Home / AC SERVO DRIVE / Mitsubishi / MDS A and MDS B Series

Our Team Expertly Repairs Mitsubishi MDS-A and MDS-B Series AC Servo Drives

Here at Precision Zone, one of our specialties is the repair services of Mitsubishi AC Servo drives. One series that we often work on is the MDS-A/MDS-B single and double axis AC Servo series.

MDS-A and MDS-B drives are compact and lightweight AC servo drives. The dimensions have been standardized to allow easy installation in cabinets as well as creating an integrated appearance with the NC. The display screen allows for easy to read alarm codes (when applicable) as well as a quick way to check that each unit in the line is properly functioning.

These units offer a high speed CPU as well as a 100,000 pulse/rotation sup bicorn detector to allow faster and more precise interpolation. Positioning time and tracking has been improved through the incorporation of the stable position loop control (SHG control) method. The high speed CPU allows improved cutting performance and cutting precision during position control.

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

  • Visual Overview Check
  • Static Check
  • Static Test
  • Checks Under Power
  • 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 meg ohm metere, as well as any other necessary tools to assure quality repair work. Most importantly, every repair is fully tested in our custom-built simulators under load with a motor to replicate a real-life working environment.

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

Repair Process for MDS-A/MDS-B

Visual Overview Check

When conducting a visual check, the technician inspects the drive for any mechanical damage to the drive itself and any printed circuit boards. 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, printed circuit boards 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

Input Module Testing

On MDS-A/MDS-B units, input modules are tested by opening the drive and checking them within the drive housing. This is not easily accessible like the output module testing, so it’s not recommended to check input modules while onsite.

Output Module testing

Precision Zone repair technicians use digital multimeters with diode testing capabilities and also take resistance measurements to conduct a static test. For these units in particular, our team of technicians uses the diode function of the multimeter as well as huntron devices to check the output modules.

Positive Lead Negative Lead Reading
U Positive bus terminal 0.34-0.37V
V Positive bus terminal 0.34-0.37V
W Positive bus terminal 0.34-0.37V
Negative bus terminal U 0.34-0.37V
Negative bus terminal V 0.34-0.37V
Negative bus terminal W 0.34-0.37V

MDS-A/MDS-B Common Alarms

Alarm Code Description Checks
A.12
Memory Error		 The memory IC (SRAM or FROM) check sum was illegal
  • Attempt a few power cycles, if alarm continues to occur, contact Precision Zone for repair.
  • If intermittent, check issues with ambient temo, noise, grounding, etc
A.16
Pole Position Detection error		 The differential input of the U, V or W phase of the pole position detection signal of the OHE type detector were both “H” or “L”
  • Verify SV25
  • Tug feedback connector slightly to verify it's not loose
  • Check feedback cable with tester
  • Swap amp units to see if alarm follows amp or stays on axis
A.18
Initial Communication Error		 Initial communication error, absolute position or pole position from OHA (Absolute analog) type detector not correct
  • Refer to checks for A.16 above
A.21
No Signal Detected 2		 No signal detected (2), differential input of A, B or Z phase signal from machine end installed detector are both “H” or “L”
  • ‘4’, ‘5’, ‘8’, or ‘9’ is set in SV25, correctly change this value
  • Refer to A.20 in link provided below
A.32 (3A)
Very Common		 Power module error (Over current), IPM used in amp detected an over current
  • Disconnect motor leads from amp
  • Meg the Motor
  • Check resistance phase to phase to motor (U, V, W)
  • Check amp output legs to ground for any shorts
A.3B
Power Module Overheat		 Overheating of the IMP used in the servo drive was detected
  • Verify any cooling devices are functioning properly
  • Check operating ambient temperature
  • Check grounding and any noise generating devices
A.51
Overload Detection 2		 A current command exceeding 95% of the amplifier’s maximum current continued for one second or more
  • Disconnect motor leads from amp
  • Meg the motor
  • Check resistance phase to phase to motor (U, V, W)
  • Check amp output legs to ground for any shorts
A.59 Collision Detect 2
  • Verify rotary dial settings
A.9E Highspeed serial mutil-rotation counter error
  • Refer to A.25 in link provide below, starting at item 3
No Display Unit display stays blank when power is applied
  • Verify incoming control power, if absent when connected, disconnect and measure incoming leads again

For a full list of troubleshooting, the link below provides a list of checks for certain alarms on the Mitsubishi MDS-A/MDS-B Series AC Servo Drives and is a great troubleshooting reference.

https://s3.amazonaws.com/Icarus/DOCUMENTS/Mitsubishi_Alarms_Faults_3619.pdf

Need further troubleshooting assistance for the Mistubishi MDS-A/MDS-B AC Servo Drive series?

