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
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On Sat, 28 Aug 2010 19:31:16 -0500, Ignoramus5734

The secret to lektrik stuff is magic smoke. If you let it out, it don't work no more.
Buy another on the bay.
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wrote:

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

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
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On Sat, 28 Aug 2010 19:45:53 -0500, Karl Townsend

It's no longer available via eBay. Here is another source: http://www.mez.co.uk/lucas.html
-- 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
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ROTFLMOA Got tears coming out of my eyes.
I used to own a british car with Lucas wiring. Triumph TR4a
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On Sun, 29 Aug 2010 04:50:25 -0500, 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
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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
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Karl Townsend wrote:

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
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wrote:

Good one. I used to earn my living working on british bikes, trying to keep the smoke in.
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On Sat, 28 Aug 2010 19:31:16 -0500, Ignoramus5734

Find out which chip it is..and what could have killed it. Normally chips dont get blackened without a serious serious issue.
Gunner
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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
Martin
Martin H. Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net "Our Republic and the Press will Rise or Fall Together": Joseph Pulitzer TSRA: Endowed; NRA LOH & Patron Member, Golden Eagle, Patriot's Medal. NRA Second Amendment Task Force Originator & Charter Founder IHMSA and NRA Metallic Silhouette maker & member. http://lufkinced.com /
On 8/28/2010 7:31 PM, Ignoramus5734 wrote:

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On Sat, 28 Aug 2010 21:22:24 -0500, "Martin H. Eastburn"

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

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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:

http://www.arcticsilver.com/products.htm http://www.arcticsilver.com/usa_resellers.htm
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Dan H.
northshore MA.
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Arctic Silver Thermal Epoxy. Do Google. Several vendors have it in stock. I've got a couple half tubes sitting on my desk.
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I bought some from Amazon - they have a vendor that sells it - but via Amazon. I get free shipping from the Big A - otherwise there are other vendors. IIRC, it is a Intel design/developed - maybe just approved.
I'm gluing a heat sink on my SATA drive chip. It burned up on the last motherboard in the shop.
And thanks for the input.
Martin
Martin H. Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net "Our Republic and the Press will Rise or Fall Together": Joseph Pulitzer TSRA: Endowed; NRA LOH & Patron Member, Golden Eagle, Patriot's Medal. NRA Second Amendment Task Force Originator & Charter Founder IHMSA and NRA Metallic Silhouette maker & member. http://lufkinced.com /
On 8/29/2010 10:32 PM, Bob La Londe wrote:

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Ignoramus5734 wrote:

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
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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
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wrote:

Did you follow the suggested wiring scheme?
http://www.a-m-c.com/download/manual/AMC_AnalogDrives_InstallManual.pdf
Paul
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Ignoramus5734 wrote:

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
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