If the off-air monitor speaker goes silent and the power output meter reads zero, what is the most likely issue?

The most likely issue in this scenario is that the transmitter has failed. When both the off-air monitor speaker goes silent and the power output meter indicates zero, it suggests that the transmitter is not functioning correctly. The transmitter's role is to take the audio and video signals and broadcast them; if it fails, no signal will be emitted, resulting in silence from the monitor and a reading of zero on the output meter.

While other options address potential issues in a broadcasting setup, they do not align as closely with the symptoms observed. For instance, if the power cable were disconnected, there would generally be no power to the entire system, which may not specifically lead to a zero output reading; check indicators would usually show other failures. Similarly, while loss of the audio feed could result in silence from the monitor, it may not necessarily affect the power output, which is specifically at zero. Moreover, needing servicing for the monitor itself wouldn’t impact the power output meter reading, as the issue appears to lie at the transmission level where output should be generated.

The failure of the transmitter directly accounts for both symptoms: the absence of audio from the monitor and the lack of output signal, reinforcing that the transmitter is the central issue at hand.