Exercises: Assembly and troubleshooting

The image shows the interior of a desktop computer with five numbered components.

Explain in one sentence what task each of the five indicated components performs and describe how they are connected to each other.

These are the steps to set up a new desktop computer, but they are out of order: (a) connect the monitor to the computer tower, (b) connect the keyboard and mouse, (c) plug in the power cables for the monitor and tower, (d) press the power button. Put them in the correct order and explain why it is advisable to plug in the power supply towards the end.

Match each cable with its function in the computer: (a) power cable, (b) HDMI cable, (c) USB cable, (d) network cable. Functions: 1. carries the image from the tower to the monitor; 2. powers the equipment with electricity; 3. connects peripherals such as the keyboard or external storage; 4. connects the computer to the router via cable.

State whether each part goes inside or outside the computer tower: motherboard, keyboard, power supply unit, monitor, RAM, and speakers. Explain the criteria you followed.

Explain in your own words what a USB port is and name three different things you could connect, one at a time, to the same USB port on the computer.

When a computer fails, before asking for help it is useful to observe and note down several things. Make a list of four useful pieces of information for the technician (lights that turn on, sounds or beeps, messages on screen, how long it has been happening...) and explain how each one helps them.

These are the steps to connect a new printer, but they are out of order: (a) install the driver if the computer prompts you to, (b) plug the printer into the power supply, (c) connect the USB cable or link it to the home Wi-Fi, (d) print a test page. Put them in order and explain what the last step is for.

Computer connectors have different shapes (USB, HDMI, network, power...) and each cable 'only fits' into its correct slot. Explain the advantage of this when assembling or repairing a computer, especially if you are a beginner.

The computer turns on (fans can be heard and the tower light turns on), but the screen remains completely black. Propose two possible causes related to the cables or the monitor and explain how you would test each one without opening the tower.

A computer suddenly turns off shortly after being switched on, and the case is very hot. Which component would you check first? Explain the connection between that component, heat and shutdowns, and describe what you would do to confirm your suspicion.

Before opening a computer case, certain safety rules must be followed: switch off the equipment, unplug it from the mains, do not work with wet hands, and touch a metal surface beforehand to discharge static electricity from your body. Explain what risk each rule prevents.

After cleaning the dust from the tower with a blower, the computer does not turn on. Propose the first two things you would check (a cable that came loose from the air, the power button, the power lead...) and justify why these are the first things you would check.

The mouse works in the front USB ports of the tower but not in the rear ones. Propose two possible explanations (a damaged port, a port that only works for certain devices, a driver issue) and write how you would test each one without calling anyone.

Your family wants to move the computer from the living room to the study. Write an ordered list of steps to dismantle, transport and reassemble it without mishaps, including two specific precautions (turn off and unplug beforehand, remember where each cable went, do not drag the tower...).

The power supply unit converts the $220\ \text{V}$ current from the socket into the low voltages used by computer components. Explain what would happen to the computer if the power supply failed and reason why a power supply unit should never be opened, even with the computer unplugged.

For a week, the CPU fan has been making a lot of noise. Analyse three possible causes (dust build-up, worn-out fan, high temperature due to heavy workload) and explain what you would do to check and resolve each one.

In the Technology classroom you plug in a desktop computer and press the power button, but it shows no signs of life: no lights, no fans, no sound. Your classmate says: "The power supply or the motherboard has burned out; let's get screwdrivers and take it apart."

1. a) Refute your classmate's proposal by explaining why opening the case immediately is a bad diagnostic strategy and what unnecessary risks it entails.
2. b) Design a sequential protocol of four checks ordered from lowest to highest complexity and risk that you must perform before touching a single screw, justifying which possible fault you rule out at each step.

You are sizing the components for a school workstation with the following maximum power consumptions: CPU ($65\ \text{W}$), motherboard ($40\ \text{W}$), HDD hard drive ($8\ \text{W}$), two fans ($5\ \text{W}$ each), and a basic graphics card ($75\ \text{W}$). In the workshop, you have two power supplies available: one of $250\ \text{W}$ and another of $500\ \text{W}$.

1. a) A student states: "It is better to install the $250\ \text{W}$ power supply because, since the computer consumes less than $200\ \text{W}$, we will use much less electricity on the bill than with the $500\ \text{W}$ one." Reason technically whether this statement is true or false, explaining what the actual energy consumption depends on.
2. b) If next school year the graphics card is replaced with a technical design one that consumes $170\ \text{W}$, predict what will happen if the computer keeps the $250\ \text{W}$ power supply when running a demanding task, and justify which power supply you should have installed from the beginning by applying a $25\,\%$ safety margin.

