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IndustryArena Forum > Machine Controllers Software and Solutions > Fanuc > 401 servo alarm (VRDY OFF), at turn on, Fanuc OM SOLVED
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  1. #21
    Join Date
    Jun 2013
    Posts
    4

    Re: 401 servo alarm (VRDY OFF), at turn on, Fanuc OM SOLVED

    i have 401alarm on fanuc om.with x,y,z axis.with shorting 7 and 13 pin on z drive connectori get 404 no alarm.

  2. #22
    Join Date
    Dec 2019
    Posts
    4

    Re: 401 servo alarm (VRDY OFF), at turn on, Fanuc OM SOLVED

    Today also same problem I faced. So found MCC circuit was break . So when this alarm will come then emergency circuit & MCC circuit should be check. Thanks.

  3. #23
    Join Date
    Sep 2007
    Posts
    27

    Re: 401 servo alarm (VRDY OFF), at turn on, Fanuc OM SOLVED

    I too am having 401 alarm on OT control. Usually at power on. I need to hit E stop and the reset and it usually clears. It must be a relay. I can hear something click if it works correctly. Sometimes I have to do it twice.
    Today, had it while running a program, everything stopped and 401 on screen. I cleared it the same way. Very odd, it lost tool position and turret changed to different position than called for on program. Lost a boring bar as is wacked the chuck. Everything seems OK. I zero'd the turret and now it seems fine. This is getting scary. My workshift 0 did not change either.
    I did replace the large "motherboard" (PCB A20B-1003-0864-R) on the machine a 5 years back for same reason. I haven't had this alarm for years, but back now.

  4. #24
    Join Date
    Jul 2017
    Posts
    50

    Re: 401 servo alarm (VRDY OFF), at turn on, Fanuc OM SOLVED

    Next time you get this alarm, check the servo amplifiers in the control cabinet for an alarm number on the 7 segment LED. This should help narrow down what the actual problem is.

  5. #25
    Join Date
    Sep 2007
    Posts
    27

    Re: 401 servo alarm (VRDY OFF), at turn on, Fanuc OM SOLVED

    Can deal with the alarm, cannot deal with turret position changing. I'll try your suggestion.

  6. #26
    Join Date
    Sep 2007
    Posts
    27

    Re: 401 servo alarm (VRDY OFF), at turn on, Fanuc OM SOLVED

    Powered up yesterday, no issue and ran machine all day. Today I got the 401 alarm at power up. I had the rear cabinet open and was watching the 7 LED. There is also a green LED above and below all the red ones. None of the red ones light up in 401. However, as it goes through power up, the lower is green lights up and stays lit, then you can hear some sort of relay kick in, that's when the upper green LED lights up. But if it goes into 401, the upper lights, but then turns off, as if the relay didn't catch. Upper green goes on, then out. Hit Estop, then reset button, it then clicked in. Both upper and lower green on, no 401. Again, no red LED's on, ever.
    I replaced this entire unit with another one from Fanuc, looks like 3-4 years ago. I believe I was having the same issue back then. Now it's back.

  7. #27
    Join Date
    Sep 2007
    Posts
    27

    Re: 401 servo alarm (VRDY OFF), at turn on, Fanuc OM SOLVED

    So today, 401 at power up. Same result as above. Top green LED lights for a second, then goes out. Hit E stop, then E stop reset, everything is good. Ran machine for 5 hours in a repeat cycle. Found it in a 401 alarm. Opened door and turret is seated as it should be, but in between two stations. This machine does not have that capability, so I reset Estop as I did in powerup, then zero the turret. Doubled checked, it's good to go, for now.
    When powering up and checking back of machine 7 LED, when that top one lights, you can hear a relay clicking in. Relay seems to let loose when it goes out. Find it odd I'm having the same issue with different board, but it took 5 years.
    Any thoughts, please reply.

  8. #28
    Hello good afternoon I have the alarm 401 servo alarm VRDY OFF present in all the axes of x, z, and head 1 and z, x head 2 of my fanuc 18i-T control I would appreciate if someone can guide me to repair this problem

  9. #29
    Join Date
    Sep 2007
    Posts
    27

    Re: 401 servo alarm (VRDY OFF), at turn on, Fanuc OM SOLVED

    I haven't had any response to my issue, so I'm just dealing with it.

    Yours looks more complicated. Maybe entire board, but it's also 18-T control. I have an O-T control. Try calling hardinge, you might get lucky.

  10. #30
    Join Date
    Aug 2019
    Posts
    1

    Re: 401 servo alarm (VRDY OFF), at turn on, Fanuc OM SOLVED

    NOTHING TO WORRY IS JUST A SIMPLE SOLUTION. CHECK THE CABLES FOR LOOSE CONNECTION. NEXT CHECK CONNECTION FROM TRANSFORMER INSIDE THE MACHINE PANEL. I TOO HAD THE SAME PROBLEM IN TECHNO WASINO JUST SOLVED IT IN 30 MINUTES BY CHECKING ENCODER CABLE AND ALL CONNECTION. I AM DAM SURE THERE WILL BE LOOSE CONNECTION. CHECK AND REPLY ME SIR MY CONTACT NO : +91 82700 08803 STALLIN.R.K

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