220-1101 Mobile Device Hardware Servicing — 15 Questions

Question 1

A customer brings in a smartphone with a broken charging port. They want the port replaced. During disassembly, the technician finds that the charging port is soldered directly to the main board. Which tool is essential for this repair?

Accepted Answer

A soldering iron with a fine tip.. A soldered charging port requires desoldering to remove it and reflow soldering to install the new one. A soldering iron with a fine tip is necessary for this precision work. Using a heat gun alone could damage nearby components.

Answer

A heat gun with a narrow nozzle.

Answer

A Phillips-head screwdriver.

Answer

A plastic spudger.

Question 2

A technician is upgrading the RAM in a laptop. After installing two new 8GB sticks, the laptop fails to boot and emits a series of beeps. What is the most likely cause?

Accepted Answer

The RAM modules are not fully seated in the slots.. Beep codes usually indicate a memory error. The most common cause is improperly seated RAM modules. Even if the modules are compatible, they must be fully inserted and locked into place. Reseating the RAM often resolves the issue.

Answer

The RAM is not compatible with the motherboard.

Answer

The laptop's BIOS needs to be updated.

Answer

The RAM was installed in the wrong orientation.

Question 3

A customer reports that their laptop's touchpad is unresponsive after they spilled a small amount of liquid on the keyboard. The laptop still powers on and the keyboard works. What is the most likely issue?

Accepted Answer

The touchpad ribbon cable is damaged or disconnected.. The touchpad is likely disconnected or shorted due to liquid ingress, even though the keyboard still works. In many laptops, the touchpad connects via a separate ribbon cable that can be damaged by liquid. The first step should be to inspect and reseat or replace the touchpad cable.

Answer

The touchpad driver is corrupted.

Answer

The battery is swollen and pressing on the touchpad.

Answer

The touchpad is disabled in the BIOS.

Question 4

A technician is replacing a cracked screen on a smartphone. After removing the old screen, they notice a small, flat, rectangular component with a metal shield is loose near the battery connector. What should they do?

Accepted Answer

Reattach it using double-sided adhesive tape.. The loose component is likely the vibrator motor, which is often a small rectangular module that can become dislodged during disassembly. It should be securely reattached to prevent rattling and ensure proper vibration function. Ignoring it could lead to customer complaints about missing vibration alerts.

Answer

Discard it as it is not needed for the screen replacement.

Answer

Solder it back onto the motherboard.

Answer

Leave it loose; it will not affect screen operation.

Question 5

A technician is installing a new SSD into a customer's laptop. After removing the bottom cover, they see the existing hard drive is held in place by a metal bracket and a single screw. What is the correct next step?

Accepted Answer

Remove the screw and bracket, then gently lift the drive out of the SATA connector.. Removing the bracket and screw allows the drive to be lifted or slid out of its connector. This is standard procedure for 2.5-inch drives in laptops. The technician must also disconnect any attached cables before removal.

Answer

Pull the drive straight out with force to disconnect it.

Answer

Use a plastic spudger to pry the drive from the connector.

Answer

Remove the battery first to avoid electrical shock.

Question 6

A user reports that their laptop's keyboard types random characters when certain keys are pressed. The laptop has not been dropped or spilled on. What is the most likely hardware issue?

Accepted Answer

The keyboard has an internal short or faulty controller.. A faulty keyboard controller or a short in the keyboard matrix can cause random character output. This is a hardware failure within the keyboard assembly. Replacing the keyboard is the standard fix, as individual key repairs are not practical.

Answer

The keyboard driver is corrupted.

Answer

The keyboard ribbon cable is loose.

Answer

The operating system has a malware infection.

Question 7

A technician is troubleshooting a laptop that shuts down randomly after a few minutes of use. The fan is spinning, and the vents are clear. The CPU temperature reaches 95°C quickly. What is the most likely cause?

Accepted Answer

The thermal paste between the CPU and heatsink has dried out.. High CPU temperature despite a spinning fan indicates poor thermal transfer, often due to dried-out thermal paste or a heatsink that is not making proper contact. Reapplying thermal paste and reseating the heatsink is the solution. The fan working rules out a fan failure.

Answer

The fan is running at low speed due to a faulty fan controller.

Answer

The CPU is faulty and needs replacement.

Answer

The BIOS is set to an aggressive power-saving mode.

Question 8

A user complains that their tablet's battery drains very quickly, even when not in use. The device is one year old and was working normally until last week. Which hardware component is most likely failing?

