Practice Test Geeks(CMT) Certified Mobile Tech Practice Test
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Device Troubleshooting & Repair Flashcards

7 cards from real CMT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Device Troubleshooting & Repair flashcards as text

  1. A phone charges slowly on all cables and chargers. A cotton swab reveals compacted lint in the charging port. What is the correct cleaning technique?

    Answer: Carefully remove debris with a non-conductive plastic spudger or wooden toothpick

    A non-conductive tool allows safe debris removal without bending charging pins or causing short circuits.

  2. After a water damage repair, a device boots to the OS but has no cellular signal. All other functions work. What component is most suspect?

    Answer: Cellular baseband module or its antenna connections

    Water damage often corrodes the baseband processor or antenna connector pads, eliminating cellular function while leaving Wi-Fi and other features intact.

  3. A technician is replacing the display on an iPhone and must heat the adhesive. What is the maximum recommended temperature to avoid damaging the battery?

    Answer: 60°C (140°F)

    Heating adhesive above approximately 60°C risks thermal runaway in lithium batteries; 60°C is the safe upper limit for most repair heating.

  4. A customer reports their phone's GPS is inaccurate indoors but works perfectly outdoors. What is the most appropriate response?

    Answer: Explain that GPS requires clear line of sight to satellites and works as intended

    GPS signals are significantly attenuated by building materials, making indoor GPS inherently inaccurate—this is normal device behavior, not a defect.

  5. You are repairing a device and notice the motherboard has a cracked solder joint on the power management IC. This repair requires:

    Answer: BGA rework station with hot air and stencils

    BGA (Ball Grid Array) ICs require hot-air rework stations to properly reflow all solder balls simultaneously without damaging surrounding components.

  6. A phone vibrates once when a charger is plugged in but won't charge. Battery voltage measures 3.2V. What does this indicate?

    Answer: The battery is in a deep discharge state requiring trickle charge or replacement

    3.2V is below the typical 3.4V threshold for normal charging; the device recognizes the charger (vibrates) but the battery management system applies trickle charge or refuses full charge.

  7. Which tool is essential for measuring voltage and continuity when diagnosing a no-power condition on a logic board?

    Answer: Digital multimeter (DMM)

    A DMM measures DC voltage at power rails and tests continuity of traces, making it the primary tool for no-power diagnosis.