THIRD TERM LESSON NOTE FOR WEEK TWO
CLASS : JSS 3
SUBJECT : BASIC TECHNOLOGY
TOPIC : FAULT DETECTIONS
DURATION : 80 MINUTES
PERIOD : DOUBLE PERIODS
REFERENCE BOOK :
BASIC TECHNOLOGY FOR JUNIOR SECONDARY SCHOOL, JSS 3
SCHEME OF WORK FOR JUNIOR SECONDARY SCHOOL (JSS 1 – 3)
ONLINE RESOURCES
LEARNING OBJECTIVES : BY THE END OF THE LESSON LEARNERS WILL BE ABLE TO :
i. Explain Fault Detection and Trouble shooting
ii. Identify the fault Detection aids and state their uses.
iii. Explains the processes of rectifying fault.
CONTENT :
MEANING OF FAULT DETECTION :
Fault detection is a form of maintenance for electronic equipment. Fault detection means isolations the source of a fault and replacing the fault through a processing by eliminating the faulty.
Fault detection is as a process of finding likely fault in electronics by using appropriate maintenance tools.
Therefore, Fault detection can be define as a means to isolate the source of a problem and fixing it through the process of elimination.
Trouble Shooting can be define as a task in locating fault in electronic system or it can also be called Fault Diagnosis.
THE FAULT DETECTION AIDS.
The fault detection aids are:
1. Maintenance manual
2. Fault location guides
3. Test instruments
4. Specialized tools
MAINTENANCE ERROR.
If the fault in any equipment is not properly detected, it may lead to maintenance error. That is repairing and replacing parts of the equipment that is not faulty. Above all it may leads to more damage of the equipment.
PROCESS OF RECTIFYING FAULT IN EQUIPMENT.
The process of rectifying fault in any equipment should pass through the following stages:
1. Fault Detection Stage: this is the first step in fault detection to establish the presence of fault and all the signs accurately noted. This is because equipment may be reported faulty while in fact the failures are caused by incorrect information.
2. Fault Location Stage: After establishing the presence of a fault in equipment, the next step is to locate area of the fault. The fault detection aids are very much used in this stage by technicians in order to verify, to locate and to repair faults.
3. Rectification stage: this is the process of rectifying or replacing a fault in equipment after detecting it and locating it.
Fault detection is also known as corrective maintenance for repairing; replacing parts of the equipment before it finally break down.
FAULT DETECTION INSTRUMENTS
The fault detection tools are used by technicians:
i. To verify
ii. To locate
iii. To repair fault
The tools used as fault detectors instrument varies from device to in electronics. Every electronic component may be checked with the use of electronic meter for fault detection.
The fault detection instrument may include:
1. Hand-held Tester: This is used to detect the presence of electric current at the point of contact.
2. Multi-meter: The electronics and computer technicians always work with multi-meter which is capable of measuring of measuring the resistance, voltage across the components and the current.
3. Dust blower: this is used to remove dust from the surface of an electronic circuit panel. The dust blower is normally connected to the A.C mains.
4. Screw-driver: The star screw drivers and the flat screw drivers are to remove the cover at the back of electronics appliances and also used to remove the screws that hold down the electronic panels.
Soldering Iron: This is a tool with a point that is heated for melting and supplying a soft solder (an alloy of tin and lead) used to join electronic components to a circuit board or for joining metal surfaces together.
5. Oscilloscope: This is one of the most widely used electronic instruments. It allows signal voltage to be viewed in two dimensional views. All oscilloscopes make use of cathode-ray tube, as their display element and linear amplifier for signal processing.
Approach to Fault Detection.
The approach to fault detection include:
1. The technician must know where the components are looped on the circuit.
2. The technician must know what voltage that should be expected at various points on the circuit.
3. The technician must know the kind of features that exist in the circuit.
4. The technician must know how the components are actually connected together.
5. The technician must know how the circuit should function.
EVALUATION :
1. Explain the following :
i. Fault Detection ii. Trouble Shooting
2. Another name for fault Detection in an electronic device is ____________________
3. Mention the Fault Detection instruments.
4. State the three functions of Fault Detection tools.
ASSIGNMENT :
1. Mention the approach to fault Detection.