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Product Teardowns and EOS/ESD

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JohnS_AZ:
Hi Dave,

Just watched the Agilent U1272A Fail video, read the comments on YouTube, and the thread here on the forum. For the first time I have to take exception to something that you said.

Not wearing a wrist strap during a teardown because the average Joe wouldn't, and considering it a test of robustness is just plain silly. That's like saying you're going to evaluate a car by running it with no oil in the engine. The EOS/ESD protections built into a product INCLUDE the case being present and properly assembled. Once that PCB is exposed all bets are off.

Now I am not saying that you zapped the thing, but by not wearing a proper wrist strap you allow that question to come into play. In other words, by not wearing a strap the ESD questions are valid, and if you do wear a strap any ESD questions are precluded. Presuming the point of teardown videos are to focus on the product in question, and not on your bench procedures, I would consider a wrist strap to be essential in all teardowns. Further, in the event a product does fail, observing ESD precautions will eliminate that possible cause from the troubleshooting that may happen later.

As for the nit-wits who would say you need an ionizer and all the other gear, that's nonsense. A good grounded mat, a good grounded wrist strap, keep the area clear of stuff that can hold a charge, and you're golden.

Keep'em coming. I anxiously await each new video!
@JohnS_AZ

EEVblog:

--- Quote from: JohnS_AZ on May 20, 2011, 05:26:26 pm ---Not wearing a wrist strap during a teardown because the average Joe wouldn't, and considering it a test of robustness is just plain silly.

--- End quote ---

Not the way I see it.
Fact is it is incredibly common for people to take apart stuff without proper ESD precautions, and I am simply emulating that.
At least I'm using a proper mat which is more than most people would use when having a sticky beak inside something.

Is it actually a test of robustness?
Well, not really, that's a bit of throw-away line, but if I DID kill something (never have in 30+ years that I can recall, instant or long term) then that just might be indicative of a potential problem or weak point with the design. That would be a GOOD thing to find in my view.

I drop the damn things on the concrete floor, so why shouldn't I open it without an ESD strap as many potential people would?


--- Quote ---That's like saying you're going to evaluate a car by running it with no oil in the engine. The EOS/ESD protections built into a product INCLUDE the case being present and properly assembled.

--- End quote ---

I don't care what something is designed for, I think it's fun (and often telling) to go beyond that and see what happens.


--- Quote ---Once that PCB is exposed all bets are off.

--- End quote ---

Good, that's the way I like it.
People LIKE me abusing the meters a little and see what happens. No different with ESD precautions.
I think treating these things with kid gloves is a bit lame.


--- Quote ---Now I am not saying that you zapped the thing, but by not wearing a proper wrist strap you allow that question to come into play. In other words, by not wearing a strap the ESD questions are valid, and if you do wear a strap any ESD questions are precluded. Presuming the point of teardown videos are to focus on the product in question, and not on your bench procedures, I would consider a wrist strap to be essential in all teardowns. Further, in the event a product does fail, observing ESD precautions will eliminate that possible cause from the troubleshooting that may happen later.

--- End quote ---

ESD straps and mats are not magic, using them does NOT eliminate the ESD question entirely.
Yes, the ESD questions were valid, I even raised it myself in the video as a remote possibility. But as it turns out (unsurprisingly) it has nothing to do with ESD as other people have the exact same problem.


--- Quote ---As for the nit-wits who would say you need an ionizer and all the other gear, that's nonsense. A good grounded mat, a good grounded wrist strap, keep the area clear of stuff that can hold a charge, and you're golden.

--- End quote ---

Actually, no, they would indeed have a valid point.

At some companies I've worked for that take ESD seriously it was instant dismissal if you didn't wear your lab coat or check your ESD strap every time you used it.

Seriously, ask yourself this:
If I didn't use an ESD strap and the meter failed due to ESD in a teardown, would you seriously say "that's ok, that's perfectly normal, it was never designed for that so it's nothing to worry about, it was bad practice" and just dismiss it as natural consequence of not taking full ESD precautions?
Yet every other meter (not to mention other gear) I've done the exact same thing to passes the handling with flying colours.

The whole backyard computer and one-hung-low product industry is built on handling exposed boards without full ESD protection. So if a quality designed piece of big name test gear failed under the same (actually, much better with my proper ESD mat) handling conditions, quite frankly I'd be a tad concerned, and so should you and the manufacturer...

Dave.

PetrosA:
I'm going to side with Dave on this one, at least for handheld DMMs. Many of them have to be opened to replace fuses and it would be asinine to assume that the user will have a wrist strap and anti-static mat in the field. Even the designs with exposed fuses will have large metal areas exposed with the battery/fuse cover removed.

stl:
In my opinion the PCB's have to be prepared to deal with ESD and see no problem that the tear-down was made without the wristband. Nevertheless Dave is working on top on a grounded ESD mat, and frequently touching it, so I would be very surprised if he zapped anything on those conditions witch are by far better than the ones field technicians have.

There are several factors we have to consider when dealing with ESD, being the relative humidity of the air the most important, but considering the "real life" conditions VS the ideal conditions I think the the tear-down was safe enough...

People are "shocked" because not wearing a wristband is politically incorrect, it's like if Dave start smoking during the tear-down. Do has I say, don't do has I do  :)

JohnS_AZ:
Well, the bottom lines is; Dave's blog, Dave's rules. As it should be. 8-)

Professionally, however, I stand by my comments and respectfully disagree.

@JohnS_AZ

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