10.04.2025 by Viktor Siebert
When Supposedly Repaired Devices Return
Recently, we received two Mitsubishi MR-J2-60CT servo drive units from a customer for overhaul. At first, it appeared to be routine work, but after our initial inspection, it quickly became evident that the units had already been opened and tampered with.
Clarifying the Background – Competitor at Work
We contacted the customer to inquire if someone else had previously attempted repairs on the servo drives. Our suspicion was confirmed: a competitor had indeed already worked on the drives. Although they couldn’t detect any obvious faults, they replaced the capacitors and charged the customer significantly. Since then, the customer has been involved in a legal dispute with the previous service provider.
Our Detailed Diagnostics Provide Clarity
Initially, our examination also revealed no apparent issues. However, instead of hastily declaring the drives operational, we decided to dig deeper. Our technician requested the exact motor model from the customer and conducted an intensive load test using an identical motor, thanks to our extensive collection of test motors.
Sure enough, after approximately 30 minutes under full load, both drives indicated an overload fault.
Thorough Troubleshooting with Advanced Technology
Our technician conducted an in-depth fault analysis using an oscilloscope and thermal imaging camera. This clearly exposed issues previously hidden: several components, notably the output stage transistor and its control circuit, were defective. They operated normally without load but overheated significantly under load, causing intermittent failures.
Successful Repair Through In-depth Analysis
Thanks to our thorough and systematic testing procedures, we pinpointed the exact cause of the problem. The defective components were carefully replaced, and after reinstallation, both Mitsubishi MR-J2-60CT servo drives performed flawlessly again.
Conclusion – Only Comprehensive Diagnostics Ensure Lasting Solutions
This case vividly demonstrates the importance of thoroughly analyzing faults rather than performing superficial repairs. Especially with complex industrial devices like the Mitsubishi MR-J2-60CT servo drives, sophisticated testing methods are crucial to ensure reliable and lasting results.
Here are photos of the devices shortly before shipping:
The Mitsubishi MR-J2-60CT servo drive is part of the MR-J2 series by Mitsubishi Electric. It delivers 600 watts of power and is specifically designed for precise industrial servo motor control. The drive supports direct programming of positioning and motion sequences. An optional battery can be integrated to retain positional data even when powered off. Suitable for use with HC series motors.
Similar models: MR-J2-60C, MR-J2-60CP
For more details about our Yaskawa repair services, visit: Mitsubishi MR-J2S Servo Drive Repairs
📞 Feel free to contact us if you have any questions about your Mitsubishi drive technology!
