The Hitachi CU2681B is an industrial control board used in CNC machine and automation equipment, typically serving as the main logic and power interface for motor drives and I/O modules. Common failure points on this class of boards include burnt or swollen electrolytic capacitors, damaged gate‑driver ICs, shorted MOSFET channels, and cracked PCB traces from vibration or thermal cycling; power supply rails (±12 V, +5 V) are also frequent culprits. First‑check diagnostics should begin with a visual inspection for burn marks or component damage, verify all input and output voltage levels against the datasheet, and confirm that the board’s status LEDs or diagnostic ports indicate normal operation before proceeding to deeper fault isolation.[oss-gpt-20b]