Power Amplifier · NAD · 218 THX

Diagnosis: Protection Relay Won't Click

The receiver is staying in protection mode or its speaker relay is not engaging.

Safe first checks

  1. Disconnect all speakers and speaker wires, then power the unit on again.
  2. Wait at least 10 seconds; some receivers delay the relay at startup.
  3. If the relay engages with speakers disconnected, inspect the speaker wiring for a short.
  4. If it never engages, do not connect speakers until a technician checks the amplifier for DC offset or a power-supply fault.

Next step

The next diagnostic stage should record whether the relay clicks with no speakers attached and whether any protection indicator is lit.