The Super Vexta UDK5107NA is a 5‑phase stepper/servo driver that accepts 115 VAC and delivers up to 0.75 A per phase; it’s commonly paired with VEXTA UPD series motors in industrial motion control loops. Known failure modes for this unit include insulation breakdown or winding damage from overcurrent, burnt MOSFETs or ICs on the drive board, and loss of phase‑to‑phase connections that trigger “phase error” fault codes. First‑check diagnostics should begin with a visual inspection of the PCB for scorch marks or swollen capacitors, verify the input voltage is within spec and the output current limit is set correctly, then review any stored error logs or diagnostic LEDs for phase‑specific faults.[oss-gpt-20b]