Servo drive failed

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
Reply to
Ignoramus5734
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The secret to lektrik stuff is magic smoke. If you let it out, it don't work no more.

Buy another on the bay.

Reply to
Karl Townsend

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

Reply to
co_farmer

Find out which chip it is..and what could have killed it. Normally chips dont get blackened without a serious serious issue.

Gunner

I am the Sword of my Family and the Shield of my Nation. If sent, I will crush everything you have built, burn everything you love, and kill every one of you. (Hebrew quote)

Reply to
Gunner Asch

It's no longer available via eBay. Here is another source:

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-- If we attend continually and promptly to the little that we can do, we shall ere long be surprised to find how little remains that we cannot do. -- Samuel Butler

Reply to
Larry Jaques

I just replaced my shop computer motherboard because of one chip failed. The Disk controller for SATA drives got a hot corner. The temp here has been hot, but I try not to use it when I don't have refrig air blowing on it.

It started telling me bad disk drive. Force reformat and re-install - only to die. Buy a brand new disk - that one failed likewise. Hum - bit issues.

New mother board, both disks format and function as they should.

It was the only LSI chip there without a heat sink. Now a INTEL motherboard is in and sigh - looks like I'm looking for heat sink epoxy.

Anyone know of any easy to find without buying gold-epoxy ?

No mounting holes for a sink - and I think one will help.

I have a HD screen - with dual inputs - Got a low cost HD video card - and wow is that nice to look at now!

Martin

Mart> Since yesterday, I had the Z axis behaving very weirdly, suddenly lots

Reply to
Martin H. Eastburn

Why not just put a small fan in the case aimed at the chip?

I am the Sword of my Family and the Shield of my Nation. If sent, I will crush everything you have built, burn everything you love, and kill every one of you. (Hebrew quote)

Reply to
Gunner Asch

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

Reply to
Spehro Pefhany

Whose servo amp? Can you tell by location what that chip is connected to? Check another to get the part number of the burned chip.

Jon

Reply to
Jon Elson

That was am AMC 30A8 amplifier, revision T.

The chips on them mostly do not have markings, this one was a small one in the middle of the motherboard.

I really like the drives, their simplicity, cost and support from AMC. I do not know if I can guess the cause. But, possibly, interference again is to blame. I have, since, routed the twisted DC motor cables away from control stuff.

You mentioned ferrite cores to place on these cables. Would you suggest any particular Digikey part number?

Thanks

i
Reply to
Ignoramus5734

What's that Lassie? You say that Martin H. Eastburn fell down the old rec.crafts.metalworking mine and will die if we don't mount a rescue by Sat, 28 Aug 2010 21:22:24 -0500:

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Reply to
dan

Ignoramus5734 on Sat, 28 Aug 2010

19:31:16 -0500 typed in rec.crafts.metalworking the following:

Ah, it sounds like you let the magical smoke out of the chip. That's the real secret of electronic equipment, it really runs on smoke. Just don't let the smoke catch fire. That's ...bad.

You might want to "add more fans" in order to increase airflow, and hopefully cooling.

Reply to
pyotr filipivich

ROTFLMOA Got tears coming out of my eyes.

I used to own a british car with Lucas wiring. Triumph TR4a

Reply to
Karl Townsend

Ever, perchance, have a grounding problem wi that wee beastie, Karl?

-- If we attend continually and promptly to the little that we can do, we shall ere long be surprised to find how little remains that we cannot do. -- Samuel Butler

Reply to
Larry Jaques

i owned that car four years. it was under repair for two of those years. AND it was my only car. I about split a gasket over the official lucas three way switch - dim,flicker, off. I put in all new wires for the starter and iginition. The rest of it normally didn't run.

karl

Reply to
Karl Townsend

Did you follow the suggested wiring scheme?

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Paul

Reply to
co_farmer

Arctic Silver Thermal Epoxy. Do Google. Several vendors have it in stock. I've got a couple half tubes sitting on my desk.

Reply to
Bob La Londe

I rebuilt several TR3's in my youth. Saved the cable to the starter motor and battery ground cable, and most of the switches, etc, especially ignition switch, headlight switch and dimmer switch. Pretty much everything else had to go, and totally rewired everything with that new-fangled plastic-covered wire. With the cloth-covered wire, exposed to oil and moisture, the stuff just disintegrated completely.

Jon

Reply to
Jon Elson

VERY unlikely.

Sorry, I really don't have a part number. You might check old computer cables for those bulges in them, those are big ferrite rings for noise isolation. You want to run both motor cables through the same core, so they are not exposed to the motor current (the current in the two wires cancels out).

Jon

Reply to
Jon Elson

Agree.

The split-sleeve emi-filter chokes are what Iggy seeks. Here is an example:

However, these chokes really are not that effective compared to real shielding. I would first shield the motor power leads, as they are very high power.

Joe

Reply to
Joseph Gwinn

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