Repairing faulty components is a core responsibility of an ICT Technician in Kenya, requiring a deep understanding of hardware parts and the correct procedures for replacement. The ability to select appropriate replacement components and assemble the necessary tools ensures efficient service delivery and minimizes downtime for clients. This chapter focuses on the practical aspects of identifying faulty hardware and preparing for effective repair or replacement tasks within diverse Kenyan workplaces such as schools, banks, and county government offices.

2.1 Selection of computer components for replacement

Selecting the right computer components for replacement is critical to restoring the device's functionality without compromising performance or compatibility. ICT technicians often work with a variety of brands and models, so knowledge of hardware standards and specifications is essential. This topic covers the hardware components found in a computer, the factors that guide the choice of a replacement, and the way parts are acquired, so that the repair is reliable and long lasting.

2.1.1 Computer hardware components

Computer hardware components are the physical parts that make up a desktop, laptop or workstation. Each part has a specific function, and a fault in one part often shows up as a symptom somewhere else, for example a failing power supply causing random restarts. A technician in a repair workshop must recognise each component, know what it does and know which specifications identify it before ordering a replacement.

Main hardware components found in a computer:

• Motherboard: The main circuit board that connects all other components. It determines the processor socket, memory type, storage interfaces and the physical size (form factor) of the system.
• Central processing unit (CPU): The processor that executes instructions. It must match the socket and chipset of the motherboard.
• Random access memory (RAM): Temporary working memory. Desktops use full-size DIMM modules, while laptops usually use smaller SO-DIMM modules, and the generation (for example DDR4) must match the board.
• Storage devices: Hard disk drives (HDD) and solid-state drives (SSD) hold the operating system and data. They connect through interfaces such as SATA or NVMe.
• Power supply unit (PSU): Converts mains alternating current into the lower direct-current voltages used by the components. Its wattage and connectors must suit the system.
• Cooling system: Heatsinks and fans remove heat from the CPU, graphics chip and PSU. A failed fan can cause overheating, shutdowns and damage to other parts.
• Display unit: A monitor or a laptop screen that shows output. Laptop screens differ in size, resolution and connector type, so the exact model must be matched.
• Input devices: Keyboards, mice and touchpads allow the user to enter data. They connect by USB, wireless link or an internal ribbon cable.
• Expansion cards and network adapters: Graphics cards, sound cards and network cards add or improve functions and must fit the available slots.

2.1.1.1 Factors to consider in selecting computer components

Before buying a replacement, the technician must confirm that the part will work with the existing system, that it is of acceptable quality and that its cost is justified. Choosing on price alone often leads to repeat repairs, unhappy clients and lost time in the workshop. The factors below are checked in turn for every replacement.

Compatibility factors:

• Form factor matching: Replacement motherboards, power supplies and cases must fit the physical dimensions of the original hardware.
• Interface standards: Components like RAM or hard drives must comply with the system's interface (for example DDR4 RAM, SATA or NVMe storage).
• Power requirements: Replacement power supplies or components should meet or exceed the original's wattage and voltage specifications, and have the correct connectors.
• Firmware and driver support: Ensuring the new component is supported by the system's BIOS and operating system avoids functionality problems after installation.
• Brand and model considerations: Selecting reputable brands with local warranty support ensures component reliability and easier maintenance.

Quality and warranty factors:

• Warranty duration and coverage: Longer warranties with comprehensive coverage provide assurance against early failures.
• Certification standards: Components with CE, FCC or Kenya Bureau of Standards (KEBS) marks show that the part has met safety and performance benchmarks.
• Expected lifespan: Parts with a proven service life, such as a good quality PSU or a drive with a long rated endurance, reduce repeat repairs.
• Customer reviews and feedback: Peer reviews and testimonials from other ICT technicians can guide quality judgments.
• Physical condition: New parts should arrive sealed in original packaging, with no bent pins, scratches, burn marks or missing accessories.

Cost factors:

• Initial purchase price versus durability: Sometimes a higher upfront cost is justified by a longer component lifespan.
• Energy efficiency: Components that consume less power reduce operating expenses over time.
• Compatibility with existing infrastructure: Choosing a part that fits the current system avoids unnecessary upgrades that inflate the total cost.
• Total cost of ownership: This includes the part, labour for installation, maintenance and the likelihood of future repairs, and not only the shelf price.

Example: A client's desktop has a failed power supply. One unit costs Ksh 3,500 with a three-month warranty, and another with the same rated wattage and connectors costs Ksh 4,800 with a twelve-month warranty. For an office that uses the computer daily, the technician may recommend the second unit because the longer warranty and better build reduce the chance of a repeat visit and of damage to the motherboard.