Take advantage of Precision Zone's Free Technical Support by calling 800-551-4420 or by emailing repair@precisionzone.com.

Find out why Precision Zone is the go-to when it comes to industrial repairs:

  • Quick and Flexible Service
  • Complete Simulation and Product Testing
  • Fully Refurbished, Not Just Repaired
  • Decades of Industry Experience
  • Superior Technology Knowledge and Support

Recently Repaired Products

Mitsubishi MDS-B-V2-3535 image MDS-B-V2-3535 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, Physical Damage to the Drive
Drive Series: MDS-B AC Servo
Number of Axes: 2-axis
Rated Capacity of Each Axis: 3.5/3.5kW

Mitsubishi MDS-B-V1-10 image MDS-B-V1-10 is an
Drives-AC Servo manufactured by Mitsubishi
Discovered issues: Bad Capacitor(s), Bad Circuit Board Component(s), Bad Cooling Fans, Bad Power Section/Board, Excessive Dirt/Debris, Leaky Capacitors (Open, Corroded Traces), Physical Damage to the Drive, No Display
Drive Series: MDS-B AC Servo
Number of Axes: 1-axis
Rated Capacity & Dynamic Braking Specification: 1.0kW; Built-in

Mitsubishi MDS-B-V1-45 image MDS-B-V1-45 is an
Drives-AC Servo manufactured by Mitsubishi
Discovered issues: Physical Damage to the Drive, Bad Capacitor(s), Bad Circuit Board Component(s), Bad Cooling Fans, Bad Gate Section/Board, Bad Magnetic Contactor, Relay, Bad Power Section/Board, Leaky Capacitors (Open, Corroded Traces), No Display
Drive Series: MDS-B AC Servo
Number of Axes: 1-axis
Rated Capacity & Dynamic Braking Specification: 4.5kW; Built-in

Mitsubishi MDS-B-V1-20 image MDS-B-V1-20 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, Bad Magnetic Contactor, Relay, Excessive Dirt/Debris, Leaky Capacitors (Open, Corroded Traces), Physical Damage to the Drive
Drive Series: MDS-B AC Servo
Number of Axes: 1-axis
Rated Capacity & Dynamic Braking Specification: 2.0kW; Built-in

Mitsubishi MDS-B-V2-3510 image MDS-B-V2-3510 is an
Drives-AC Servo manufactured by Mitsubishi
Discovered issues: Physical Damage to the Circuit Board/s, Physical Damage to the Drive
Drive Series: MDS-B AC Servo
Number of Axes: 2-axis
Rated Capacity of Each Axis: 3.5/1.0kW

Mitsubishi MDS-A-V2-3510 image MDS-A-V2-3510 is an
Drives-AC Servo manufactured by Mitsubishi
Discovered issues: Bad Control Section/Board, Bad Cooling Fans, Bad Gate Section/Board, Bad Magnetic Contactor, Relay, Bad Power Section/Board, Excessive Dirt/Debris, Leaky Capacitors (Open, Corroded Traces), Physical Damage to the Drive
Drive Series: MDS-A AC Servo
Number of Axes: 2-axis
Rated Capacity of Each Axis: 3.5/1.0kW

Mitsubishi MDS-B-V2-4535 image MDS-B-V2-4535 is an
Drives-AC Servo manufactured by Mitsubishi
Discovered issues: Bad Circuit Board Component(s), Bad Cooling Fans, Bad Magnetic Contactor, Relay, Excessive Dirt/Debris, Leaky Capacitors (Open, Corroded Traces)
Drive Series: MDS-B AC Servo
Number of Axes: 2-axis
Rated Capacity of Each Axis: 4.5/3.5kW

