LG Flatron L1722P, Service Manual

Page: 8 / 28

- 7 -
Circuit Board Foil Repair
Excessive heat applied to the copper foil of any printed
circuit board will weaken the adhesive that bonds the foil
to the circuit board causing the foil to separate from or
"lift-off" the board. The following guidelines and
procedures should be followed whenever this condition is
encountered.
At IC Connections
To repair a defective copper pattern at IC connections use
the following procedure to install a jumper wire on the
copper pattern side of the circuit board. (Use this
technique only on IC connections).
1. Carefully remove the damaged copper pattern with a
sharp knife. (Remove only as much copper as
absolutely necessary).
2. carefully scratch away the solder resist and acrylic
coating (if used) from the end of the remaining copper
pattern.
3. Bend a small "U" in one end of a small gauge jumper
wire and carefully crimp it around the IC pin. Solder the
IC connection.
4. Route the jumper wire along the path of the out-away
copper pattern and let it overlap the previously scraped
end of the good copper pattern. Solder the overlapped
area and clip off any excess jumper wire.
At Other Connections
Use the following technique to repair the defective copper
pattern at connections other than IC Pins. This technique
involves the installation of a jumper wire on the
component side of the circuit board.
1. Remove the defective copper pattern with a sharp
knife.
Remove at least 1/4 inch of copper, to ensure that a
hazardous condition will not exist if the jumper wire
opens.
2. Trace along the copper pattern from both sides of the
pattern break and locate the nearest component that is
directly connected to the affected copper pattern.
3. Connect insulated 20-gauge jumper wire from the lead
of the nearest component on one side of the pattern
break to the lead of the nearest component on the
other side.
Carefully crimp and solder the connections.
CAUTION: Be sure the insulated jumper wire is
dressed so the it does not touch components or sharp
edges.
http://www.wjel.net