[rotec]

Still playing with this LB15, Its just a hobby machine today, so I'm in no rush to spend big bucks on it. I recently got it running again after replacing a CRPII board.

But Im still having spindle (SDU) alarm issues. At first I could let the machine warm up by running at say 500 rpm and the spindle would jerk a little, hunt with occasional pulsing this would slowly subside and then once warmed up would get better and better then ultimately run all day with no issues.

But now this has now gotten progressively worse, to the point where I cant get it to rotate a 1/2 turn before it alarms.

The Fanuc spindle drive (A06B-6044-H018) show LED 8 and 4 lit = Alarm #12 "Over Current in the DC line". The manual states short in the output terminals / motor or Power transistor as the likely culprits.

I'd be happy for anyone to chime in with ideas on how to test the IGBT.

Thanks.

[rotec]

Update: Im actually getting more Fanuc Alarm #2 "excessive deviation of speed" "when the motor speed is largely deviated from the commanded speed"
I get Alarm 2 more that I get Alarm 8, which I haven't had since. I have two complete drives in unknown condition and the both give the same alarm #2, even when I swap boards.
Could it be the tach generator at the spindle motor?
Any help would be appreciated.