🔍 Key Concepts
• Focus on the electrical circuit components actually shown in the schematic (buzzer, relay, switches, fuses, plugs), not on the external fixtures like lantern glass.
• Think about which components have moving contacts that can arc, pit, or oxidize during normal operation and therefore need periodic servicing.
• Consider normal maintenance philosophy: fuses and insulation tests are usually condition-based, not replaced or tested on a rigid calendar without cause.
💭 Think About
• Look at the lower schematic: which device in the alarm/trouble portion of the circuit clearly operates mechanically and uses electrical contacts that open and close?
• For each answer choice, ask: does this task match a realistic, periodic maintenance need for the type of component named, or would it be done only when there is a problem?
• Which option specifically relates to a component that would be part of the alarm/trouble section of the circuit, as shown near the buzzer bus and trouble relay?
✅ Before You Answer
• Verify which items in the choices are truly circuit components on the panel diagram versus external fittings on the ship.
• Identify any device in the drawing that would have contact points subject to arcing when it is energized and de‑energized (look near the "TR0UBLE BUZZER" and "TROUBLE RELAY" labels).
• Eliminate any options that describe maintenance that would be unnecessarily frequent or not standard practice for fuses, insulation resistance tests, or fixture glass.