Accepted Answer

The battery has degraded or is failing.. A lithium-ion battery that drains quickly, especially when idle, often indicates the battery has degraded or developed an internal short. Batteries have a finite lifespan and can fail after a year of use. Replacing the battery is the standard fix.

Answer

The charging port is loose.

Answer

The power management IC is faulty.

Answer

The screen brightness is set too high.

Question 9

A technician is repairing a tablet that has a cracked digitizer. The LCD panel is intact and displays correctly. After replacing the digitizer, the touch input is unresponsive. What is the most likely oversight?

Accepted Answer

The digitizer flex cable is not fully seated in the connector.. The digitizer connects via a separate flex cable that must be properly seated. If the LCD works but touch does not, the digitizer cable is likely not fully inserted or the connector is damaged. This is a common error during digitizer-only replacements.

Answer

The digitizer is not compatible with the tablet model.

Answer

The LCD panel was damaged during the repair.

Answer

The tablet's touch controller needs to be calibrated.

Question 10

A technician is troubleshooting a laptop that will not charge. The battery is removable, and the power adapter works on another laptop. When the battery is inserted, the laptop powers on but shows '0% available (plugged in, not charging)'. What is the most likely cause?

Accepted Answer

The battery is defective and needs replacement.. The 'plugged in, not charging' message often indicates a failed battery that cannot accept a charge, even though the system detects it. A defective battery cell will prevent charging. The power adapter and charging circuit are likely fine since the laptop powers on.

Answer

The charging port is loose.

Answer

The power management driver is outdated.

Answer

The CMOS battery is dead.

Question 11

A user reports that their tablet's screen is completely black but the device vibrates when powered on. You have already tried a forced restart and checked for physical damage. What is the most likely hardware cause?

Accepted Answer

The LCD panel or display ribbon cable is faulty.. This question tests diagnosis of a no-display condition with power-on indication. Vibration confirms the device is booting, so the issue is likely with the display assembly or its connection. A failed LCD panel or a loose display cable is the most probable cause, as the backlight or digitizer failure would still show some light or touch response.

Answer

The battery is completely drained.

Answer

The digitizer is cracked.

Answer

The OS is corrupted.

Question 12

During a repair, you accidentally dislodged a small ribbon cable connecting the volume button flex to the mainboard of a smartphone. Now the volume buttons don't work. What is the most likely result of this mistake?

Accepted Answer

The volume buttons become unresponsive.. This question tests knowledge of flex cable connections. The volume button flex cable is a separate component that connects to the mainboard via a ZIF or latch connector. If dislodged, the buttons lose electrical connection and become non-functional, but other features remain unaffected.

Answer

The phone won't power on.

Answer

The touchscreen becomes unresponsive.

Answer

The speaker stops producing sound.

Question 13

A technician is troubleshooting a tablet that has a dim display that flickers intermittently. The device responds to touch and the OS loads normally. Which component is most likely failing?

Accepted Answer

The backlight LED or inverter is failing.. This question differentiates between LCD and backlight failures. A dim, flickering display with normal touch and OS function points to a backlight issue, often caused by a failing LED driver or inverter. The LCD panel itself may be fine.

Answer

The digitizer is malfunctioning.

Answer

The LCD panel has dead pixels.

Answer

The motherboard GPU is damaged.

Question 14

A user reports that their laptop battery no longer charges and the system only runs when plugged in. You test the AC adapter and it outputs correct voltage. Inside the battery, which component is most likely failed?

Accepted Answer

The battery management system (BMS) is faulty.. This question covers battery charging circuitry. The battery management system (BMS) controls charging and communicates with the laptop. If the BMS fails, the battery may not accept a charge even if cells are good. The AC adapter is verified working, so the issue is inside the battery.

Answer

The lithium-ion cells have degraded.

Answer

The DC jack on the laptop is loose.

Answer

The laptop's motherboard charging circuit is damaged.

Question 15

A laptop's touchpad is not working correctly; the cursor jumps erratically. You have already updated the driver and checked for debris. What hardware component should you inspect or replace next?

Accepted Answer

Reseat the touchpad ribbon cable on the motherboard.. This question tests systematic troubleshooting of input devices. After ruling out software and debris, the next step is to check the touchpad's ribbon cable connection to the motherboard. A loose or damaged cable can cause erratic behavior. Replacing the touchpad itself is a later step.

Answer

Replace the entire keyboard assembly.

Answer

Replace the laptop's LCD screen.

Answer

Reinstall the operating system.