Our Team Expertly Repairs Fanuc AC Digital Servo Drive

At Precision Zone, we specialize in Fanuc product repairs which include a wide range of AC Servo Drives. One of the many servo lines we service is the Fanuc AC Digital Servo Drive line.

The AC Digital Servo drive is the general servo offering from Fanuc which accepts control signals from the NC and then subsequently outputs a PWM control signal to accurately drive a servo motor. These digital servos come in 1, 2, and 3 axis offerings. The digital servo drive is indicated by part number A06B-6058 and the number of axes is indicated by the number following the ‘H’ in the part number.

These servos can be used with 0 series or 15 series control. The servo drive parameters are programmed through the NC control, but these units do contain indicator LEDs onboard for alarm and status display. The ‘C’ series servo amplifiers contain a seven-segment LED for drive status indication. The ‘S’ series servo amps have terminal settings that can be set onboard to indicate if a separate discharge unit is being used or if the thermostat signal is being connected. The ‘C’ series does not require these jumper settings.

Here at Precision Zone, we offer full support and testing on all A06B-6058 servo drives.

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

    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 have available 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 Fanuc Series AC Digital 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. 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 and 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.

Input

Positive Lead Negative Lead Reading
R Positive bus terminal 0.34V-0.4V
S Positive bus terminal 0.34V-0.4V
T Positive bus terminal 0.34V-0.4V
Negative bus terminal R 0.34V-0.4V
Negative bus terminal S 0.34V-0.4V
Negative bus terminal T 0.34V-0.4V

Output

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

The capacitor values on the PCBs are verified and any relays, contactors or circuit breakers in the drive are examined to ensure proper functionality.

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 Fanuc simulator. Alarms can be verified on the LEDs directly on the servo pack. See the list below for explanations of the various LED displays.

List of Alarms

S SERIES

LED Symbol Description
5V Green LED signals control power is on
DRDY Green LED Signals that PWM signal is available
HC High Current (Red) - Lights when excessive current crosses DC link
LV Low Voltage (Red) - Lights when regulator circuit malfuncions or when incoming power is excessively low
DC Discharge Alarm (Red) - Issue with discharge/regeneration circuitry
OH Overheat (Red) - Occurs when the signal from the thermostat contact is not present
FAL Fuse Alarm (Red) - Indicates a trip of F4 or F5

C SERIES (seven-segment LED)

LED Symbol Description
1 Overvoltage (DC link has exceeded 283VDC)
2 Circuit Power Under Voltage (+5V control circuit power has dropped below 4.6VDC)
3 Main Under Voltage Issue (with either DC voltage of main power supply dipping too low or +15V from power supply dropping under 10V)
4 Regenerative Circuit Abnormality (Regeneration circuit cannot fully handle the discharge energy. Possible short circuit with IGBT)
5 Excessive Regenerative Discharge Alarm (Occurs when average discharge energy is too high and can be caused by too frequent acceleration/deceleration or failing circuitry)
6 Overheat (Occurs when the signal from the thermostat contact is not present. Check to see if motor load exceeds rated current.)
7 Main Contactor Alarm (Occurs when main contactor welds shut – often caused by short circuit of input diode bridge)
8, 9, h Over current (Abnormally high current flows into the main circuit. Issue may be with motor grounding or abnormal PWM signal)

Precision Zone Repair Benefits for Fanuc AC Digital Servo Series

    1. FREE evaluation by expert technician includes:
    • Visual Inspection
    • Static Check
    • Power Tests
    2. FREE job estimate
    3. 12 month warranty on our parts and labor
    4. Flat Price
    5. Exchange Option
    6. Rush Service


Recently Repaired Products

Fanuc A06B-6058-H231 image A06B-6058-H231 is an
Drives-AC Servo manufactured by Fanuc
Discovered issues: Bad Capacitor(s), Bad Circuit Board Component(s)
Part Group: Motors and Drives
Series: AC Digital Servo Amplifier Module
Part Type: Drive
Number of Axes: 2-Axis
Motor Model: 31

Fanuc A06B-6058-H005 image A06B-6058-H005 is an
Drives-AC Servo manufactured by Fanuc
Discovered issues: Bad Circuit Board Component(s), Bad Load Sharing Resistor, Bad Output Transistors/SCRs, Bad Power Section/Board
Part Group: Motors and Drives
Series: AC Digital Servo Amplifier Module
Part Type: Drive
Number of Axes: Single-Axis
Motor Model: 05

Fanuc A06B-6058-H223 image A06B-6058-H223 is an
Drives-AC Servo manufactured by Fanuc
Discovered issues: Bad DCCT
Part Group: Motors and Drives
Series: AC Digital Servo Amplifier Module
Part Type: Drive
Number of Axes: 2-Axis
Motor Model: 23

Fanuc A06B-6058-H252 image A06B-6058-H252 is an
Drives-AC Servo manufactured by Fanuc
Discovered issues: Bad Capacitor(s)
Part Group: Motors and Drives
Series: AC Digital Servo Amplifier Module
Part Type: Drive
Number of Axes: 2-Axis
Motor Model: 52

Fanuc A06B-6058-H251 image A06B-6058-H251 is an
Drives-AC Servo manufactured by Fanuc
Discovered issues: Bad Output Transistors/SCRs
Part Group: Motors and Drives
Series: AC Digital Servo Amplifier Module
Part Type: Drive
Number of Axes: 2-Axis
Motor Model: 51

Fanuc A06B-6058-H224 image A06B-6058-H224 is an
Drives-AC Servo manufactured by Fanuc
Discovered issues: Leaky Capacitors (Open, Corroded Traces), Physical Damage to the Circuit Board/s
Part Group: Motors and Drives
Series: AC Digital Servo Amplifier Module
Part Type: Drive
Number of Axes: 2-Axis
Motor Model: 24

Fanuc A06B-6058-H006 image A06B-6058-H006 is an
Drives-AC Servo manufactured by Fanuc
Discovered issues: Bad Circuit Board Component(s)
Part Group: Motors and Drives
Series: AC Digital Servo Amplifier Module
Part Type: Drive
Number of Axes: Single-Axis
Motor Model: 06

Fanuc A06B-6058-H004 image A06B-6058-H004 is an
Drives-AC Servo manufactured by Fanuc
Discovered issues: Bad Circuit Board Component(s)
Part Group: Motors and Drives
Series: AC Digital Servo Amplifier Module
Part Type: Drive
Number of Axes: Single-Axis
Motor Model: 04