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

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.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.