The SanRex WK‑2973 is an industrial PC/PLC add‑on board used for machine‑control and welding applications. Common failure modes reported include loss of main power while high‑voltage outputs remain active, indicating possible supply or regulator faults; transformer short detection often passes but downstream protection devices may still be tripped. Typical points of failure are the onboard DC/DC converters, MOSFET driver stages, and I/O interface circuitry that can burn out under over‑current conditions. First‑check diagnostics: verify input voltage levels and polarity on the board’s power pins; inspect for burnt components or blown fuses on the high‑voltage regulator section; review any diagnostic LEDs or error codes displayed by the host PLC to isolate a specific fault block.[oss-gpt-20b]