Charger emits a loud buzzing or humming noise during operation.

Safety first: Noise often comes from energized components. Turn off power before tightening or touching internal parts.

• Identify source: Carefully listen to locate whether the noise comes from the main power contactor area or the power supply/transformer area.
• Check mounting screws: With power OFF, tighten mounting screws for the contactor and any transformers or inductors.
• Inspect for loose laminations: If a transformer core is loose, it may buzz. In many cases, the entire power supply module must be replaced.
• Verify supply voltage: Low supply voltage can increase hum. Have an electrician confirm voltage is within spec.
• If noise is excessive or worsening: Replace the noisy component (typically the main power contactor or power supply module) to prevent eventual failure.