View Full Version : Problem Fanuc Alarm 401

09-01-2013, 04:39 PM
I got an old YAM MV-3A NC milling with Fanuc OM-C control. When I start the machine the screen shows 401 Alarm "VRDY signal turned off". I checked out the servo cards, they seem to be ok, no red LED. Tha servo cards are powered at 220 VAC (terminals R, S, T), but there is no output signals at terminals (5, 7), The diagnostics screen show no problem with ESTOP signals.
The machine was unused for four years, eventhough the memorie batt is ok. I knew that some guy tried to work it but he could not. The reseller told me that is a problem with parameters.
I'll aprecciate any idea or suggestion.

09-02-2013, 10:23 AM
You might have better luck getting this question answered in the Fanuc forum.


09-02-2013, 12:02 PM
The 401 stands for X axis , check the X axis drive PCB and Voltage also check the parameters of x axis

09-02-2013, 01:56 PM
Possibly you can try here: CNC Alarms (http://www.webmachinist.net/cncalarms.html)

ies fixs
11-02-2013, 09:31 PM
International Electronic Solutions repairs Okuma drives and motors. Industrial Repair Service| Repair industrial equipment, Kollmorgan servo motor repair, ac motor repairs - International Electronic Solutions (http://www.iesrepairs.net). 1-855-437-3497. That Fanuc 401 alarm could be many different things such as the main bd, spindle drives, etc