Nissei N9CPU‑02 is the central processing unit board for Nissei injection molding machines, typically mounted in the NC9000 control system and interfacing with motor drives, hydraulic controls, and operator panels. Common failure modes on this class of industrial CPU boards include power supply degradation (brown‑out or over‑voltage spikes), capacitor leakage or bulging, solder joint fatigue at high‑temperature points, and firmware corruption due to improper updates. Initial troubleshooting should verify the 24 V DC input rail with a calibrated multimeter, inspect for visual signs of component damage such as cracked capacitors or burn marks, and check the serial diagnostic port for error codes that indicate CPU lock‑up or communication loss.[oss-gpt-20b]