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Precision Zone Expert Repair Services for Mitsubishi MR-J2 Series AC Servo Drive

Here at Precision Zone, one of our specialties is the repair services of Mitsubishi AC Servo Drives. One series that we often work on it the MR-J2 AC Servo series.

MR-J2 servo drives are offered in sizes ranging from 100W up to 3500W and have options for single or three-phase AC200-230V as well as an option for single-phase AC100V input power. It is possible to control these units using position mode, speed mode, and even torque mode.

This series offers a spot for the absolute position data backup battery which is easily accessible right near the seven-segment LED displays. These displays allow for quick and easy reading of the servo’s status as well as alarm numbers, making troubleshooting much more clear with the alarms being readily and easily available to see. Directly under these displays, this series of servo drive offers operation buttons to easily change display modes, diagnose issues, and enter/change stored parameters. These units also have optional regenerative terminals. Factory default, terminals P to D is jumped together. If a regen option is used, that jumper must be removed and the regen option is connected to terminals P and C.

When assessing the functionality of a drive, our repair team conducts a four-step check:

  • 1. Visual Overview
  • 2. Static Test
  • 3. Checks Under Power
  • 4. Alarm Codes Verification

This overview is Precision Zone’s basic troubleshooting process. Once our repair team starts on the job, we use specialized and customized testing fixtures, Huntron trackers, signal generators, oscilloscopes, milli and mega ohm meters, as well as any other necessary tools we need to assure quality repair work. Most importantly, every repair is fully tested in our custom-built simulators under load with a motor to replicate real-life working environment.

Precision Zone goes as far as using heating chambers and overnight dynamic testing, when applicable, to guarantee performance of the repaired product when it arrives back with the customer.

Repair Process for Mitsubishi MR-J2 AC Servo Drives

Visual Overview

When conducting a visual check, the technician inspects the drive for any mechanical damage to the drive itself and any printed circuit boards (PCB). The technician then proceeds to verify connections are tight and correct inside the drive and there are no loose screws, wires or debris. Additionally, the unit is checked for any burn marks on the components, PCBs or chassis. During the visual inspection, excessive dirt on cooling components is noted as well as the functionality of the heat sink.

Basic Static Check

MR-J2-100 or Less


Input Module Testing

On MR-J2 units with a 1000W rating or less, the input modules are tested by use of a digital multimeter with diode checking capabilities. The positive and negative bus pins can be accessed through the green control plug. While facing the drive (input/output terminals on the top) the positive pin is the third (3) from the top and the negative pin is the last (6, bottom) pin on the plug.

Positive Lead Negative Lead Reading
L1 Positive bus pin (3) 0.54V - 0.56V
L2 Positive bus pin (3) 0.54V - 0.56V
L3 Positive bus pin (3) 0.54V - 0.56V
Negative bus pin (3) L1 0.54V - 0.56V
Negative bus pin (3) L2 0.54V - 0.56V
Negative bus pin (3) L3 0.54V - 0.56V


Output Module Testing

Using the same type of test as above, the output modules can be checked as well. Our technicians are also equipped with huntron devices further verify their integrity.

Positive Lead Negative Lead Reading
U Positive bus pin (3) 0.38V - 0.41V
V Positive bus pin (3) 0.38V - 0.41V
W Positive bus pin (3) 0.38V - 0.41V
Negative bus pin (3) U 0.38V - 0.41V
Negative bus pin (3) V 0.38V - 0.41V
Negative bus pin (3) W 0.38V - 0.41V


MR-J2-200 or Larger


Input Module Testing

On MR-J2 units with a 2000W rating or larger, the input modules are tested by use of a digital multimeter with diode checking capabilities. The positive and negative bus pins can be accessed through upper terminal strip. Terminal ‘P’ will represent the positive bus terminal and ‘N’ will represent the negative bus terminal.

Positive Lead Negative Lead Reading
L1 Positive bus terminal 0.54V - 0.56V
L2 Positive bus terminal 0.54V - 0.56V
L3 Positive bus terminal 0.54V - 0.56V
Negative bus terminal L1 0.54V - 0.56V
Negative bus terminal L2 0.54V - 0.56V
Negative bus terminal L3 0.54V - 0.56V


Output Module Testing

Using the same type of test as above, the output modules can be checked as well.

