Fun with ESD (Electrostatic Discharge)

[wwillson]

I have a couple Raspberry Pi 5 single board computers with NVMe hats. NVMe is light years faster, higher capacity, and more durable than micro SD. I built both of them last spring and they ran flawlessly until early winter when the NVMe drives started becoming unreachable on the bus. The only way to get back to a normal state is hold the power button down until it reboots, because without access to the NVMe drive, the OS can't read the "shutdown" command.

I upgraded drivers, NVMe firmware, etc. but nothing helped. I was a bit puzzled so I used a life-line and called my former coworker who is incredibly knowledgeable on all things electronics and electricity. He suggested I have an ESD problem, then told me some stories about very weird VAX problem he saw and the even stranger way their figured out it was ESD. Like every time one systems admin woman wore a red knit sweater and she touched the keyboard, the main storage drive would suffer corruption. He suggested I get a grounding kit and properly ground the Raspberry Pi metal cases to earth ground. I also got a ESD mat to set them on which is grounded.

I grounded everything properly and have a grounded wrist strap that I put on before touching anything. For the last week since I all the grounding was installed there has been zero problems. I think my friend is correct that I had an ESD problem.

 

[Jdeere562]

I have no idea of what you just said.
Maybe ignorance is bliss.

 

[JimPghPA]

Residue soap film is good at conducting enough to prevent static electric buildup.

Many moons ago, when mosfet transistors were first available to the public, they came without internal protection. A slight static discharge could destroy all of them in a circuit.

One EE saw that some racks of glass utility power meter covers did not have any dust on them, when other racks that were sitting around about the same amount of time had dust. So that EE investigated, and found that one person did not rinse those glass covers after washing them. The dried soap film conducted enough to prevent static buildup.

Using that knowledge, it became common practice to spray soapy water in electronic assembly areas and let it dry to leave a soap film.

Radio-Shack even sold an Anti-Static spray that was just an overpriced finger pumped spray bottle of soapy water.

 

[AZjeff]

I have no idea of what you just said.
Maybe ignorance is bliss.

Me too. I think he spilled raspberry pie on his keyboard...

 

[y_p_w]

At one of my first jobs I decided to get ESD certified. Watched a video and ended up getting a couple of blue ESD smocks with my name on them. But for the most part over my career I don't remember much that was really done caring about ESD. Most of the places I worked at the labs didn't have ESD straps and those working in the lab were wearing whatever clothes they would wear at a desk.

 

[Variant_S]

VAX? That takes me back.

I used to take annual ESD training. I think that I still have a wrist strap around here somewhere.

 

[SwampSurvivor]

ESD is some crazy stuff. At my last job I'd get calls randomly that someone's monitors would go out. I would ask them if someone near them got up or sat down recently. I'd get a bit of a wiseass answer from them but it was always yes. Okay, watch when they get up again. Your monitors will go out.

It was either someone's feet moving across the carpet as they moved to get up and getting shocked or the gas tube in the chair, but it would create ESD and knock out random monitor display adapters aroudn the office. Craziest stuff.

 

[Pew]

That's interesting.... I've been having a similar problem of late with my PC taking much longer on a cold boot but only after I wore wool socks and pants and zapped the PC a couple times (open case). I also zapped the cats a lot in the past week or so when petting them. The problem kind of went away this week with the weather getting warmer. Coincidentally the 24H2 update was at the same time.

 

[JimPghPA]

ESD can occure easier if the air is very dry.

Indoor air can often be dry in cold weather. So using humidifiers reduced the chance of ESD damage.

 

[y_p_w]

ESD is some crazy stuff. At my last job I'd get calls randomly that someone's monitors would go out. I would ask them if someone near them got up or sat down recently. I'd get a bit of a wiseass answer from them but it was always yes. Okay, watch when they get up again. Your monitors will go out.

It was either someone's feet moving across the carpet as they moved to get up and getting shocked or the gas tube in the chair, but it would create ESD and knock out random monitor display adapters aroudn the office. Craziest stuff.

Soft errors (aka "bit flip") might be of more concern than permanant damage to electronics.

At one of my jobs, our primary electronic product came in close contact with people. Small ESD events could lead to crazy things happening such as "latchup" where the biases could change and it was effectively two amplifiers with a positive feedback loop that could lead to overcurrent and possible meltdown.

 

[spackard]

Trust me, give it 10 minutes. You will be entertained, and informed. Dan C Anderson

 

[supton]

But for the most part over my career I don't remember much that was really done caring about ESD.

I see plenty of caution but myself I usually don't worry too much. Most devices have a few kV of ESD protection and once on a board, the board itself does something (usually good) for protection. I kinda/sorta want to see if ESD causes problems, if it does, then I know I need to redo my board and make it more robust.

But for the most part, a bit of protection goes a long ways. Conductive floors, bit of humidity, and some attempt at ESD footstraps etc.

 

[wwillson]

Not one issue since I properly grounded the Raspberri Pi SBCs. The air here runs about 15% humidity which absolutely contributes to the ESD problem.

The video above that @spackard posted is fantastic.

 

[y_p_w]

I see plenty of caution but myself I usually don't worry too much. Most devices have a few kV of ESD protection and once on a board, the board itself does something (usually good) for protection. I kinda/sorta want to see if ESD causes problems, if it does, then I know I need to redo my board and make it more robust.

But for the most part, a bit of protection goes a long ways. Conductive floors, bit of humidity, and some attempt at ESD footstraps etc.

Theoretically, the worst case scenario is with loose parts handled by people. But there's a lot done to minimize this including metalized parts bags and sleeves that are conductive. Back when I was working on a TTL design project, a lot of parts we got came in these conductive foam sheets.

 

[supton]

Theoretically, the worst case scenario is with loose parts handled by people. But there's a lot done to minimize this including metalized parts bags and sleeves that are conductive. Back when I was working on a TTL design project, a lot of parts we got came in these conductive foam sheets.

Those sheets are still around but I see few of them, most stuff is now SMT and on nice little bits of a reel. I think at one time some of the foam sheets interacted with leads and caused problems, actually. Tubes are nicer but with the switch to SMT it's all on reels that the PnP machine can handle.