converter adc may already be available in the machine control section and so forth even the current measuring or voltage measuring resistor may already be available by using a spare resistor or trace already present in circuitry of the machine in operation the control system then sends 102 power to the audio speaker to detect current voltage or power with the detector the detector circuit then sends 103 signals indicative of speaker consumption of current voltage or power to signal processing circuitry the signal processing circuitry converts the analog signals of a speaker to digital signals useful for comparison and a computer program then compares 104 the detected signals to the signal waveforms previously detected in operation of speakers that are known to be operating properly a look up table of such expected signals and their characteristics or parameters may be stored in memory of the microcontroller or in a memory accessible to the microcontroller using guidelines and logic from the program the microcontroller and the computer program then determine 105 whether the waveform is indicative or characteristic of an operational speaker or whether the speaker appears inoperable if the waveform conforms to the expected model the sampling of data may be repeated periodically as in a u201c test cycle u201d or start up procedure alternatively if the waveform conforms to expectations no action need be taken if the waveform appears to be consistent with damage or non operation of the.