Positive Lead Negative Lead Reading
U Positive bus terminal 0.38V - 0.41V
V Positive bus terminal 0.38V - 0.41V
W Positive bus terminal 0.38V - 0.41V
Negative bus terminal U 0.38V - 0.41V
Negative bus terminal V 0.38V - 0.41V
Negative bus terminal W 0.38V - 0.41V


List of Mitsubishi MR-J2 Common Alarms

Alarm Code Description Checks
A.10
Undervoltage		 Power Supply Voltage Dropped to:
MR-J2-_x: 160v or less
MR-J2-_x1: 83v or less
  • Verify incoming power voltage
  • Power switched on within 5 seconds after switching off
  • CN1A, CN1B, or CN3 or disconnected; check cables
A.24
Motor Output Ground Fault		 Ground fault occurred ar servo motor outputs (U, V, W)
  • Verify cables are properly connected
  • Check cables for poor insulation
  • Faulty circuitry within in servo (check for alarm with U, V, W disconnected)
A.25
Absolute Position Error		 Absolute position data error; power was applied for the first time in an absolute position detection system
  • Verify absolute position battery is within specs
  • Perform encoder realignment
  • Perform homing procedure
A.32
Overcurrent		 Current flow has exceeded the acceptable maximum amount of current through the servo
  • Check cables for poor insulation
  • Perform megaohm test on motor
  • Use "Output Module Testing" test to verify modules
  • Check for ground faults
A.51
Overload		 Machine collision, or similar situation, caused max output to flow through servo
  • Check for any collisions
  • Verify proper cable connections
  • Attempt to auto-tune
  • Check encoder, if possible


For a full list of Mistubishi MR-J2 alarm troubleshooting, extracted from the manual:

https://s3.amazonaws.com/Icarus/DOCUMENTS/Mitsubishi_Alarms_Faults_3638.pdf

This list of checks for certain alarms is primarily a good starting point and if any further troubleshooting or technical support is needed feel free to contact us via phone or email to get in touch with our experienced tech support team.

Precision Zone Repair Advantage for Mitsubishi MR-J2 Series AC Servo Drives

  • Free Quotes and Evaluations
  • Competitive Prices
  • 1 Year Warranty
  • Flexible Rush Repair Options Available

Contact Us To Start Your Repair Today!


Recently Repaired Products

Mitsubishi MR-J2-40A image MR-J2-40A is an
Drives-AC Servo manufactured by Mitsubishi
Discovered issues: Bad Capacitor(s), Bad Circuit Board Component(s), Bad Gate Section/Board, Bad Power Section/Board, Excessive Dirt/Debris, Leaky Capacitors (Open, Corroded Traces)
Drive Type: MR-J2 AC Servo Amplifier
Rated Output: 400 W
Interface: General Purpose Interface
Power Supply: Three-phase AC 200-230V
Modification: None

Mitsubishi MR-J2-60A image MR-J2-60A is an
Drives-AC Servo manufactured by Mitsubishi
Discovered issues: Bad Capacitor(s), Bad Circuit Board Component(s), Bad Gate Section/Board, Bad Magnetic Contactor, Relay, Bad Power Section/Board, Excessive Dirt/Debris, Leaky Capacitors (Open, Corroded Traces)
Drive Type: MR-J2 AC Servo Amplifier
Rated Output: 600 W
Interface: General Purpose Interface
Power Supply: Three-phase AC 200-230V
Modification: None

Mitsubishi MR-J2-200C image MR-J2-200C is an
Drives-AC Servo manufactured by Mitsubishi
Discovered issues: Bad Capacitor(s), Bad Circuit Board Component(s), Bad Cooling Fans, Bad Magnetic Contactor, Relay, Bad Power Section/Board, Excessive Dirt/Debris, Leaky Capacitors (Open, Corroded Traces)
Drive Type: MR-J2 AC Servo Amplifier
Rated Output: 2000 W
Interface: Positioning Function Built-in
Power Supply: Three-phase AC 200~230V;If 100W to 750W, Single-phase AC230V Also Supplied
Modification: None

Mitsubishi MR-J2-40B image MR-J2-40B is an
Drives-AC Servo manufactured by Mitsubishi
Discovered issues: Bad Battery, Bad Capacitor(s), Bad Circuit Board Component(s), Excessive Dirt/Debris, Missing parts/components, Physical Damage to the Drive
Drive Type: MR-J2 AC Servo Amplifier
Rated Output: 400 W
Interface: SSCNET Interface
Power Supply: Three-phase AC 200~230V;If 100W to 750W, Single-phase AC230V Also Supplied
Modification: None

Mitsubishi MR-J2-200B image MR-J2-200B is an
Drives-AC Servo manufactured by Mitsubishi
Discovered issues: Excessive Dirt/Debris, Leaky Capacitors (Open, Corroded Traces)
Drive Type: MR-J2 AC Servo Amplifier
Rated Output: 2000 W
Interface: SSCNET Interface
Power Supply: Three-phase AC 200~230V;If 100W to 750W, Single-phase AC230V Also Supplied
Modification: None

