fanuc 6m 421 alarm

[actionman]

Kitamura 1982 or so
I get intermittent 421 y servo alarm
i took the covers off and ran it no tool and ran fine
It seems right when I have a job to do
it alarms
any Ideas

Thanx
Joe

[actionman]

It also seems that when the alarm happens, and I reset
if I don't touch the ballscrew it will alarm again.
If I turn the screw by hand (even an 1/8 turn ) it will go ,as in home Y
There is also no binding that I can feel when I turn screw by hand
thanx
Joe

[Indmach]

I had a little smash on Z axis on daewoo puma 6 m control now I canot get away with 420 or 421 alaram machine worked fine

[Indmach]

Originally Posted by actionman It also seems that when the alarm happens, and I reset if I don't touch the ballscrew it will alarm again. If I turn the screw by hand (even an 1/8 turn ) it will go ,as in home Y There is also no binding that I can feel when I turn screw by hand thanx Joe

It might be your cover they are giving load to the ball screws
it might be your gibbs are loose or too tight and they are giving errors to Y axis servo
check the limit swithes make sure there are no chips there