Computer Assembly and Maintenance Honor

Vocational Activities

Requirements

1. What tools are needed for the assembly and maintenance of computers?

   Answer: You need Phillips and flathead screwdrivers of various sizes, an antistatic wrist strap for electrostatic discharge, needle-nose pliers, an antistatic brush and thermal paste for the processor. — ABNT's NBR 16384 standard recommends the mandatory use of an antistatic wrist strap in the maintenance of sensitive electronic equipment to prevent discharges that damage components.

2. What is a test card?

   Answer: You use a test card (also called a POST card or debug card) inserted into a PCI or PCIe slot of the motherboard to diagnose boot problems. — POST cards became popular with the IBM PC standard in the 1980s, and their codes follow standards defined by AMI, Award and Phoenix, the main BIOS manufacturers.

3. What precautions are necessary when handling the internal components of computers?

   Answer: You need to turn off and unplug the equipment from the outlet before opening it, use an antistatic wrist strap attached to the metal case, hold components by the edges avoiding contact with circuits and chips, and work on a clean, dry and antistatic surface. — An imperceptible human electrostatic discharge can reach 25,000 volts, enough to damage sensitive circuits from as little as 100 V, according to the ANSI/ESD S20.20 standard.

4. What is static electricity? What risks does it pose? How can you prevent it from damaging the computer's components?

   Answer: Static energy (static electricity) is the buildup of electrical charges on surfaces and on the human body, usually from friction; when you touch a component, it discharges in the form of an electrostatic discharge (ESD) of hundreds to thousands of volts. RISKS: this discharge, even when imperceptible, damages or burns sensitive components (processor, memory, motherboard chips), causing immediate or intermittent defects that reduce the hardware's lifespan. HOW TO AVOID IT: 1) use an antistatic wrist strap attached to the grounded metal case; 2) discharge your body by touching a grounded metal part before handling parts; 3) work on an antistatic mat/surface; 4) hold components by the edges, without touching traces and contacts; 5) keep parts in their antistatic packaging until installation; 6) avoid very dry environments and clothing/footwear that generate friction. — The IEC 61340-5-1 standard establishes static electricity control in electronics manufacturing, requiring a minimum relative humidity of 30% and conductive footwear in critical areas.

5. Define what it is, and what processes it carries out:
   • BIOS;
   • POST;
   • Boot.

   Answer: 1) BIOS (Basic Input/Output System): it is the firmware stored on a memory chip of the motherboard. Processes it carries out: it initializes and configures the basic hardware when the computer is turned on, identifies and tests the components, stores system settings (date, time, boot order) and bridges the hardware and the operating system, handing control to the boot loader. 2) POST (Power-On Self-Test): it is the startup self-test run by the BIOS as soon as the computer is turned on. Processes it carries out: it checks the essential components (processor, RAM, video card, keyboard and other devices); if everything is correct, it emits a short beep and allows the boot to continue; if it finds a fault, it signals it by means of beeps or error codes, interrupting the process. 3) BOOT: it is the process of loading and starting up the operating system. Processes it carries out: after the BIOS completes the POST, it locates the defined boot device (HD, SSD, flash drive, etc.), loads the boot manager/loader and transfers control to the operating system, leaving the computer ready for use. — The BIOS was created by Gary Kildall in 1975 for the CP/M system and standardized by IBM in 1981, being gradually replaced by the UEFI standard starting in 2007.

6. Why is the motherboard considered the heart of the computer and the processor, the brain?

   Answer: The motherboard is the 'heart' because it interconnects and integrates all the components (processor, memory, storage, GPU, peripherals), distributing power and circulating the data between them through the buses — just as the heart pumps blood throughout the body. The processor (CPU) is the 'brain' because it is where the processing actually happens: it executes the instructions, performs the arithmetic and logical calculations and commands/controls all the operations of the system, making the decisions that coordinate the functioning of the computer. — The first commercial microprocessor was the Intel 4004, launched in 1971 with 2,300 transistors, and modern processors such as the AMD Ryzen 9 already reach more than 13 billion transistors.

7. With a live motherboard or through a photograph, identify and indicate the function of:
   • Processor socket;
   • Memory socket, and state the type;
   • Power supply connector;
   • Slots present, and state the type of bus;
   • Chipsets;
   • IDE and/or SATA interface;
   • Case connectors for the front panel, audio, USB.

   Answer: You identify the chipsets as controllers that manage communication between the processor, memory, expansion slots and peripherals. — Intel introduced the PCH concept in 2008 with the Nehalem platform, integrating northbridge functions into the processor itself and simplifying the motherboard layout.