Mitsubishi MDS-B-V2-1010 image MDS-B-V2-1010 is an
Drives-AC Servo manufactured by Mitsubishi
Discovered issues: Bad Cooling Fans, Bad Magnetic Contactor, Relay, Bad Power Section/Board, Excessive Dirt/Debris, Leaky Capacitors (Open, Corroded Traces), No Display
Drive Series: MDS-B AC Servo
Number of Axes: 2-axis
Rated Capacity of Each Axis: 1.0/1.0kW

Mitsubishi MDS-A-V1-45 image MDS-A-V1-45 is an
Drives-AC Servo manufactured by Mitsubishi
Discovered issues: Bad Circuit Board Component(s), Blown Input Power Components, Excessive Dirt/Debris, Leaky Capacitors (Open, Corroded Traces), May Require Board Replacement
Drive Series: MDS-A AC Servo
Number of Axes: 1-axis
Rated Capacity & Dynamic Braking Specification: 4.5kW; Built-in

Mitsubishi MDS-B-V2-4520 image MDS-B-V2-4520 is an
Drives-AC Servo manufactured by Mitsubishi
Discovered issues: Bad Cooling Fans, Bad Capacitor(s), Bad Magnetic Contactor, Relay, Excessive Dirt/Debris, Leaky Capacitors (Open, Corroded Traces), Missing parts/components, Multiple signs of previous repair, Physical Damage to the Drive
Drive Series: MDS-B AC Servo
Number of Axes: 2-axis
Rated Capacity of Each Axis: 4.5/2.0kW

Mitsubishi MDS-B-V2-0505 image MDS-B-V2-0505 is an
Drives-AC Servo manufactured by Mitsubishi
Discovered issues: Bad Cooling Fans, Bad Gate Section/Board, Bad Magnetic Contactor, Relay, Bad Power Section/Board, Excessive Dirt/Debris, Leaky Capacitors (Open, Corroded Traces), No Display
Drive Series: MDS-B AC Servo
Number of Axes: 2-axis
Rated Capacity of Each Axis: 0.5/0.5kW

Mitsubishi MDS-B-V2-3520 image MDS-B-V2-3520 is an
Drives-AC Servo manufactured by Mitsubishi
Discovered issues: Bad Output Transistors/SCRs
Drive Series: MDS-B AC Servo
Number of Axes: 2-axis
Rated Capacity of Each Axis: 3.5/2.0kW

Mitsubishi MDS-B-V2-0503 image MDS-B-V2-0503 is an
Drives-AC Servo manufactured by Mitsubishi
Discovered issues: Bad Circuit Board Component(s), Bad Cooling Fans, Bad Power Section/Board, Excessive Dirt/Debris, Leaky Capacitors (Open, Corroded Traces)
Drive Series: MDS-B AC Servo
Number of Axes: 2-axis
Rated Capacity of Each Axis: 0.5/0.3kW

Mitsubishi MDS-B-V1-70 image MDS-B-V1-70 is an
Drives-AC Servo manufactured by Mitsubishi
Discovered issues: Bad Cooling Fans, Bad Gate Section/Board, Bad Magnetic Contactor, Relay, Bad Power Section/Board, Excessive Dirt/Debris, Leaky Capacitors (Open, Corroded Traces), No Display
Drive Series: MDS-B AC Servo
Number of Axes: 1-axis
Rated Capacity & Dynamic Braking Specification: 7.0kW; Built-in

Mitsubishi MDS-A-V2-0505 image MDS-A-V2-0505 is an
Drives-AC Servo manufactured by Mitsubishi
Discovered issues: Bad Output Transistors/SCRs
Drive Series: MDS-A AC Servo
Number of Axes: 2-axis
Rated Capacity of Each Axis: 0.5/0.5kW

Mitsubishi MDS-A-V2-3535 image MDS-A-V2-3535 is an
Drives-AC Servo manufactured by Mitsubishi
Discovered issues: Bad Cooling Fans, Bad Gate Section/Board, Bad Magnetic Contactor, Relay, Bad Power Section/Board, Excessive Dirt/Debris, Leaky Capacitors (Open, Corroded Traces)
Drive Series: MDS-A AC Servo
Number of Axes: 2-axis
Rated Capacity of Each Axis: 3.5/3.5kW

