The Okuma BDU‑50A is a 3‑phase, brushless AC servo drive rated at 200/220 V and up to 50 A, commonly used in CNC machining centers for precise motor control. Typical failure modes include overheating of the power MOSFETs or IGBT modules, degradation of the internal capacitor bank, insulation breakdown between phase windings, and loss of communication with the host controller due to corrupted firmware or bad serial links. For this class of drives, common repair points are the cooling fan/heat sink, power supply filtering stages, and the drive’s internal DC bus voltage regulator.

First‑check diagnostic steps: verify that the input line voltage is within spec and that the 3‑phase balance is correct; inspect all connectors for corrosion or loose contacts and confirm the drive’s status LEDs or fault codes via the user interface; finally, check the temperature of the MOSFETs/IGBTs under load and examine the DC bus voltage ripple with an oscilloscope.[oss-gpt-20b]