michael.b133
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ESD Causing Restarts

Dec 08, 2018 10:49 pm

I have a kit Mk3, it's pretty new (~2kg through it) so this might be an issue I brought upon myself in the assembly, but...

Any time I shock myself on the printer frame, it causes the current print to restart, often times with a power fail detection beep. It tries to recover the print but more often than not it doesn't recover properly and the print is lost. For now, I've taken off the power supply and sanded some of the frame by the mounting screws down to bare metal, and it seems to have helped.

I was wondering if anyone else has had the same issue?

Also, I noticed that the power panic board had a provision for a 0v connection that was left off. I assume it's connected through the black wire that goes back to the einsy. Does anyone know why the extra wire was left off? If the issue is coming from the power panic board, it might help to connect it to the power supply directly, just to give it a more solid ground reference.

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joan.t
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Re: ESD Causing Restarts

Dec 08, 2018 11:32 pm

Hi Michael,

It may be you that is shocking the printer,

Do you have an anti static lead or piece of earth potential metal, in the vicinity of the printer that you can touch before you touch the the printer?

regards Joan
I try to make suggestions that I believe to be well founded and safe,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions,
what you do, is YOUR responsibility.

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tim.m30
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Re: ESD Causing Restarts

Dec 09, 2018 12:53 am

The power supply case is connected to earth by the power cord. You can try touching the bare aluminum power supply case first ... but even that can cause odd things to happen in the vicinity.

The best cure - before you fry something - is to buy heel or wrist straps.

https://www.amazon.com/Static-Bracelet- ... B073SGDDFD
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michael.b133
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Re: ESD Causing Restarts

Dec 09, 2018 1:19 am

Sorry, I should have clarified, it's certainly me that's carrying the charge. I tested the issue and my solution to it by dragging my feet across the carpet and touching the printer.

Mostly, I was curious if other people have had issues (sounds like they have). I was also concerned that I missed a step in the assembly, because it seems like the frame wasn't grounded.

I'm.. wait for it... shocked that the solution here is to use a wrist strap and/or observe ESD precautions typically used on bare PCBs or dissessembled products. I understand that it's not a true 'consumer' device like my TV or laptop, but I don't think it's that difficult to properly ground things and avoid these issues altogether. At the end of the day that's just my opinion though, it's quite possible there are other factors I'm not seeing here.

Of course I didn't mean to come here and be difficult so thank y'all for the help!

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tim.m30
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Re: ESD Causing Restarts

Dec 10, 2018 9:40 pm

Several issues around making devices ESD insensitive. I come from the measurement industry - we sold $10k to $350k+ measurement devices. ESD will easily blow the front ends of said devices; and a sufficiently large ESD to the case of said devices will reset them. Even in their certified UL metal cases with everything that can be earthed earthed. We did very elaborate engineering to minimize the effects, but you can never eliminate them all short of a Faraday cage. Think mini-nuke next to a device. The spark is more or less harmless, but the magnetic field the spark creates passes right through most metals.

ESD is nasty stuff -- and you can easily blast your TV set with ESD and damage it. You've just been lucky.

ESD control is the solution. Most people have carpet that has carbon threads that help control ES buildup. Surprised your carpet doesn't. I think there are sprays you can buy that apply a conductive material to help reduce ES charges... but probably not as reliable as a typical carpet you can buy these days.

Another choice is a anti-static mat you put on the floor in front of the printer... but it will still take a few seconds to deplete a healthy charge if you are trying to make sparks.

michael.b133
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Re: ESD Causing Restarts

Dec 11, 2018 12:35 am

Regarding measurement devices, I'm not surprised that ESD would blow up the input to them, a fair number of our large high bandwidth scopes have ESD warnings plastered on the front. As I understand, high end measurement equipment has other requirements that can limit the ESD protection used (a high bandwidth scope, for example, might not be able to use TVS diodes due to their parasitic capacitance).

In general though, you're right that a suffcienctly large ESD event will cause damage to just about anything. On the other hand, your typical consumer doesn't want to wear a wrist strap when they use their laptop, so manufacturers go through ESD testing to make sure typical events won't damage their products. In my line of work we don't do any system level design or testing, but I believe the standard for a system level ESD test is IEC 61000-4-2. It's probably a safe assumption that testing like that is only done on consumer products, but I really can't say for sure.

The carpet is an interesting note. I've never actually seen ESD carpet in a home (and I couldn't actually find any household carpet with static-dissipative properties online, most were 100% polyester), I've only really ever seen static dissipative hard flooring, we use it in our test floor at work. It might be a regional thing.

I have a suspicision that the Einsy and indeed most of the printer is fine with the ESD that caused restarts and my issue was the power panic board was especially sensitive and triggering a mains fault. At the end of the day, grounding the frame seemed to get rid of my issue, so I'll probably leave it at that. I'd recommend it as a precaution in general, as we said it won't be perfect, but at least it seems to help some.

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tim.m30
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Re: ESD Causing Restarts

Dec 11, 2018 8:04 am

Well, good luck. Hope the paint and plastic doesn't keep any of the many parts from being too well isolated. The ribbon cables are great antenna, and I suspect the I/O devices are not well protected (based on the part's ESD warning). Then there's the thermistor bridge inputs... things are allowed to rattle around 60 volts or so between the board and chassis ground - which doesn't appear to be used anywhere but the PS chassis.

As for any IEC or JEDEC testing? Good luck on that, too. The printer has a CE mark only because the frame is all considered low voltage and doesn't require electrical safety testing to CE standards. Even the power supply is unmarked (as far as I can tell without dismantling). Caveat Emptor, as they say.

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randolph.l
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Re: ESD Causing Restarts

Dec 11, 2018 5:25 pm

OnMy Rostock Max delta printer I had to run the ribbon cable through and around a ferrite doughnut to isolate the lcd display from noise from other electronics.

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