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Our Team Expertly Repairs Fanuc AC Spindle Units

Here at Precision Zone, one of our specialties is the repair services of Fanuc AC Spindle drive units.

Fanuc’s earlier AC Spindle units can still be found in Fanuc machines today! These units can be identified by part number A06B-6044 followed by a unique identifying code. These drives have alarm readouts displayed by 4 lamps on the top board and offer easily accessible check points for maintenance and troubleshooting. A switch allows for configurable input power depending if the source runs high or low. With easy installation and the ability to make adjustments directly on the drive, the A06B-6044 AC spindle drive units are versatile and powerful.

When assessing the functionality of a spindle 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 megaohm 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 Alpha Series AC Spindle 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

Input Module Testing

The input modules on these units can be tested by use of a digital multimeter with diode checking capabilities. Upon removing the cover, all of these terminals can be located along the terminal strip found within the unit.

Positive Lead Negative Lead Reading
R 'P' Terminal 0.30V-0.40V
S 'P' Terminal 0.30V-0.40V
T 'P' Terminal 0.30V-0.40V
'N' Terminal R 0.30V-0.40V
'N' Terminal S 0.30V-0.40V
'N' Terminal T 0.30V-0.40V

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 'P' Terminal 0.40V-0.42V
V 'P' Terminal 0.40V-0.42V
W 'P' Terminal 0.40V-0.42V
'N' Terminal U 0.40V-0.42V
'N' Terminal V 0.40V-0.42V
'N' Terminal W 0.40V-0.42V

List of Common Alarms for Fanuc AC Spindle Units

Number Alarm Display (LED Lit) Checks
1 LED 1
Motor Overheat
  • Check operating conditions of motor
  • Make sure motor fan is working properly
  • Ensure no dirt or debris has clogged the motor fan
  • Check motor thermistor
2 LED 2
Speed Deviation
  • Check if motor is overloaded
  • Verify encoder signals and connections
  • Check motor insulation with megger
3 LED 1, 2
Regenerative Circuit is Faulty
  • Check all braking resistors and regenerative units
  • Check motor cables and motor input for any failures with insulation
  • Check regenerative transistor
8 LED 8
Excessively High Voltage
  • Check incoming voltages
  • Verify that +24V voltage is correct and present

For further information on these, and all other alarms, please give us a call at (847) 465- 9060 or email us at repair@precisionzone.com.

Precision Zone Repair Benefits for Fanuc AC Spindle Alpha 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 Options


Recently Repaired Products

Fanuc A06B-6044-H208 image A06B-6044-H208 is an
Drives-AC Spindle manufactured by Fanuc
Discovered issues: Bad Input Diodes/SCRs, Bad Magnetic Contactor, Relay
Part Group: Motors and Drives
Series: AC Spindle servo unit
Part Type: Drive
Model: Model 8, external radiation type

Fanuc A06B-6044-H011 image A06B-6044-H011 is an
Drives-AC Spindle manufactured by Fanuc
Discovered issues: Bad Control Section/Board, Bad Cooling Fans
Part Group: Motors and Drives
Series: AC Spindle servo unit
Part Type: Drive
Model: Model 15, standard type

Fanuc A06B-6044-H130 image A06B-6044-H130 is an
Drives-AC Spindle manufactured by Fanuc
Discovered issues: Bad DC Bus Capacitors, Bad Magnetic Contactor, Relay, Leaky Capacitors (Open, Corroded Traces)
Part Group: Motors and Drives
Series: AC Spindle servo unit
Part Type: Drive
Model: Model 30

Fanuc A06B-6044-H212 image A06B-6044-H212 is an
Drives-AC Spindle manufactured by Fanuc
Discovered issues: Bad Gate Section/Board, Bad Output Transistors/SCRs
Part Group: Motors and Drives
Series: AC Spindle servo unit
Part Type: Drive
Model: Model 12, external radiation type

Fanuc A06B-6044-H021 image A06B-6044-H021 is an
Drives-AC Spindle manufactured by Fanuc
Discovered issues: Bad Fuse, Bad Precharge Resistor
Part Group: Motors and Drives
Series: AC Spindle servo unit
Part Type: Drive
Model: H021

Fanuc A06B-6044-H027 image A06B-6044-H027 is an
Drives-AC Spindle manufactured by Fanuc
Discovered issues: Bad Control Section/Board, Bad DC Bus Capacitors, Bad Gate Section/Board, Leaky Capacitors (Open, Corroded Traces)
Part Group: Motors and Drives
Series: AC Spindle servo unit
Part Type: Drive
Model: Model 22, external radiation type

Fanuc A06B-6044-H009 image A06B-6044-H009 is an
Drives-AC Spindle manufactured by Fanuc
Discovered issues: Bad Capacitor(s), Bad Circuit Board Component(s), Bad Gate Section/Board, Bad Magnetic Contactor, Relay, Bad Output Transistors/SCRs
Part Group: Motors and Drives
Series: AC Spindle servo unit
Part Type: Drive
Model: Model 6 high-speed, standard type

Fanuc A06B-6044-H112 image A06B-6044-H112 is an
Drives-AC Spindle manufactured by Fanuc
Discovered issues: Bad Circuit Board Component(s), Bad Output Transistors/SCRs
Part Group: Motors and Drives
Series: AC Spindle servo unit
Part Type: Drive
Model: Model 12, standard type

Fanuc A06B-6044-H008 image A06B-6044-H008 is an
Drives-AC Spindle manufactured by Fanuc
Discovered issues: Bad Capacitor(s), Bad Circuit Board Component(s), Bad Cooling Fans, Bad Fuse
Part Group: Motors and Drives
Series: AC Spindle servo unit
Part Type: Drive
Model: Model 6, standard type

Fanuc A06B-6044-H039 image A06B-6044-H039 is an
Drives-AC Spindle manufactured by Fanuc
Discovered issues: Bad Circuit Board Component(s), Bad Output Transistors/SCRs
Part Group: Motors and Drives
Series: AC Spindle servo unit
Part Type: Drive
Model: H039

Fanuc A06B-6044-H007 image A06B-6044-H007 is an
Drives-AC Spindle manufactured by Fanuc
Discovered issues: Bad Capacitor(s), Bad Circuit Board Component(s)
Part Group: Motors and Drives
Series: AC Spindle servo unit
Part Type: Drive
Model: Model 3, standard type