On Aug 28, 5:45*pm, Karl Townsend
wrote:
On Sat, 28 Aug 2010 19:31:16 -0500, Ignoramus5734

wrote:
Since yesterday, I had the Z axis behaving very weirdly, suddenly lots
of chatter and vibration, extremely erratic behavior, then no motion
at all, then some motion etc.

Attempting to diagnose it (isolate the issue) pointed to a servo drive.

Since I have several additional drives on the shelf (they were cheap),
I swapped one for another. Now the Z axis is back to working. I opened
up the drive that I relpaced and saw one chip blackened.

Not sure what to make of this.

i

The secret to lektrik stuff is magic smoke. If you let it out, it
don't work no more.

Buy another on the bay.

Unlike individual transistors, ICs usually die from their own internal
problems. Usually too much heat and not enough heat sink. Can you
determine the Id of the victim?

Paul