The Chadwick Helmuth Strobex 135M‑11 is a lightweight, handheld strobe lamp that operates directly from a 28 VDC ship or aircraft power source and uses a high‑intensity flash tube to illuminate retro‑reflective targets on rotor blades. Known failure modes for this model include flash‑tube burnout (often due to over‑voltage or aging), oscillator/locking‑mechanism malfunction leading to loss of “stacking” or “spreading” mode, and power‑regulation board failures that cause intermittent operation or complete shutdown. First‑check diagnostics should verify the 28 VDC supply voltage and continuity to the strobe housing, inspect the flash tube for visible damage or burn marks, and test the oscillator circuit with an oscilloscope or multimeter for proper frequency output.[oss-gpt-20b]