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Fanuc Alpha Power Supply Fault Codes

fanuc cnc

Fanuc Alpha Power Supply Fault Codes

These codes and troubleshooting apply to DC and AC Fanuc power supplies that begin with part number A06B-6077, A06B-6081, and A06B-6087. On the LED display for these units, a “-” will mean that the power supply is not ready while a “0” means that the power supply is powered up correctly. If it reads something other than these two then the power supply has an alarm that needs to be corrected. Below is the list of Fanuc Alpha Power Supply fault codes.

MRO Electric and Supply maintains a comprehensive stock of new and used FANUC Spindle Amps. If you need a replacement part, please call 800-691-8511 or email sales@mroelectric.com.

Alarms
AL-01: Overcurrent in the Main Power Module.
AL-02: Cooling Fan Stopped.
AL-03: The temperature of the main circuit heat sink has risen abnormally.
AL-04: The DC Voltage has dropped.
AL-05: The main Capacitor was not recharged within the specified time.
AL-06: The Input Power Supply is Abnormal.
AL-07: In the main circuit the DC Voltage is abnormally high

A common alarm on installation of a new alpha power supply is an AL-05.
If you have this alarm we recommend double-checking the bus bar connector at the top of the power supply to make sure it is fully connected. Be sufe to check out our article on FANUC Alpha Servo Troubleshooting as well as  FANUC CNC parts.

Troubleshooting Faults of Fanuc Alpha Servo Drives

fanuc cnc

Troubleshooting Faults of FANUC Alpha Servo Drives

This troubleshooting guide is in reference to Fanuc drives that begin with part number A06B-6079, A06B-6080, and A06B-6096 and is meant to help troubleshoot Fanuc alpha drive faults. If a drive status alarm appears on the 7 segment display, where the “-” refers to drive not ready (Waiting for an Emergency Stop signal to power up) and “0” refers to drive powering up correctly. Any other number or letter on this status display is an alarm code. One of the more common faults is an Alarm 8.i Here are some tips to check to see what the issue may be when an alarm comes up on your drive.

MRO Electric and Supply supplies and repairs a large number of FANUC Servo Drives. To request a quote, please call 800-691-8511 or email sales@mroelectric.com.

1 – Check the link: (A06B-6079 drives only). An A06B-6079 drive can give a fault if the S1 Link is in the wrong position, so check the S1 – JV Connections (Type A Interface) and S2 – JS Connections (Type B Interface). An incorrect setting will cause an Alarm “8”.

2 – Check the wiring: A L motor is wired in the lower terminals and an M motor is wired in the upper terminals, both as U/V/W/E. JV1B connected from the L command plug of the axis card, JV2B from the M command plug. JX1A connected from previous drive, JX1B connected to the next drive in the line. The last drive in the line has a terminator in JX1B. 24v/0v/ESP connected into CX1A from the previous drive, out of CX1B to the next drive in the line.

3 – Disconnect motor cable: Meggar the motor to check the readings.

4 – Power machine on Do this while it is in an emergency stop. The drive is faulty if an alarm occurs, expect a “-” reading.

5 – Release Emergency Stop: Power the machine up after releasing the stop. If an alarm occurs, power the machine off and remove motor wires U/V/W/E (Note – this is dangerous on a vertical axis, brake release, slide drops etc). Release Emergency Stop and power the machine up. The drive is faulty if the alarm occurs, expect “0” reading.

6 – An additional test can be performed for equally sized 6079/6080 amplifiers H201 SVM2-12/12          H301 SVM2-12/12/12 H203 SVM2-20/20          H302 SVM3-12/12/20 (L&M) H206 SVM2-40/40          H303 SVM3-12/20/20 (M&N) H208 SVM2-80/80          H304 SVM3-20/20/20 (L/M&N) The suspect axis can be run from the other amplifier in the drive ie X drives M amplifier, Y drives L amplifier. To do this swap round a – X & Y Motor cables U/V/W/E (at the drive) and b – X & Y Command cables (at the drive) (6096 requires parameters changing to swap X & Y round).

