Replacing Components on the Circuit Boards
3. When the lead comes out of the board it should leave
a clean hole. If not, the hole should be cleaned by reheating
It is best to remove the circuit board assembly to replace
the solder and placing a sharp object such as a wooden
components, because melted solder at the connections will
toothpick or enameled wire into the hole to remove the old
wick through the plated eyelets and can produce electrical
solder.
shorts. If the component is replaced without removing the
4. Clean the leads on the new component and bend them
board make certain an electrical short does not exist.
to the correct shape to fit into the holes. Insert the leads,
Use electronic grade 60/40 solder and a 15-watt pencil
making certain the component seats the same as the original,
5. Apply the iron to the connection at the back of the
soldering iron tip should be clean and properly tinned for
board and apply only the amount of solder required to form
maximum heat transfer. Higher wattage irons may damage
a good electrical connection.
the bond between the etched wiring and the base material.
6. Check the front or component side of the board to
The following technique is suggested in the replacement
insure that the solder has filled the plated eyelet.
of a component on the circuit board assembly:
1. Remove the component by cutting the leads near the
NOTE
body. This frees the leads for individual unsoldering,
Some components can be damaged by heat. A
2. Grip the lead with needle-nose pliers. Apply the tip
hemostat or forceps, between the component and
of the soldering iron to the connection at the back of the
the connection will protect the component from
board, then pull gently to remove the lead.
excessive heat.
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