding, cutting and sanding circuit boards. It removes coating, cuts circuits, cuts leads, drills holes, cuts slots, shapes FR4 and performs many other procedures using various interchangeable bits. Unlike most hand-held tools, the Micro Drill has a tiny, high speed DC motor in the hand piece, eliminating cumbersome drive cables and giving you better control. A separate power supply keeps the hand piece lightweight and reduces operator fatigue. Base unit has controls for forward/reverse and speed up to 45,000 RPM.



Copyright and Disclaimer Notice    Phone: 1-519-651-3060    Ships From: Haverhill, MA 01835 USA

Related Items
Professional Repair Kit | PCB Tracks | Circuit Frames | Prototyping Boards | Surface Mount Resistor Kits | Surface Mount Capacitor Kits