Elenco DataCom Tester Kit - Manual (Page 5)

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A poorly soldered joint can greatly affect small current flow in circuits and can cause equipment failure. You can damage
a PC board or a component with too much heat or cause a cold solder joint with insufficient heat. Sloppy soldering can
cause bridges between two adjacent foils preventing the circuit from functioning.
TROUBLESHOOTING
1. One of the most frequently occurring problems is poor
solder connections.
a) Tug slightly on all parts to make sure that they
are indeed soldered.
b) All solder connections should be shiny.
Resolder any that are not.
c) Solder should flow into a smooth puddle rather
than a round ball. Resolder any connection that
has formed into a ball.
d) Have any solder bridges formed? A solder
bridge may occur if you accidentally touch an
adjacent foil by using too much solder or by
dragging the soldering iron across adjacent foils.
Break the bridge with your soldering iron.
Solder
Soldering Iron
Foil
Solder
Soldering Iron
Foil
Component Lead
Soldering Iron
Circuit Board
Foil
Rosin
Soldering iron positioned
incorrectly.
Solder
Gap
Component Lead
Solder
Soldering Iron
Drag Foil
1. Solder all components from the
copper foil side only. Push the
soldering iron tip against both the
lead and the circuit board foil.
2. Apply a small amount of solder to
the iron tip. This allows the heat
to leave the iron and onto the foil.
Immediately apply solder to the
opposite side of the connection,
away from the iron. Allow the
heated component and the circuit
foil to melt the solder.
1. Insufficient heat - the solder will
not flow onto the lead as shown.
3. Allow the solder to flow around
the connection. Then, remove
the solder and the iron and let the
connection cool. The solder
should have flowed smoothly and
not lump around the wire lead.
4. Here is what a good solder
connection looks like.
2. Insufficient solder - let the
solder flow over the connection
until it is covered.
Use just enough solder to cover
the connection.
3. Excessive solder - could make
connections that you did not
intend to between adjacent foil
areas or terminals.
4. Solder bridges - occur when
solder runs between circuit paths
and creates a short circuit. This is
usually caused by using too
much solder.
To correct this, simply drag your
soldering iron across the solder
bridge as shown.
What Good Soldering Looks Like
A good solder connection should be bright, shiny, smooth, and uniformly
flowed over all surfaces.
Types of Poor Soldering Connections