Mitsubishi Electric MELSERVO MR-J4 Repair
The Mitsubishi Electric MELSERVO MR-J4 is a motion-control drive used to regulate servo motor speed, torque, and position in high-precision industrial machinery.
| Brand | Mitsubishi Electric |
| Equipment | MR-J4-40A-RJ |
| Equipment Category | MELSERVO MR-J4 |
| Industry | Chemical |
| Fault Reported |
|
| 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.
1. BEFORE
2. DISASSEMBLY
3. INSPECTION
4. FUNCTIONAL TESTING
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-circuit power voltage drop or supply interruption.
- AL.16 – Encoder error: Encoder cable/communication/encoder circuit problem.
- AL.20 – Encoder communication error: Feedback communication loss or encoder/cable fault.
- AL.24 – Main circuit error: Power-stage/main-circuit problem.
- AL.30 – Regenerative error: Regeneration/braking circuit or resistor issue.
- AL.32 – Overcurrent: Power stage overcurrent, short circuit or overload.
- AL.33 – Overvoltage: DC-bus overvoltage due to supply or regenerative energy.
- AL.45 – Main circuit device overheat: Power device temperature exceeded limit.
- AL.50 – Overload 1: Continuous overload / motor thermal load excessive.
- AL.51 – Overload 2: High short-duration overload / locked or overloaded axis.
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-J4 repair in Egypt for AL.10, AL.16, AL.20 and other common faults. Professional diagnosis, repair and testing by EISAC Autom...
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