The Edwards SCU‑1500 is a universal turbomolecular pump controller that incorporates Auto Vibration Reduction (AVR) and an auto‑balancing system to maintain low vibration levels during high‑vacuum operation. Common failures on this model include power supply degradation or incorrect voltage, firmware corruption leading to error codes, failure of the AVR sensor circuitry, and loss of communication with the pump motor drive. First‑check diagnostics should verify 200–240 V input is within spec, inspect all power connectors for loose or corroded contacts, review any displayed error codes against the instruction manual, and perform a visual inspection of the AVR sensor assembly and related wiring for signs of wear or damage.[oss-gpt-20b]