CMT Device Hardware & Software 2 — Questions and Answers
Question 1: A customer's smartphone charges very slowly even with the original charger. After ruling out the cable, what component should a technician inspect next?
- Battery health and capacity
- Charging port for debris or damage (Correct answer)
- Display brightness settings
- Bluetooth radio antenna
Correct answer: Charging port for debris or damage
A damaged or debris-filled charging port creates resistance that reduces charging current, causing slow charging.
Question 2: Which memory type in a mobile device retains data without power and stores the operating system?
- LPDDR5 RAM
- NAND Flash (eMMC/UFS) (Correct answer)
- SRAM cache
- DRAM
Correct answer: NAND Flash (eMMC/UFS)
NAND Flash (eMMC or UFS) is non-volatile storage that retains data without power and holds the OS and user data.
Question 3: A technician replaces a cracked display on a smartphone, but touch response is erratic afterward. What is the most likely cause?
- Corrupted firmware
- Digitizer connector not fully seated (Correct answer)
- Failed GPS module
- Overheating CPU
Correct answer: Digitizer connector not fully seated
An improperly seated digitizer connector causes erratic or unresponsive touch input after a screen replacement.
Question 4: What does the term 'SoC' refer to in mobile device hardware?
- A secure onboard chip for NFC payments
- An integrated circuit combining CPU, GPU, modem, and memory controller (Correct answer)
- A software-on-chip virtualization layer
- A system-of-cables wiring harness
Correct answer: An integrated circuit combining CPU, GPU, modem, and memory controller
SoC (System on a Chip) integrates CPU, GPU, modem, and other subsystems onto a single die for efficiency and performance.
Question 5: A mobile device fails to detect a newly inserted SIM card. After confirming the SIM is valid, what should the technician check?
- Wi-Fi antenna placement
- SIM card tray and SIM reader contacts (Correct answer)
- Front-facing camera ribbon
- Speaker grille mesh
Correct answer: SIM card tray and SIM reader contacts
Bent or dirty SIM reader contacts prevent the device from detecting a valid SIM card.
Question 6: Which component is responsible for measuring a device's orientation and rotation for screen auto-rotate?
- Barometer
- Gyroscope (Correct answer)
- Proximity sensor
- Ambient light sensor
Correct answer: Gyroscope
The gyroscope measures angular rotation and enables features like screen auto-rotate and gaming motion controls.
Question 7: A technician is repairing a water-damaged phone. Which action should be performed FIRST after disassembly?
- Apply heat to dry the board
- Power on to test which components work
- Rinse with isopropyl alcohol (90%+) and inspect for corrosion (Correct answer)
- Replace the battery immediately
Correct answer: Rinse with isopropyl alcohol (90%+) and inspect for corrosion
Rinsing with high-purity isopropyl alcohol removes mineral deposits from water and stops ongoing corrosion before further damage occurs.
CMT Device Hardware & Software 2
A customer's smartphone charges very slowly even with the original charger.
After ruling out the cable, what component should a technician inspect next?