The computer in the Technology classroom takes more than three minutes to boot the operating system and freezes when you open several tabs in the web browser. In addition, the warning "Storage almost full: $2,5\ \text{GB}$ free remaining on the $500\ \text{GB}$ HDD" appears. A technician states: "To make it boot quickly and not crash, we only need to expand the RAM from $4\ \text{GB}$ to $16\ \text{GB}$."

1. a) Critically evaluate the technician's statement: will it really solve the problem of slow boot times and the lack of space? Justify your answer by distinguishing the role of RAM from that of the storage drive.
2. b) Design a comprehensive and balanced improvement proposal (combining hardware and software management) to solve the three observed problems at the lowest possible cost.

During a computer assembly practical session, a group of students takes the following actions:

1. They screw the metal motherboard directly onto the case sheet metal, without using the brass standoffs.

2. They force the processor into the socket even though the small triangular mark did not align with the one on the motherboard.

3. They place the metal heatsink on top of the microprocessor without removing the factory protective plastic or applying thermal paste.

Critically analyze this case:

1. a) Predict the likely consequences and faults that may occur in the components if an attempt is made to turn on the computer after this assembly.
2. b) Justify what the correct assembly order is and explain why it is much safer to assemble the processor, the heatsink, and the RAM on the motherboard on the workbench before placing and fastening it into the case.

A computer turns on normally, but it abruptly shuts down or restarts after about 10 or 15 minutes of continuous use, especially when performing heavy tasks. You observe the following data and symptoms on the computer:

• The processor temperature rises steadily until reaching $98\ ^\circ\text{C}$ just before shutting down.

• The CPU heatsink fan spins very slowly and has a thick layer of lint and dust between its metal fins.

• The RAM and the hard drive are detected without errors by the system.

1. a) Interpret these data: explain what physical phenomenon is occurring in the microprocessor and what internal security mechanism of the motherboard causes the restart.
2. b) Design a tiered maintenance protocol in three phases (from the simplest and most economical intervention to hardware replacement) to permanently solve the problem.

The school has a 7-year-old computer that runs very slowly, and three action proposals need to be evaluated:

• Proposal A: Replace the motherboard, current processor, and RAM for $280\ \text{€}$, but reuse the case, the old power supply, and the mechanical hard drive (HDD).

• Proposal B: Buy a complete new computer for $360\ \text{€}$ with a modern processor, current memory, and fast SSD storage.

• Proposal C: Keep all old components and only install a $500\ \text{GB}$ SSD ($35\ \text{€}$) and reinstall a clean operating system.

1. a) Technically analyze why Proposal A contains a serious "bottleneck" that will cause the computer to continue running slowly when booting up and opening programs, despite having spent $280\ \text{€}$.
2. b) Compare the three options by assessing the economic cost, the actual performance improvement, and the environmental impact due to the generation of electronic waste (e-waste). Justify which is the most sustainable and efficient decision for the school.

During a severe thunderstorm, the electrical power is cut off at the high school. After power is restored, one of the computers does not respond when pressing the power button, and there is a clear burning smell coming from the upper rear grille of the case.

1. a) Justify which computer component has failed, explain its function regarding the current supplied by the mains grid ($230\ \text{V}$ alternating current), and deduce what internal protective device it usually incorporates to prevent the surge from destroying the rest of the components (motherboard, CPU, drive).
2. b) The school is hesitating between protecting the computers with surge-protected power strips ($12\ \text{€}$) or with uninterruptible power supplies (UPS, $80\ \text{€}$). Explain what exclusive function a UPS performs compared to a power strip and give a reasoned justification of which of the two you would install on the school's main server and which on the library's search computers.

In your school's computer room, three different faults reported by students occur:

• Issue 1: The computer tower turns on properly (the fans spin and the front LEDs light up), but the screen stays black showing the message "No video signal".

• Issue 2: The computer runs smoothly, but it does not emit any sound through the headphones. Upon checking the back, the green audio cable is plugged into the pink jack, and in the operating system the speaker is muted.

• Issue 3: When pressing the power button, the tower does not boot the system: it emits a continuous sequence of short beeps from the motherboard and the startup halts.

Without using tools or disassembling internal parts in the first two cases:

1. a) Interpret the most likely cause of each issue.
2. b) Design a step-by-step troubleshooting guide so that a classmate without advanced computer skills can resolve issues 1 and 2, and explain what the motherboard beeps mean in issue 3.