On Sat, 28 Aug 2010 18:19:21 -0700 (PDT), the renowned
" wrote:

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

All common CMOS chips have a giant parasitic SCR living inside them..
hit it with some static electricity and it can turn on and the chip
will destroy itself if there is enough power supply current available.
The term is "latch up". Modern chips are much more resistant than
older ones, but it can still happen.

Good designs protect the chips from obvious things like connectors
that go to the outside world using external parts (resistors, discrete
transistors, optoisolators that sort of thing), but if a part is
touched on a powered board it can die.


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
Info for manufacturers: http://www.trexon.com
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