Four service methods that can be used to detect faults in electronics equipment. ( 2 marks)
(1) CIRCUIT TRACING
A. Know/study mode of operation.
B. To find out the fault.
(3) Fault isolating
(4) Observation test method [ 2 marks]
EXPLAIN TWO OF THE METHODS LISTED IN QUESTION ABOVE
(1) CIRCUIT TRACING: are split into two;
(a) Know/study mode of operation – To be able to know the general mode of operation, sequential operation of each point, the regular noise from the machine, normal working temperature and normal range of the regulating or measuring instrument.
(b) To find out the fault – This is always cumbersome, tiring and time wasting doing it physically.
(2) TROUBLESHOOTING: This is a method where by fault is purposely introduce into a system in order to watch the behavior under a faulty condition. It might be by;
(I) removal of part
This method will help in knowing how to Carry out repairs or replacement of bad points. It helps to predict the symptoms and signs of a fault.
(3) FAULT ISOLATING: A fault circuit is disconnected from the rest of the system in order to carry out repair services. If possible other parts may continue to function.
(4) OBSERVATION TEST METHOD: consist of the following;
(a) VISUAL— ( sense of sight): To detect loose live terminal, burnt resistor or blown fuse which are indication of overload, short circuit or earth fault.
(b) TOUCH — feeling: By placing ones finger or palm can make one to know whether there’s a rise in temperature, vibration or humming.
c) SMELL — To enable one to know burnt or overheating.
d) HEARING — sound coming from a machine can enable one to suspect or know the type of fault or an unusual sound/humming.