8. Indicate which models of RAM memory module (DDR2, DDR3, etc.) are most used today and which have the greatest potential capacity?

   Answer: DDR4 is still the most common in computers in use, but DDR5 (released in 2021) is the current standard in new PCs, offering greater bandwidth and capacity. — JEDEC ratified the DDR5 standard in July 2020, doubling the base speed from 3,200 MT/s to 6,400 MT/s compared to DDR4, with voltage reduced from 1.2 V to 1.1 V.

9. Explain the relationship of using high-capacity memory in low-performance computers.

   Answer: You understand that a slow processor, a mechanical disk and a limited bus create bottlenecks before the memory is fully utilized. — Studies by Crucial show that RAM upgrades bring a real gain only if the memory usage was above 80% before the expansion; in systems with a limited CPU, the gain is marginal.

10. On the HDD, what are tracks, sectors, cylinders, clusters and bad blocks?

    Answer: 1) TRACKS: concentric circles recorded on the surface of each HDD platter, where the data is stored. 2) SECTORS: the smallest divisions of a track (slices of the circle), the physical unit of recording, with 512 bytes (old format) or 4096 bytes (Advanced Format). 3) CYLINDERS: the set of all tracks of the same position (same radius) stacked vertically across all platters; the read head accesses all of them without moving. 4) CLUSTER (allocation unit): a logical grouping of several sectors that the file system uses as the smallest unit for recording a file. 5) BAD BLOCKS (defective blocks): sectors physically or logically damaged that can no longer store data reliably and are marked by the system so that they are not used. — The CHS (Cylinder-Head-Sector) concept was created by IBM in the 1950s and dominated until the 1990s, being replaced by LBA (Logical Block Addressing) addressing in modern disks.

11. What are (storage) file systems? Name at least three and tell the main differences between them.

    Answer: You cite NTFS (Windows, support for permissions and large files, journaling), FAT32 (compatible with various systems, but a 4 GB limit per file) and EXT4 (Linux, robust journaling and support for very large partitions). — NTFS was introduced by Microsoft in 1993 with Windows NT 3.1, offering advanced features such as ACL permissions and EFS encryption, absent in FAT32.

12. What are the main differences between AT and ATX cases?

    Answer: AT case/standard (prior to 1995): a power supply with a physical switch (toggle) for on/off, a power connector in two pieces (P8/P9) that connect to the motherboard (with the risk of reversing them), a keyboard with a large DIN connector, a larger motherboard with a layout that hindered cooling. ATX case/standard (from 1995, dominant today): a power supply with a single 20/24-pin connector (a single fit, with no risk of reversing), software shutdown (soft-off, the motherboard controls the power supply and can turn it on via keyboard/network), integrated PS/2 keyboard/mouse and USB connectors on a standardized rear panel, better positioning of the CPU and memory near the power supply's ventilation, improving airflow and cooling. — The ATX standard was created by Intel in 1995 and became the reference for cases and power supplies in home PCs, gradually replacing IBM's old AT from the 1980s.

13. What is the CPU?

    Answer: You recognize the CPU as an integrated circuit that executes instructions, performs arithmetic and logical calculations, and controls all the operations of the system, defining much of the computer's performance. — The first single-chip CPU was the Intel 4004, launched in 1971 with 740 kHz and 4 bits, against today's multi-core processors with 5+ GHz and 64-bit architecture, the basis of all modern computing.

14. What is the processor's clock?

    Answer: You understand the clock as the frequency at which the processor executes instructions, measured in hertz (usually GHz). — The Intel 4004 ran at 740 kHz in 1971; the current overclocking record is 9.12 GHz by the AMD FX-8350, achieved with liquid nitrogen in 2014.

15. What are Hertz and how are they calculated?

    Answer: Hertz (Hz) is the unit of frequency of the International System, defined as one cycle per second. — The hertz unit was named in honor of the German physicist Heinrich Hertz, who proved in 1887 the existence of the electromagnetic waves predicted by James Maxwell.

16. Cite at least five factors that define the capacity of the processor.

    Answer: You list the clock frequency (GHz), the number of cores and threads, the size of the cache (L1, L2, L3), the internal architecture and IPC (instructions per cycle) and the manufacturing process (in nanometers). — Apple M3 processors, manufactured at 3 nm by TSMC since 2023, demonstrate that an advanced manufacturing process can deliver more performance with lower consumption, complementing clock and cores.

