What should be checked if set-top boxes transmit above 55 dBmV?

When set-top boxes (STBs) transmit signals above 55 dBmV, it is crucial to evaluate the value of the attenuator pad at the STB input. The primary reason for this is that excessive signal levels can lead to distortion and poor signal quality. An attenuator pad is used to reduce the input signal strength to an acceptable level, ensuring that the STB operates within its optimal operating range. Checking the value of this attenuator pad helps confirm whether it is appropriately set to manage high input signals, which is essential for maintaining the quality of both the broadcast and the viewing experience.

In cases where the transmitted power is excessively high, other checks, such as input signal strength, outdated firmware, or power supply voltage, might be relevant but would not directly address the immediate issue concerning signal transmission levels. Hence, verifying the attenuator pad is the most direct and pertinent action when signals exceed the recommended threshold.