🔍 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.