global Laptop and motherboard repair tutorial | Page 86

Use a small screwdriver to cut away at the burned portion of the circuit board. Note that the
material will be beveled at the edges once the burn is completely cut from the circuit board.
Clean the circuit board with solvent to remove all excess particles. Use a combination of
powdered fiberglass and epoxy liquid to fill the portion of the circuit board that was previously cut
away. The edge of the board and delaminated layers should be completely filled.
Smooth the surface of the newly repaired circuit board using a small-tip soldering iron. If
necessary, you will drill new holes into the repaired area of the motherboard/PCB, where the screws
were inserted to hold the board in place. Use a small drill bit, as the area you are working on is also
small.
Inspect the board with magnification before starting any repair.
Repair a small burnt section by simply scraping away carbonized material with a hobby knife.
Grind a scrap board for fiberglass filler to mix with epoxy, forming a paste. This goes into the
excavated section. Lay the circuit board flat while the epoxy cures.
Halfway through the curing process, the paste will dry to a semi-solid gel form. Use a blade to cut
away the excess. Hold it flat against the board and use a gentle sawing motion.
Inspect any faulty trace on the surface of the board carefully. When traces, pads or plated-through
holes are damaged, the repair becomes more complex. Having a ―known workingǁ motherboard is
optimal for comparison; though a drawing or photograph can be helpful.
Cut away burnt traces or pads with the hobby knife. Use a grinder if available (a Dremel will do
nicely) to remove charred fiberglass. Once again, apply a paste of epoxy and ground fiberglass in the
cavity and cut it down flush with the top of the board.
When the epoxy is fully cured, scrape the remaining ends of the trace clean. This must be done
carefully, as the traces are thin and easily damaged. They should be scrapped down to clean, bright
copper, then fluxed and tinned with solder. Cut a new, replacement trace if needed (use copper tape),
it should be the same width as the original. Simply lay it in place and sweat it down with a soldering
iron.
Seal any short-repaired trace with a humidity barrier to prevent oxidation. A long-repaired trace
can be tacked down with epoxy.
Repair a plated through hole by drilling out the burned part. A replacement looks like a tiny
funnel. Set it in place on one side of the board. Then flare it out or "swage" it on the opposite end.
This can be done by hand or with a dedicated repair fixture.
When the repair is complete, clean up with alcohol and cotton swabs to ensure that all debris is
removed. Inspect the board under magnification before applying power.