Weko 9E324003MF7 Web Break Detector is a photoelectric sensor module used in industrial printing and coating lines to detect web presence or breakage. Common failure modes for this class of devices include optical lens contamination, photodiode degradation, power supply ripple, and signal line shorts or opens. Begin diagnostics by verifying the 12 V DC input voltage with a multimeter, inspecting the sensor housing for dust or debris on the optical window, checking the output signal to the controller for continuity and proper logic level, and reviewing any error codes displayed on the host system. If power and visual inspection are normal, test the photodiode circuit with an oscilloscope for expected waveform shape and amplitude.[oss-gpt-20b]