The present invention provides a test device and a method enabling automatic detection of an imbalance in a power level of a channel. The test device includes a tuner, a power-level measurement system, and an evaluation unit. According to the method, a test channel is selected from a plurality of channels, by means of the tuner. A power level of the test channel and a total power level of the plurality of channels are measured, by means of the power-level measurement system. A ratio of the total power level of the plurality of channels to the power level of the test channel is then evaluated, by means of the evaluation unit, to detect an imbalance in a power level of the test channel.