2.1.1.2 Computer hardware components parts acquisition

Parts acquisition is the process of finding, buying and receiving the replacement component once the selection factors have been applied. A careful process protects the technician from counterfeit or wrong parts and keeps the client's downtime short. In a repair workshop, acquisition is recorded so that the part, its supplier and its warranty can be traced if a fault returns.

Common sources of parts:

• Authorised dealers and certified distributors: These supply genuine parts with valid warranties and reduce the risk of counterfeit components.
• Manufacturer or brand service channels: Best for model-specific parts such as laptop screens, keyboards, batteries and motherboards.
• Computer parts retailers and online suppliers: Offer a wide choice, but the seller's reputation, delivery time and return terms must be checked first.
• Refurbished or used parts: Cheaper and sometimes the only option for old models, but they must be tested and carry a short warranty at least.
• Salvaged parts from decommissioned machines: Useful for low-cost repairs, provided the part is tested before and after installation.

Steps in acquiring a replacement part:

1. Confirm the fault by inspection and testing so that only the defective component is replaced.
2. Record the details of the faulty part: brand, model, part number, capacity or wattage, interface and connector type, usually printed on its label.
3. Check compatibility with the rest of the system using the factors in the previous section.
4. Request quotations from at least two suppliers and compare price, warranty, availability and delivery time.
5. Confirm authenticity by buying from an authorised dealer, checking seals, labels and serial numbers, and asking for a receipt or invoice.
6. Agree the return and replacement policy before paying, so that a wrong or dead-on-arrival part can be exchanged quickly.
7. Inspect the part on delivery for damage and compare its label with the order before signing.
8. Record the purchase in the job card, including the supplier, cost, date and warranty period, and keep the receipt for the client.

Other acquisition considerations:

• Availability of local support and spares: Parts from suppliers with accessible maintenance services reduce downtime and repair costs.
• Bulk purchasing benefits: Institutions or workshops that buy several components together, such as RAM modules or SSDs for a computer laboratory, may negotiate better prices.
• Stock holding: Keeping a small stock of commonly needed items such as RAM, SSDs, CMOS batteries and power cables shortens repair time, but stock tied up in unused parts is a cost.

Identifying faulty hardware components

Identifying faulty hardware requires a systematic approach that combines visual inspection, diagnostic tools and user feedback. Replacing the wrong component wastes money and prolongs downtime, so fault identification comes before selection. In a school computer laboratory, for example, a machine that will not boot could have a failed PSU, faulty RAM or a damaged motherboard, and each needs a different part.

Common symptoms indicating hardware failure:

• System failure to boot: This often signals issues with the motherboard, PSU or RAM, requiring careful diagnosis to pinpoint the defective component.
• Frequent system crashes or blue screens: These can result from faulty RAM, overheating CPUs or failing hard drives, and need targeted testing.
• Unusual noises: Clicking or grinding sounds usually come from hard drives or cooling fans, indicating mechanical failure.
• Peripheral malfunctions: Non-responsive keyboards, mice or display units may point to connection problems or component failure.
• Visual defects: Burn marks, bulging capacitors on motherboards or cracked screens are clear indicators of physical damage needing replacement.

Tools and methods for fault diagnosis:

• POST (Power-On Self-Test) codes: Beep codes during startup help identify motherboard or RAM issues.
• Diagnostic software: Tools like MemTest86 for RAM or CrystalDiskInfo for hard drives assist in detecting hardware faults.
• Multimeter use: Measuring voltages on PSU outputs confirms power stability.
• Visual inspection: Checking for physical damage or dust accumulation that could cause overheating or short circuits.
• User reports: Gathering detailed user feedback on symptoms helps narrow down the fault area.

Chapter Summary

This chapter explored the process of repairing faulty computer components, beginning with the selection of appropriate hardware parts for replacement, considering factors such as compatibility, quality, and availability. It then detailed the essential tools required for computer repair and maintenance, including various types of screwdrivers, tweezers, pliers, wire cutters, chip extractors, and wrenches. The importance of observing safety procedures was emphasized, covering the use of personal protective equipment, fire safety knowledge including classes of fires and extinguishers, emergency protocols, first aid readiness, and contingency planning. The chapter further explained how to utilize instruction manuals during the disassembly, repair, and reassembly of computer components to ensure proper handling and functionality. Finally, it addressed the environmental and health concerns related to disposing of faulty or obsolete computer hardware, highlighting the nature of pollution, types of e-waste, associated hazards, and recommended proper disposal methods to mitigate negative impacts. This comprehensive approach ensures that learners understand both the technical and safety aspects critical to effective computer repair and maintenance.