Mitsubishi MR-J2-100A-S01 image MR-J2-100A-S01 is an
Drives-AC Servo manufactured by Mitsubishi
Discovered issues: Bad Battery, Bad Capacitor(s), Bad Circuit Board Component(s), Non-supported product - Cannot Test, Missing parts/components
Drive Type: MR-J2 AC Servo Amplifier
Rated Output: 1000 W
Interface: General Purpose Interface
Power Supply: Three-phase AC 200-230V
Modification: S01

Mitsubishi MR-J2-200A image MR-J2-200A is an
Drives-AC Servo manufactured by Mitsubishi
Discovered issues: Excessive Dirt/Debris, Leaky Capacitors (Open, Corroded Traces), Missing parts/components, Physical Damage to the Drive
Drive Type: MR-J2 AC Servo Amplifier
Rated Output: 2000 W
Interface: General Purpose Interface
Power Supply: Three-phase AC 200-230V
Modification: None

Mitsubishi MR-J2-100A image MR-J2-100A is an
Drives-AC Servo manufactured by Mitsubishi
Discovered issues: Missing parts/components
Drive Type: MR-J2 AC Servo Amplifier
Rated Output: 1000 W
Interface: General Purpose Interface
Power Supply: Three-phase AC 200-230V
Modification: None

Mitsubishi MR-J2-40A1 image MR-J2-40A1 is an
Drives-AC Servo manufactured by Mitsubishi
Discovered issues: Excessive Dirt/Debris, Missing parts/components
Drive Type: MR-J2 AC Servo Amplifier
Rated Output: 400 W
Interface: General Purpose Interface
Power Supply: Single-phase AC100V
Modification: None

Mitsubishi MR-J2-10A1 image MR-J2-10A1 is an
Drives-AC Servo manufactured by Mitsubishi
Discovered issues: Physical Damage to the Drive, Bad Battery, Bad Capacitor(s), Bad Circuit Board Component(s), Bad Input Diodes/SCRs, Bad Magnetic Contactor, Relay, Missing parts/components, Multiple signs of previous repair
Drive Type: MR-J2 AC Servo Amplifier
Rated Output: 100 W
Interface: General Purpose Interface
Power Supply: Single-phase AC100V
Modification: None

Mitsubishi MR-J2-350A image MR-J2-350A is an
Drives-AC Servo manufactured by Mitsubishi
Discovered issues: Bad Capacitor(s), Bad Circuit Board Component(s), Bad Cooling Fans, Bad Gate Section/Board
Drive Type: MR-J2 AC Servo Amplifier
Rated Output: 3500 W
Interface: General Purpose Interface
Power Supply: Three-phase AC 200-230V
Modification: None

Mitsubishi MR-J2-20A image MR-J2-20A is an
Drives-AC Servo manufactured by Mitsubishi
Discovered issues: Missing parts/components, Passed Testing - Highly Recommend Recondition
Drive Type: MR-J2 AC Servo Amplifier
Rated Output: 200 W
Interface: General Purpose Interface
Power Supply: Three-phase AC 200-230V
Modification: None

Mitsubishi MR-J2-20A-A28 image MR-J2-20A-A28 is an
Drives-AC Servo manufactured by Mitsubishi
Discovered issues: Bad Circuit Board Component(s), Excessive Dirt/Debris, Leaky Capacitors (Open, Corroded Traces)
Drive Type: MR-J2 AC Servo Amplifier
Rated Output: 200 W
Interface: General Purpose Interface
Power Supply: Three-phase AC 200-230V
Modification: A28

Mitsubishi MR-J2-10B image MR-J2-10B is an
Drives-AC Servo manufactured by Mitsubishi
Discovered issues: Bad Circuit Board Component(s)
Drive Type: MR-J2 AC Servo Amplifier
Rated Output: 100 W
Interface: SSCNET Interface
Power Supply: Three-phase AC 200~230V;If 100W to 750W, Single-phase AC230V Also Supplied
Modification: None

Mitsubishi MR-J2-10A-A28 image MR-J2-10A-A28 is an
Drives-AC Servo manufactured by Mitsubishi
Discovered issues: Bad Circuit Board Component(s), Bad Output Transistors/SCRs, Bad Capacitor(s)
Drive Type: MR-J2 AC Servo Amplifier
Rated Output: 100 W
Interface: General Purpose Interface
Power Supply: Three-phase AC 200-230V
Modification: A28

Mitsubishi MR-J2-100A-A28 image MR-J2-100A-A28 is an
Drives-AC Servo manufactured by Mitsubishi
Discovered issues: Bad Capacitor(s), Bad Circuit Board Component(s), Bad Output Transistors/SCRs
Drive Type: MR-J2 AC Servo Amplifier
Rated Output: 1000 W
Interface: General Purpose Interface
Power Supply: Three-phase AC 200-230V
Modification: A28