The drive is faulty if the alarm remains the same as before the test. For example Alarm “8” is reported on a 6079-H201 drive using JV connections Steps 1~5 above, have been performed and still alarm “8”. Remove the servo motor wires from the lower terminals and reconnect into the upper terminals, upper into lower. Remove JV1B and insert into JV2B, JV2B into JV1B. Retest the machine.

The drive is faulty if the same alarm occurs, ie alarm “8” The fault lies elsewhere on the machine if another alarm occurs, ie alarm “9”. In this example the drive has detected an overcurrent from the L axis, alarm “8” Swapping the cables over allowed a different amplifier to control the axis. An “8” alarm would remain if the same drive circuitry detected the overcurrent. A “9” would occur if the overcurrent was detected using the other drive circuitry in the amplifier and the fault would be caused externally from the drive.

Fanuc Spindle Alarms for Troubleshooting

A06B-6079-H106

Alarm # Led Display Content of FANUC SPINDLE Alarms
8 4 2 1

1

o

Motor Overheat

2

o

Speed deviates from commanded speed

3

o

o

Regenerative fault

6

o

o

Excess Motor Speed Analog

7

o

o

o

Excess Motor Speed Digital

8

o

Voltage higher than specified

9

o

o

Radiator for power semiconductor overheat

10

o

o

+15Volt Supply is low

11

o

o

o

DC Link voltage is high

12

o

o

DC Link current is high

13

o

o

o

CPU and peripheral parts are defective

14

o

o

o

ROM is defective

Alarm List for A06B-6044-Hxxx

Alarm List for the following Drives:

Alarm # Led Display Content of Alarms
8 4 2 1

1

o

Motor Overheat

2

o

Speed deviates from commanded speed

3

o

o

Fuse F7in DC link is blown out.

4

o

Fuses F1,F2,F3 for AC input blown out.

5

o

o

Fuses AF2 or AF3 on PCB are blown out.

6

o

o

Excess Motor Speed Analog

7

o

o

o

Excess Motor Speed Digital

8

o

Voltage higher than specified (24v)

9

o

o

Radiator for power semiconductor overheat

10

o

o

+15Volt Supply is low

11

o

o

o

DC Link voltage is high

12

o

o

DC Link current is high

13

o

o

o

CPU and peripheral parts are defective

14

o

o

o

ROM is defective

15

o

o

o

o

Option circuit fault.

Digital AC Spindle Drive

Alarm List for A06B-6055-Hxxx

Alarm List for the following drives:

  • Model 3 thru 22    A06B-6055-Hxxx

 

Alarm Display Alarm Content

AL-01

Motor Overheated

AL-02

Speed deviates from commanded speed

AL-03

Fuse F7in DC link is blown out.

AL-04

Fuses F1,F2,F3 for AC input blown out.

AL-06

Excess Motor Speed Analog

AL-07

Excess Motor Speed Digital

AL-08

Voltage higher than specified (24v)

AL-09

Radiator for power semiconductor overheat

AL-10

+15v power supply is abnormally low

AL-11

DC Link voltage is high

AL-12

DC Link current is high

AL-13

Data memory for CPU abnormal

AL-16

RAM in NVRAM is abnormal

AL-17

ROM in NVRAM is abnormal

AL-18

Check sum alarm of ROM

AL-19

Excessive alarm of U phase current detection circuit offset

AL-20

Excessive alarm of V phase current detection circuit offset

AL-21

Excessive alarm of velocity command circuit offset.

AL-22

Excessive alarm of velocity detection circuit offset.

AL-23

Excessive alarm of ER circuit offset.

AL-14

ROM is abnormal

AL-15

Spindle selection control circuit is abnormal.

