Dear Sirs

We were getting error 401 VRDY off for axis A and so drive A was not getting ready although all other drives were getting ready, we found problem in Servo Interface Card of CNC, replaced the same and then Machine became alright for about 6 jobs

Now error 401 appearing for all axes and it is not getting reset

We have checked incoming power supply to Fanuc PSM (Power Supply Module) , found to be alright


  • <LI class=MsoNormal style="COLOR: navy; mso-list: l0 level1 lfo1">We have disconnected Motor power cable from all the Servo Drives, still error 401 for all axes <LI class=MsoNormal style="COLOR: navy; mso-list: l0 level1 lfo1">We have replaced Fanuc Power Supply Module (PSM) , still error 401 <LI class=MsoNormal style="COLOR: navy; mso-list: l0 level1 lfo1">After sometime, without doing anything, we found that PSM and all other drives, except drive for A axis got ready that means all drives had 0 on display <LI class=MsoNormal style="COLOR: navy; mso-list: l0 level1 lfo1">We switched off and on, again we found that PSM and all other drives, except drive for A axis got ready that means all drives had 0 on display – this happened 5 to 6 times <LI class=MsoNormal style="COLOR: navy; mso-list: l0 level1 lfo1">Again none of the drives getting ON and just – appearing on display <LI class=MsoNormal style="COLOR: navy; mso-list: l0 level1 lfo1">We have replaced Fanuc Power supply of CNC with new one <LI class=MsoNormal style="COLOR: navy; mso-list: l0 level1 lfo1">We have checked cable continuity of JV1,2,3,4,5,6 etc from Servo Drive to Main Board and Option board found alright
  • 3 Phase supply to machine is alright

Kindly let us know what else could be checked for 401 for all axes, please let us know how for about 5 to 6 times PSM and all other drives, except drive for A axis got ready that means all drives had 0 on display – this happened 5 to 6 times and then none getting ready

Sir do us suspect Option board which is connected with A and U axes and Main Board which gives command (JV) to other 4 axes ??????

Sir, is there any way to bypass axis to check which axis/drive is faulty due to which other drives also not may not be getting ready ???????

Kindly advice

Best Regards,

M. Rishikesh


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