What indicator lights up on the RSC when the azimuth drive circuit breaker is open?

The indicator that lights up on the Radar System Controller (RSC) when the azimuth drive circuit breaker is open is the one that directly reflects an issue with the circuit breaker status. In this case, "ANT CB OPEN" provides a clear and specific indication that the antenna circuit breaker is not engaged, signaling to the operator that there is a problem within the azimuth drive circuitry. This is crucial for ensuring the radar system's operational integrity, as the azimuth drive is vital for the antenna's movement, which in turn is necessary for tracking and target acquisition in air defense.

Other indicators listed relate to different conditions. For instance, "ANT FAULT" would indicate a fault with the antenna itself, "XMTR WARMING" pertains to the transmitter's operational state, and "POWER FAULT" indicates issues with the overall power supply to the system. Each of these serves a different purpose and would illuminate under different circumstances, further emphasizing the importance of knowing what each indicator represents in the context of radar operation and troubleshooting.