Precision Zone Okuma BLII-D AC Servo Drive Repair Experts

At Precision Zone, we specialize in Okuma product repairs which include a wide range of AC Servo Drives. One of the many types of servos we service is the Okuma BLII-D servo.

Okuma’s BLII-D servo amplifiers come in two flavors – a single axis or dual axis offering. The naming convention of the unit distinctly identifies the power rating of the axes. The single axis drives range from 15kW to 150kW whereas the dual axis version will range between 15kW and 75kW.

The drive is designed to be compact and efficient while allowing for easy to see alarm and status monitoring. Using check pins on the main servo control board, motor speed and torque can be check as voltage outputs.

When assessing the functionality of a Okuma BLII-D Servo Drives, our highly skilled repair team of engineers and technicians employs a basic four step troubleshooting process:

    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 Okuma BLII-D Servos

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. 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

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 0.34V-0.40V
V Positive Bus Terminal 0.34V-0.40V
W Positive Bus Terminal 0.34V-0.40V
Negative Bus Terminal U 0.34V-0.40V
Negative Bus Terminal V 0.34V-0.40V
Negative Bus Terminal W 0.34V-0.40V

Checks Under Power and Alarm Code Verification

Upon successfully passing all visual and static checks, the drive is tested under power. Any reported alarm codes are verified and if no alarms are present or once the drive has been fully repaired, the drive is tested in our Okuma series simulator. Alarms and drive status can be verified on the LEDs directly on the servo pack.

On the BLII-D servo packs, there are a handful of red LEDs to display alarm status. A green LED (PON) shows power is supplied to the control board and a yellow LED (OP) turns off once the machine ready signal is received. A few of the remaining red LEDs describe alarms as shown in the following table.

Common Alarms for the Okuma BLII-D Servo Series

Alarm Code Description Quick Checks
OCM Over-current in the motor
  • Check wiring and ensure that all terminal screws are tight
  • Check the motor and motor cables for low winding resistance (meg the motor)
OCS Over-current in the servo
  • Ensure that the inter-board connectors are securely inserted between the control and power boards.
  • Power off, disconnect motor and power up. If LED is still lit, repair of the servo drive is necessary
OV DC Voltage is abnormally high
  • Measure the incoming R-S-T voltages within a multimeter. Standard voltage levels reside between 170 and 222VAC
UV Under Voltage
  • Check incoming power with a multimeter
  • Check to make sure voltage input is at least 170VAC
  • Make sure circuit breaker is ON
ROH Regenerative discharge is overheating
  • Ensure that the inter-bond connectors are securely inserted between the control and power boards
  • Check the screws on THR and COM terminals
CIRCUIT BREAKER TRIPS
  • Check all wiring
  • Statically check the protection diodes on IGBT
  • Check diode module

Precision Zone offers free technical support on any component that you may be having issues with. We understand that when your machine goes down, your business stops. That is why our number one goal is to provide you with the best service possible so that you can get back up and running immediately. For more information on troubleshooting the Okuma BLII-D AC Servo Drives or for any other machine related issues, please contact us via phone or email for further assistance.

Precision Zone Repair Benefits for Okuma BLII-D AC Servo Drives

  • Free evaluation by expert technicians include:
    • Visual Inspection
    • Static Check
    • Power Tests
  • Free Job Estimate
  • 12 month warranty on our parts and labor
    Flat Price
  • Exchange Options
  • Rush Service Options

Contact Us To Start Your Repair Today!


Recently Repaired Products

Okuma BLII-D75-50A image BLII-D75-50A is an
Drives-AC Servo manufactured by Okuma
Discovered issues: Bad Control Section/Board, Bad Output Transistors/SCRs
Drive Type: 2-axis AC Servo Drive
Power Unit Capacity for First & Second Axes; control board: 75/50A (A006-0601)
Type: A

Okuma BLII-D50-50A image BLII-D50-50A is an
Drives-AC Servo manufactured by Okuma
Discovered issues: Bad Capacitor(s), Bad Circuit Board Component(s), Leaky Capacitors (Open, Corroded Traces)
Drive Type: 2-axis AC Servo Drive
Power Unit Capacity for First & Second Axes; control board: 50/50A (A006-0601)
Type: A