17. What advantages were gained in the change of components from the parallel bus (PATA) to the serial bus (SATA)?

    Answer: SATA brings thin cables that improve airflow, hot-swap support, speeds of up to 6 Gbps on SATA III versus 133 MB/s on PATA, NCQ and a point-to-point connection without master/slave jumpers. — The first SATA specification was released in 2001 by SATA-IO at 1.5 Gbps; SATA III, from 2009, reaches 6 Gbps with 8b/10b encoding, dominating the storage market ever since, globally.

18. Explain what the setup screen is, how to access it and what the main functions within the assembly and maintenance area are.

    Answer: WHAT IT IS: the Setup screen is the configuration interface of the motherboard's firmware (BIOS/UEFI), stored on a chip and powered by the CMOS battery, where the computer's hardware parameters are adjusted. HOW TO ACCESS: press the indicated key right after turning on the computer, during the POST — usually Delete, F2, F10, Esc or F12 (varies by manufacturer). MAIN FUNCTIONS useful in assembly and maintenance: set the boot order (HDD, SSD, USB, network); view/check recognized hardware (CPU, RAM, disks) and temperatures/voltages; adjust the system date and time; enable/disable onboard devices (network, audio, USB, integrated video); configure the SATA mode (AHCI/RAID); enable virtualization (VT-x/AMD-V); adjust memory profiles (XMP) and, with caution, frequencies/overclock; set the access password and security options (Secure Boot); restore default settings (load defaults) and save/exit. — The UEFI standard replaced the legacy BIOS from 2005 on, with support for disks larger than 2 TB, a graphical interface and Secure Boot, according to the specifications of the UEFI Forum.

19. Demonstrate the following:
    • Disassemble and assemble a computer, identifying each internal component, stating its function and handling it properly;
    • Make correct use of thermal paste and explain its function;
    • Connect an off-board card and run it, showing the performance improvement in that area;
    • Format a computer;
    • Partition the formatted storage disk into three partitions;
    • Install an operating system on the formatted storage disk, configure it and make it ready for use;
    • Combine (merge) two of the three partitions;
    • List the importance of each one and then install all the basic programs needed for the home use of a computer.

    Answer: You apply thermal paste to fill the micro-irregularities between the surfaces of the processor and the cooler, improving heat transfer. — Modern thermal pastes such as the Arctic MX-6 reach a thermal conductivity of 8.5 W/mK, being up to 50% more efficient than traditional economy silicone-based pastes.

20. Explain how to prevent, diagnose and/or correct the following problems:
    • Dirty memory card;
    • Processor overheating;
    • Computer with no audio;
    • Does not get past the "black screen";
    • Restarts repeatedly;
    • Virus.

    Answer: 1) Dirty memory module: oxidized or dusty contacts cause a startup failure (the machine does not turn on or beeps). Prevent it by keeping the case closed and clean; diagnose it by removing the memory and checking whether the contacts are dark; fix it by cleaning the gold traces with a soft white eraser or isopropyl alcohol, drying well and reseating it firmly until it locks. 2) Processor overheating: freezes, sudden shutdowns and slowness indicate overheating. Prevent it with good ventilation and periodic cleaning; diagnose it with temperature software or by a very noisy/hot cooler; fix it by cleaning the heatsink and the fans and renewing the thermal paste between the processor and the cooler. 3) Computer with no audio: first check whether the volume is not muted and whether the cable is in the correct output (green). Diagnose it by testing another headphone/speaker; fix it by reinstalling or updating the sound driver and checking the default playback device in the system. 4) Does not get past the "black screen": this can be a loose video cable, badly seated memory or a failure in the monitor/video card. Diagnose it by testing with another monitor/cable and reseating the memory; fix it by refastening the memory modules, replacing the suspect video cable and testing the video card in another slot. 5) Reboots repeatedly: usually a weak/defective power supply, overheating or a system error. Diagnose it by testing the power supply with a multimeter and watching the temperature; fix it by replacing the power supply or the suspect cables, cleaning the coolers and, if it is software, restoring or reinstalling the system. 6) Virus: causes slowness, ads, freezes and files disappearing/corrupting. Prevent it with an updated antivirus and by avoiding suspicious downloads and flash drives; diagnose it with a full scan; fix it by quarantining/removing the files with the antivirus and, in a severe infection, formatting and reinstalling the system. — CompuRepair statistics indicate that about 35% of unexpected reboots are caused by thermal failures, 25% by degraded power supplies and 20% by defective RAM.