Question 14
If a mobile phone accidentally falls into a cup of salty water,
- List four steps that should be taken to prevent damage to the phone;
- State two components of the phone that may require attention if the phone does not power on after carrying out the steps listed in 14(a).
- (c) State two actions each that can be taken on the component listed in 14(b) to restore the phone to its functional state.
- Identify Figs. 6.
-
State the name and function of the parts labelled:
- X;
- Y;
- Z.
Observation
Most candidates attempted this question and the performance was good. This is due to increased awareness of the subject, engagement of qualified personnel to teach the subject and more exposure of candidates to practical work.
The expected answers are:
-
Steps required to prevent damage to phone recovered from salty water
- Remove the phone immediately from the water;
- Ensure it is switched off;
- Do not attempt to charge it immediately;
- Remove the battery, SIM card, memory card and other accessories;
- Attempt to dry the phone partially by dabbing;
- Ensure the phone is exposed to dry air for complete dryness before switching it on.
-
Components that may require attention if phone does not power on
- Power IC
- PCB
- Battery
- Battery connector
-
Actions to be taken on Power IC
- Test its status using the multimeter
- Replace if faulty
Actions to be taken on PCB- Physical inspection for corrosion
- Clean using thinner or PCB cleaner
- dry using rework station
Actions to be taken on Battery- Check the terminals for corrosion
- Clean terminals if corroded
- Check the voltage level using a multimeter
- If drained, charge battery
- If bad, replace battery
Actions to be taken on Battery connector- Check for corrosion
- If corroded, clean
- If damaged, replace
- Fig. 6: Digital Multimeter
-
Name and Function of labelled parts
X: Control knob
Used for selecting the parameters for measurement
Y: High current terminal
Used for testing high current in the range of 10Amperes
Z: Probes/Terminals
Used for testing parameters such as voltage, low current, resistance e.t.c.