Alarm List for A06B-6059-Hxxx

Alarm List for the following drives:

  • Model 1S thru 3S   A06B-6059-Hxxx

 View Fanuc Spindle Amp Alarm Codes for Alpha Series here. 

Alarm # Meaning

AL-01

Motor Overheat

AL-02

Speed deviates from commanded speed

AL-03

24v Fuse is blown. (before PCB edition 09A)

AL-04

AL-05

AL-06

Excess Motor Speed Analog

AL-07

Excess Motor Speed Digital

AL-08

Over voltage

AL-09

Overheat of radiator

AL-10

Low voltage of input power.

AL-11

Excessive high voltage of DC link

AL-12

Abnormal current of DC link

AL-13-15

AL-16-23

Defective arithmetic circuit and peripheral circuit

No indication

Defective ROM

Alarm List for A06B-6059-Hxxx

Alarm List for the following drives:

  • Model 6S-26S    A06B-6059-Hxxx
Alarm # Meaning

AL-01

Motor Overheat

AL-02

Speed deviates from commanded speed

AL-03

24v Fuse is blown. (before PCB edition 09A)

AL-04

Open phase of input power.

AL-05

AL-06

Excess Motor Speed Analog

AL-07

Excess Motor Speed Digital

AL-08

Over voltage

AL-09

Overheat of radiator

AL-10

Low voltage of input power.

AL-11

Excessive high voltage of DC link

AL-12

Abnormal current of DC link

AL-13

Defective arithmetic circuit

AL-14

Defective ROM

AL-15

Defective optional circuit.

AL-16-23

Defective arithmetic circuit and peripheral circuit

No indication

Defective ROM

Fanuc 911 RAM PARITY ERROR Troubleshooting

Fanuc 911 Error

Fanuc 911 RAM PARITY ERROR Troubleshooting

MRO Electric and Supply maintains a comprehensive stock of new and used FANUC CNC and FANUC Robots parts. If you need a FANUC replacement part, please call 800-691-8511 or email sales@mroelectric.com.

Last week we had a customer who was running an RNC 16 STAR 1990 vintage machine which failed so he decided to replace the main A16B-1010-0280 motherboard. His original problem was that he was receiving a 401 [VRDY Off] Error which then led to a 911 Error. When he replaced the A16B-1010-0280 motherboard, the machine would go directly to the 911 Error.

The first thing we checked for was to make sure that he transferred over all of the EEPROM modules from his original board to the replacement board, which he did. Since that wasn’t the issue, we double checked on the 911 Error, which shows as a RAM PARITY ERROR in the manual. The main cause of this error is an issue with the memory in the unit, which is caused by the memory board failing or losing the parameters in the system.

To check to see if the memory board was causing it or not, you can turn the control off, reset it, and delete the parameters. If this clears the alarm, the control would come up with a different series of servo alarms meaning that the parameters need to be reloaded. If the Fanuc 911 Error comes back it would mean that there is a problem with the memory board which needs to be replaced. Before trying any of this, be sure to confirm that you have all of the parameters saved so you can load them back in. Check out our article on IT and Robotics here.

Once the 911 Error was cleared, the customer was able to load the parameters back on to get the machine up and running.

Rebuild a Fanuc Motor – Model A06B-0131-B075 Process

Gallery of pictures showing the process that it takes to rebuild a Fanuc motor, part number A06B-0128-B675#7008.

Original pictures of the motor. Fan is dirty, all sides show significant use.

fanuc motor repair
fanuc motor repair

Upon disassembling the FANUC servo motor, the residue was found in the stator prompting the removal of the motor shaft. This would have caused a short in the stator once running.

The finished product, after the motor is rebuilt and fully tested.

rebuild a fanuc motor
fanuc servo motor repair
MRO Electric stocks new and refurbished FANUC CNC Motors. We also provide pre-priced Control Techniques repairs. For more information or to request a quote, please call 800-691-8511 or email sales@mroelectric.com.