Author Topic: Product Teardowns and EOS/ESD  (Read 4654 times)

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Offline JohnS_AZ

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Product Teardowns and EOS/ESD
« on: May 20, 2011, 05:26:26 pm »
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
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Online EEVblog

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Re: Product Teardowns and EOS/ESD
« Reply #1 on: May 21, 2011, 03:20:55 am »
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.

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.

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.

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.

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.

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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.

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.
« Last Edit: May 21, 2011, 03:45:19 am by EEVblog »
 

Offline PetrosA

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Re: Product Teardowns and EOS/ESD
« Reply #2 on: May 21, 2011, 01:19:10 pm »
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.
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Offline stl

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Re: Product Teardowns and EOS/ESD
« Reply #3 on: May 21, 2011, 05:12:15 pm »
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  :)
 

Offline JohnS_AZ

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Re: Product Teardowns and EOS/ESD
« Reply #4 on: May 21, 2011, 05:15:24 pm »
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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Offline Mechatrommer

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Re: Product Teardowns and EOS/ESD
« Reply #5 on: May 22, 2011, 02:06:06 am »
i understand John's point since his Arizona is the place where all the floating electrons gather and do the party. and the rest of the globe maybe dont have a clear idea about that.
if something can select, how cant it be intelligent? if something is intelligent, how cant it exist?
 

Online EEVblog

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Re: Product Teardowns and EOS/ESD
« Reply #6 on: May 22, 2011, 02:25:51 am »
Professionally, however, I stand by my comments and respectfully disagree.

I would agree with you, hence why I've done a blog on ESD, and will probably do more on the proper implementation of ESD.
However, this isn't a professional scenario where I am trying my best not to damage the product. It's a review, where I'm actually doing the opposite and TRYING to fault the product under question, using what I think is quite a realistic user scenario.

Dave.
 

Online EEVblog

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Re: Product Teardowns and EOS/ESD
« Reply #7 on: May 22, 2011, 02:35:23 am »
People are "shocked" because not wearing a wristband is politically incorrect

And of course politically incorrect is what I do so well! ;D

I agree with everyone's comments about proper ESD protection 100%, it's just that they don't seem to "get it" when it comes to this unique review type situation. They are just blanket applying their learned "not using an ESD strap is bad" mentality without considering what is trying to be achieved here.

Just look at the fault in the new Agilent meter that seems to be caused by a dicky range switch and firmware (see new video from Satuation now embedded in the blog post). People can argue that it's not realistic to expect the meter not to lock up when the meter switch is held half way between ranges. But well, it is indicative of a major problem and must be fixed. Could be the same if a meter PCB died due to basic handling without an ESD strap IMO.

Dave.
 

Offline the_raptor

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Re: Product Teardowns and EOS/ESD
« Reply #8 on: May 22, 2011, 04:33:27 am »
People can argue that it's not realistic to expect the meter not to lock up when the meter switch is held half way between ranges.

Well it isn't realistic. However the meter ISN'T locking up it is giving out random/uncalibrated readings, which is unacceptable of equipment designed to measure lethal levels of electricity.

In general engineering practice it is never acceptable for a device to get into an unknown state due to not verifying user input. The meter is not failing SAFE.

This is similar to that other meter you reviewed dave that was giving wonky readings when low on battery and had to be recalled.
 

Online EEVblog

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Re: Product Teardowns and EOS/ESD
« Reply #9 on: May 25, 2011, 01:22:56 am »
Well it isn't realistic. However the meter ISN'T locking up it is giving out random/uncalibrated readings, which is unacceptable of equipment designed to measure lethal levels of electricity.

It did lock up as well, you can see that in my video.
I'm sure you can get the thing to whistle dixie if you fiddle with it enough. The meter has some serious problems.

Dave.
 


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