Carrying out fault location on communication-electronic systems

This standard identifies the competences you need to locate faults on communication-electronic systems, in accordance with approved procedures. You will be required to locate faults on a range of communication-electronic systems, sub- systems, assemblies or components at line replacement unit (LRU) level. You will be expected to use a variety of fault location methods and procedures, such as gathering information from the person who reported the fault, using recognised fault finding techniques and diagnostic aids, measuring, inspecting and operating the system. You will be expected to take care that you do not damage the system during the maintenance activities and, where appropriate, the application of electrostatic discharge (ESD) procedures will be a critical part of your role.

Your responsibilities will require you to comply with organisational policy and procedures for the fault location activities undertaken, and to report any problems with these activities, or with the tools and equipment used, that you cannot personally resolve, or are outside your permitted authority, to the relevant people. You will be expected to work to instructions, alone or in conjunction with others, taking full responsibility for your own actions, and for the quality and accuracy of the work that you carry out.

Your underpinning knowledge will be sufficient to provide a sound basis for your work, and will provide an informed approach to applying fault location procedures on communication-electronic systems. You will have an understanding of the basic fault location methods and techniques used, and their application. You will also know how to interpret the information obtained from diagnostic aids and equipment, in adequate depth to provide a sound basis for carrying out the activities.

You will understand the safety precautions required when carrying out the fault location activities, especially those for isolating the equipment. You will also understand your responsibilities for safety and the importance of taking the necessary safeguards to protect yourself and others in the workplace.

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1. work safely at all times, complying with health and safety and other relevant regulations, directives and guidelines
2. review and use all relevant information on the symptoms and problems associated with the products or assets
3. investigate and establish the most likely causes of the faults
4. select, use and apply diagnostic techniques, tools and aids to locate faults
5. complete the fault diagnosis within the agreed time and inform the appropriate people when this cannot be achieved
6. determine the implications of the fault for other work and for safety considerations
7. use the evidence gained to draw valid conclusions about the nature and probable cause of the fault
8. record details on the extent and location of the faults in an appropriate format

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1. the health and safety requirements of the area in which the fault location is to take place, and the responsibility these requirements place on you
2. the isolation and lock-off procedure or permit-to-work procedure that applies in the work area
3. what constitutes a hazardous voltage and how to recognise victims of electric shock
4. the importance of wearing protective clothing and other appropriate safety equipment (PPE) during fault location activities
5. the hazards associated with carrying out fault location activities on communication electronic equipment (such as live electrical components, stored energy, misuse of tools), and how they can be minimised
6. how to reduce the risks of a phase to earth shock (such as insulated tools, rubber mating and isolating transformers)
7. the procedure to be adopted to establish the background of the fault
8. how to use the various diagnostic aids to help identify the location of the fault
9. the various fault location techniques that can be used, and how they are applied (such as half-split, input-to-output, function testing, unit substitution, and equipment self-diagnostics)
10. how to evaluate sensory information (sight, sound, smell, touch)
11. how to assess evidence and evaluate the possible causes of faults/problems
12. the care, handling and application of electrical test equipment
13. the precautions to be taken to prevent electrostatic discharge (ESD) damage to electronic circuits and components (such as use of wrist straps, special packaging and handling areas)
14. how to use a range of fault diagnostic equipment to investigate the problem
15. how to check that the electronic test equipment is within calibration, and that it is free from damage and defects
16. how to obtain and interpret information from job instructions and other documents needed in the fault location process (such as drawings, circuit and physical layouts, charts, specifications, manufacturers' manuals, history/maintenance reports, graphical electrical symbols, BS7671/IET wiring regulations)
17. the functions of different types of electronic components (analogue or digital), and their operation
18. the problems that can occur during the fault location activity, and how they can be minimised
19. the importance of completing the correct documentation, following the maintenance activity

the extent of your own authority and to whom you should report if you have problems that you cannot resolve

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1. Carry out all of the following during the fault location activity:

   1. plan fault location methods and procedures in conjunction with others
   2. use the correct issue of maintenance documentation (such as drawings, manuals, maintenance records)
   3. adhere to procedures or systems in place for risk assessment, COSHH, personal protective equipment and other relevant safety regulations
   4. ensure the safe isolation of equipment (such as mechanical, electricity, gas, air or fluids)
   5. ensure that safe access and working arrangements has been provided for the maintenance area
   6. use grounded wrist straps and other electrostatic discharge (ESD) precautions, where appropriate
   7. disconnect or isolate components or parts of the circuit to confirm diagnosis, where appropriate
   8. carry out the fault location activities, using approved procedures
   9. identify the fault, and consider appropriate corrective action
   10. in conjunction with others, take actions to resolve the problem
   11. dispose of waste items in a safe and environmentally acceptable manner
   12. leave work area in a safe and tidy condition

2. Carry out fault location on two communication-electronic systems, sub-systems, assemblies or components to LRU level (at least one of which must be selected from group A):
   note: Any of the items below can be identified as a system, sub-system or assembly in its own right

group A - communication electronics

1.  transmitters (such as HF, VHF, UHF, microwave)
2.  transceivers (such as HF, VHF, UHF, microwave)
3.  receivers (such as HF, VHF, UHF, microwave)
4.  signal processing (analogue) (such as radar anti-clutter, comms audio, and AGC stages)
5.  signal processing (digital) (such as digital MTI, multiplexers, AGC)
6.  aerial systems (such as phased arrays, long wire and parabolic reflectors)
7.  transmission lines (such as optical fibres, co-axial, baluns, twin wire, waveguide)
8.  display systems (such as CRT, Plasma, TFT, TV Tab, LED)
9.  man-machine interface (such as IS/ICT equipment or peripherals: keypads, keyboards, microphones)
10.  electro-optical systems (such as cameras, thermal imaging, targeting systems)
11.  hydraulic-electrical systems (such as hydraulic motors, HSUs, and actuators)
12.  cryptographic systems (such as data encryption and de-encryption)
13.  built-in test equipment
14.  data network systems (such as LANs, WANs)
15.  data network interfaces (such as switch, router, bridging networks)
16.  any other identifiable electronic system, sub-system, assemblies or components to LRU level  

group B - associated equipment
17. environmental control systems (such as temperature, humidity, vibration, shock, alarm and protection)
18. electro-mechanical systems (such as servos, motors, relays, complex switches)
19. power generation systems (such as fixed/transportable AC/DC generators, batteries)
20. power distribution systems (such as single phase/3-phase distribution panels)
21. power supply control systems (such as voltage/current, series shunt regulator/stabiliser)
22. hybrid systems (such as ADC, DAC)

3. Use four of the following methods and procedures to assist in locating the fault:

   1. information gathered from the person who reported the fault
   2. fault finding techniques (such as six point, half-split, input/output, unit substitution, emergent sequence, function testing)
   3. diagnostic aids (such as manuals, flow charts, troubleshooting guides, electronic aids, equipment records, software based aids)
   4. inspecting (such as checking for breakages, wear/deterioration, overheating, missing parts, poor joints, incorrect seating)
   5. operating (such as manually switching off and on, test buttons, running equipment)
   6. equipment self-diagnostics

4. Use two of the following types of instruments to assist in locating the faults:

   1. stabilised power supplies
   2. oscilloscope
   3. multimeter
   4. logic probe
   5. current tracer
   6. signal generator
   7. other specific test equipment

5. Locate faults that have resulted in two of the following breakdown categories:

   1. intermittent action or a system failure
   2. partial failure or reduced performance
   3. complete breakdown

6. Complete one of the following maintenance records, and pass it to the appropriate person:

   1. scheduled maintenance report
   2. corrective maintenance report
   3. other company-specific report

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2

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30 Mar 2018

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Current

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Original

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Semta

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SEMEMI2-32

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Maintenance Fitter

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5223

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Engineering; maintenance; fault location; communication; electronic; transmitters; receivers; aerial systems; display systems

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