Elevator Mechanic Practice Exam

What precautions must be taken when replacing a PCB in a controller?

1. Use a grounding wrist strap, and never remove anything with the power on

2. Wear rubber gloves and boots

3. Ensure room temperature is below 20°C

4. Use a wooden stick to ground

The correct answer is: Use a grounding wrist strap, and never remove anything with the power on

When replacing a PCB in a controller, it is important to take precautions to avoid damaging the sensitive electrical components. Option A is correct because using a grounding wrist strap is essential in preventing static electricity from damaging the PCB. Removing anything with the power still on can result in a short circuit or electrostatic discharge which can permanently damage the PCB. Option B is incorrect because wearing rubber gloves and boots will not prevent static electricity and can even create more static electricity. Option C is incorrect because the room temperature does not have a significant impact on the replacement process. Option D is incorrect because using a wooden stick does not provide proper grounding and can also damage the PCB.