Mitsubishi MDS-A-V1-35 image MDS-A-V1-35 is an
Drives-AC Servo manufactured by Mitsubishi
Discovered issues: Bad Cooling Fans, Bad Gate Section/Board, Bad Magnetic Contactor, Relay, Bad Power Section/Board, Excessive Dirt/Debris, Leaky Capacitors (Open, Corroded Traces), No Display
Drive Series: MDS-A AC Servo
Number of Axes: 1-axis
Rated Capacity & Dynamic Braking Specification: 3.5kW; Built-in

Mitsubishi MDS-B-V2-2020 image MDS-B-V2-2020 is an
Drives-AC Servo manufactured by Mitsubishi
Discovered issues: Bad Circuit Board Component(s), Bad Cooling Fans, Bad Fuse, Bad Gate Section/Board, Bad Magnetic Contactor, Relay, Bad Power Section/Board, Excessive Dirt/Debris, Leaky Capacitors (Open, Corroded Traces)
Drive Series: MDS-B AC Servo
Number of Axes: 2-axis
Rated Capacity of Each Axis: 2.0/2.0kW

Mitsubishi MDS-A-V2-1010 image MDS-A-V2-1010 is an
Drives-AC Servo manufactured by Mitsubishi
Discovered issues: Bad Gate Section/Board, Bad Magnetic Contactor, Relay, Bad Power Section/Board, Excessive Dirt/Debris, Leaky Capacitors (Open, Corroded Traces)
Drive Series: MDS-A AC Servo
Number of Axes: 2-axis
Rated Capacity of Each Axis: 1.0/1.0kW

Mitsubishi MDS-A-V1-10 image MDS-A-V1-10 is an
Drives-AC Servo manufactured by Mitsubishi
Discovered issues: Bad Magnetic Contactor, Relay, Bad Power Section/Board, Excessive Dirt/Debris, Leaky Capacitors (Open, Corroded Traces), No Display
Drive Series: MDS-A AC Servo
Number of Axes: 1-axis
Rated Capacity & Dynamic Braking Specification: 1.0kW; Built-in

Mitsubishi MDS-B-V1-35 image MDS-B-V1-35 is an
Drives-AC Servo manufactured by Mitsubishi
Discovered issues: Bad Cooling Fans, Bad Magnetic Contactor, Relay, Bad Power Section/Board, Excessive Dirt/Debris, Leaky Capacitors (Open, Corroded Traces)
Drive Series: MDS-B AC Servo
Number of Axes: 1-axis
Rated Capacity & Dynamic Braking Specification: 3.5kW; Built-in

Mitsubishi MDS-A-V1-20 image MDS-A-V1-20 is an
Drives-AC Servo manufactured by Mitsubishi
Discovered issues: Bad Cooling Fans, Bad Fuse, Bad Magnetic Contactor, Relay, Bad Power Section/Board, Excessive Dirt/Debris, Leaky Capacitors (Open, Corroded Traces)
Drive Series: MDS-A AC Servo
Number of Axes: 1-axis
Rated Capacity & Dynamic Braking Specification: 2.0kW; Built-in

Mitsubishi MDS-B-V2-2010 image MDS-B-V2-2010 is an
Drives-AC Servo manufactured by Mitsubishi
Discovered issues: Bad Circuit Board Component(s), Bad Cooling Fans, Bad Magnetic Contactor, Relay, Excessive Dirt/Debris, Leaky Capacitors (Open, Corroded Traces)
Drive Series: MDS-B AC Servo
Number of Axes: 2-axis
Rated Capacity of Each Axis: 2.0/1.0kW

Mitsubishi MDS-B-V1-03 image MDS-B-V1-03 is an
Drives-AC Servo manufactured by Mitsubishi
Discovered issues: Physical Damage to the Drive, Bad Circuit Board Component(s), Bad Cooling Fans, Bad Power Section/Board, Excessive Dirt/Debris, Leaky Capacitors (Open, Corroded Traces)
Drive Series: MDS-B AC Servo
Number of Axes: 1-axis
Rated Capacity & Dynamic Braking Specification: 0.3kW; Built-in