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REPAIR CASE STUDY SR-1262

Mitsubishi Electric MELSERVO MR-J3 Repair

The Mitsubishi Electric MELSERVO MR-J3 is a motion-control drive used to regulate servo motor speed, torque, and position in high-precision industrial machinery.

Brand Mitsubishi Electric
Equipment MR-J3-10BS1
Equipment Category MELSERVO MR-J3
Industry Plastics
Fault Reported
  • Servo drive reports encoder, overcurrent, power-stage, or axis-control faults and the axis cannot run normally.
Repair Turnaround Time Typical reference: 3–6 working days

The Challenge

Loss of the servo axis stopped accurate machine movement and prevented normal production cycles.

Diagnosis

  • The DC bus, IGBT stage, driver board, current feedback, encoder interface, control power, communication circuitry, and cooling system were evaluated.

Our Solution

  • Failed electronic components were replaced where required, PCB defects and solder joints were restored, cooling was serviced, and the drive was tested with compatible feedback or motor simulation.

Testing Performed

  • Power-up test; DC-bus test; power-stage test; encoder/feedback test; communication test; axis enable test; thermal burn-in.

Final Result

The reference repair process restores normal functional operation after the unit passes the defined electrical, communication, motion, or load checks applicable to the equipment.

Common Fault Codes & Causes

  • AL.10 – Undervoltage: Control/main power voltage drop, supply interruption or input circuit issue.
  • AL.12 – Memory error 1 (RAM): Internal memory/control board fault.
  • AL.13 – Clock error: Internal clock/control electronics fault.
  • AL.15 – Memory error 2 (EEP-ROM): EEPROM/control board fault.
  • AL.16 – Encoder error 1: Encoder communication/cable/connector or encoder fault at power-up.
  • AL.17 – Board error: Internal board/control electronics fault.
  • AL.20 – Encoder error 2: Encoder communication or feedback fault during operation.
  • AL.21 – Encoder error 3: Encoder/feedback data error during operation.
  • AL.24 – Main circuit error: Power circuit, DC bus or power-stage fault.
  • AL.50 – Overload 1: Excessive continuous motor load, jam or thermal overload.

Preventive Maintenance

  • Inspect motor and feedback cables, maintain cabinet cooling, prevent overloads, check grounding, and investigate repeated fault codes before continued operation.

Related Services

  • Industrial Electronics Repair; Servo Motor Repair; Servo Drive Repair; PLC/HMI/VFD Repair; PCB Repair

Need Professional Repair?

Mitsubishi Electric MELSERVO MR-J3 repair in Egypt for AL.10, AL.12, AL.13 and other common faults. Professional diagnosis, repair and testing by EISAC Autom...

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