What indication would a DEC system fault cause on the control box?

In a Yamaha system equipped with a DEC (Digital Electronic Control) unit, a fault in the system typically triggers a specific signal to alert the operator of an issue. The indication of a blue and orange light serves as a warning of a DEC system fault. This color combination has been designated to help technicians quickly identify that there is a malfunction requiring attention.

The blue light is often associated with operational modes or alerts, while the orange signifies a caution or an error state, signaling that the system is not functioning correctly. This clear visual indication allows for immediate troubleshooting and rectification, ensuring that technicians can take the necessary steps to resolve issues without delay.

Other options do not correctly represent the indication associated with a DEC system fault. A red light might suggest a critical failure, but it is a different category of alert compared to the blue and orange combination that directly refers to DEC faults. A flashing green light usually indicates normal operation or status checks, while having no indication would suggest the system is functioning perfectly or there is a complete failure in signaling, which is not the case during a DEC fault.