Okuma BLII-D50-30A image BLII-D50-30A is an
Drives-AC Servo manufactured by Okuma
Discovered issues: Bad Capacitor(s), Bad Circuit Board Component(s), Bad Gate Section/Board
Drive Type: 2-axis AC Servo Drive
Power Unit Capacity for First & Second Axes; control board: 50/30A (A006-0601)
Type: A

Okuma BLII-D75-75A image BLII-D75-75A is an
Drives-AC Servo manufactured by Okuma
Discovered issues: Bad Magnetic Contactor, Relay, Leaky Capacitors (Open, Corroded Traces)
Drive Type: 2-axis AC Servo Drive
Power Unit Capacity for First & Second Axes; control board: 75/75A (A006-0601)
Type: A

Okuma BLII-D100A image BLII-D100A is an
Drives-AC Servo manufactured by Okuma
Discovered issues: Bad Brake Transistor (Regen), Bad Circuit Board Component(s)
Drive Type: 1-axis AC Servo Drive
Power Unit Capacity: 100A
Type 1: A
Type 2: none

Okuma BLII-D75A image BLII-D75A is an
Drives-AC Servo manufactured by Okuma
Discovered issues: No Display
Drive Type: 1-axis AC Servo Drive
Power Unit Capacity: 75A
Type 1: A
Type 2: none

Okuma BLII-D30-30A image BLII-D30-30A is an
Drives-AC Servo manufactured by Okuma
Discovered issues: Physical Damage to the Drive
Drive Type: 2-axis AC Servo Drive
Power Unit Capacity for First & Second Axes; control board: 30/30A (A006-0601)
Type: A

Okuma BLII-D30A image BLII-D30A is an
Drives-AC Servo manufactured by Okuma
Discovered issues: Bad Capacitor(s), Bad Circuit Board Component(s), Leaky Capacitors (Open, Corroded Traces)
Drive Type: 1-axis AC Servo Drive
Power Unit Capacity: 30A
Type 1: A
Type 2: none

Okuma BLII-D50A image BLII-D50A is an
Drives-AC Servo manufactured by Okuma
Discovered issues: Bad Capacitor(s), Bad Circuit Board Component(s), Leaky Capacitors (Open, Corroded Traces)
Drive Type: 1-axis AC Servo Drive
Power Unit Capacity: 50A
Type 1: A
Type 2: none

Okuma BLII-D200A image BLII-D200A is an
Drives-AC Servo manufactured by Okuma
Discovered issues: Bad Capacitor(s), Bad Circuit Board Component(s), Leaky Capacitors (Open, Corroded Traces)
Drive Type: 1-axis AC Servo Drive
Power Unit Capacity: 200A
Type 1: A
Type 2: none

Okuma BLII-D150A image BLII-D150A is an
Drives-AC Servo manufactured by Okuma
Discovered issues: Bad Circuit Board Component(s), Leaky Capacitors (Open, Corroded Traces)
Drive Type: 1-axis AC Servo Drive
Power Unit Capacity: 150A
Type 1: A
Type 2: none

Okuma BLII-D30AD image BLII-D30AD is an
Drives-AC Servo manufactured by Okuma
Discovered issues: Leaky Capacitors (Open, Corroded Traces)
Drive Type: 1-axis AC Servo Drive
Power Unit Capacity: 30A
Type 1: A
Type 2: for tool changer

Okuma BLII-D30-30AD image BLII-D30-30AD is an
Drives-AC Servo manufactured by Okuma
Discovered issues: Bad Circuit Board Component(s)
Drive Type: 2-axis AC Servo Drive
Power Unit Capacity for First & Second Axes; control board: 30/30A (A006-0601)
Type: D

Okuma BLII-D75-30A image BLII-D75-30A is an
Drives-AC Servo manufactured by Okuma
Discovered issues: Bad Capacitor(s), Bad Gate Section/Board
Drive Type: 2-axis AC Servo Drive
Power Unit Capacity for First & Second Axes; control board: 75/30A (A006-0601)
Type: A