Page 46 - Testing Electronic Components
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Failure among variable resistors usually takes form of intermittent
connections between the wiper blade and resistive film. Sometimes it also
can be burnt due to overload of currents and develop an open circuit.
Remember that film slowly wears away as the wiper moves back and
forth across it. After sometimes the overall film can wear away that
which the wiper cannot make a good contact at certain points. The poor
contact can cause all types of erratic or intermittent operation.
If the intermittent connections are due to dust and debris, using an
electronic oil-based contact cleaner may help to solve the problem. But,
if the problems are caused by the wearing away of the resistive film, the
only option is to replace the variable resistors.
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