Project Execution – SS3 Computer Hardware & GSM Repair Lesson Note (Third Term)

Project execution is the stage of your final-year project where you carry out your approved plan at the workbench, either by bringing a dead device back to life or by building a new system. It follows a professional process: prepare your workspace, document the starting point, repair step by step, test the result, and record any failure.

Subject: Computer Hardware and GSM Repair
Class: SS3
Topic: Carrying Out Your Project: From Plan to Reality

You have done your research, written your proposal and received your supervisor’s approval. Now it is time to move from paper to the workbench. Before you start melting solder, follow a professional process so that you do not make mistakes that destroy your hard work. Execution needs cleanliness, patience and logic. Keep your workbench organised, follow your schematic like a map, and never rush. Your final project is a reflection of your professional character.

Behavioural objectives

By the end of the lesson, students should be able to:

• Prepare a safe workspace for a repair project.
• Record the starting condition of a device before opening it.
• Open a device, trace a fault with a schematic and carry out a repair using the correct steps.
• Test a repaired board and device before closing it.
• State what to do when a project does not work.

How do you prepare your workspace?

Before you touch the customer’s phone or the computer motherboard, your “lab” must be ready. A messy desk leads to lost screws and “surprises”. A professional setup has these parts:

• The ESD zone: Always use an anti-static mat. One tiny spark of static from your finger can kill a CPU before you even start the repair.
• Lighting: You cannot fix what you cannot see. Ensure you have a bright desk lamp or a microscope light.
• Tool check: Line up your tools. Do you have your multimeter, DC power supply, soldering iron and tweezers ready?
• Safety first: Wear safety glasses and make sure your room has an open window or a fan to blow away solder fumes.

What should you document before the repair?

A professional technician always documents the starting point. Before you open any screw:

1. Visual check: Take a photo of the device. Does it have scratches? Is the screen already cracked?
2. Initial testing: If the device still powers on, test the basics: camera, WiFi, charging and sound. Write the results in your “Project Diary”.
3. The diagnosis: Use your DC power supply to see the current consumption. Is it a “full short” or “no power”? Record the numbers.

How do you carry out the repair step by step?

This is the heart of your project. Whether you are doing a BGA reballing or jumpering a broken track, follow these steps.

Step 1: Open the device

Go slowly. Many modern phones use strong glue. Use a heat mat or heat gun (set to 80°C to 90°C) to soften the glue. Use plastic tools, not metal, so that you do not scratch the frame.

Step 2: Troubleshoot with schematics

Do not guess which chip is bad. Open your schematic viewer (such as Borneo or DZKJ), then:

• Trace the power line.
• Measure the voltages at “test points”.
• Compare your readings with the schematic. If the schematic says you should see 3.8V but you see 0V, you have found the “leak” in the circuit.

Step 3: Carry out the repair (soldering and hardware)

• Flux is your friend: Always use enough flux to help the solder flow.
• Temperature control: Do not keep the hot air gun on one spot for too long, or the board will “pop”.
• Steady hands: If you feel tired or shaky, take a 5-minute break. Precision requires a calm mind.

How do you test the repair (quality control)?

Once you have replaced the faulty part or fixed the connection, do not close the device yet.

• The bench test: Connect the board to the DC power supply again. Is the “short” gone? Does it pull a normal amount of current now?
• Partial assembly: Put the screen and battery back temporarily. Does it show the logo?
• Full functional test: Check the things you might have disturbed. Does the mic still work? Does the home button click?

What should you do when the project fails?

Sometimes you follow every step and the project still does not work. Do not panic.

• Re-trace your steps: Did you fit a capacitor the wrong way round? Check the polarity.
• Consult your diary: Look at your notes from yesterday. What changed?
• Ask for guidance: Show your supervisor your progress. Sometimes a second pair of eyes sees the tiny solder bridge you missed.
• Document the failure: Even if the project does not work perfectly, explaining why it failed in your report can still earn you a good grade.

Evaluation

1. Why is it important to test the camera and WiFi before you start a motherboard repair?
2. What is the danger of using a metal tool to pry open a phone case?
3. Describe what you should do if your hands shake while you try to solder a tiny jumper wire.
4. Why should you record the current reading from the DC power supply during the repair?

Assignment

Prepare a page in your Project Diary for a device you will repair. List the items you would set up in your workspace. Then write the three things you would record before opening the device (visual check, initial testing and diagnosis). Finally, list the three tests you would do before closing the device after the repair.