User manual

Figure 21: De-soldering pump (order no.: 588502-62) to remove excessive solder
3.4 Too Hot and too Cold Solder Points
Perfect soldering can be recognised by its nice gloss. A cold soldering point looks some-
what matte and often has a lumpy surface. Defective solder points can also be recognised
if the small solder cone around the component connection is missing or hardly there. Cold
solder points have only low mechanical resistance. If you jiggle a component a little, the
connections within the solder cone may come loose, and it will only loosely be stuck in it.
Cold solder points occur if you did not sufficiently heat the solder point and solder. This
may happen if soldering is done very fast or if the soldering iron does not provide enough
power for larger soldering work. Cold solder points will break open even at very small vi-
brations.
Bad solder points may also result from high temperatures. The high soldering temperature
will cause faster oxidation of the components to be connected. A typical sign for the sol-
der temperature being too high is also so-called
whisker-formation . Whiskers are solder
residue that stands out of the solder point like thin protrusions and that may cause short
circuit.
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