I take them outside and use the 90PSI industrial strength air compressor on them. That gets the dust out, those little cans and vacuum cleaners are a waste of time and money. This is a job for horsepower. ;-) Just don't let the fans spin and everything will be okay.
By the way. It might sound like a troll but it's not. I did a quick search of the archives and didn't find the answer to this common question. A retired engineer told me that the air flowing through the plastic leaf blower tube can produce static electricity, that's one reason I ask.
Maybe set up an experiment that measures the amount of static electricity produced in a computer chassis from the air from a leaf blower?
My physics is a bit crappy... I'm not clear on how rushing air (which is mostly nitrogen) on a PCB mounted on an earth grounded chassis can create damaging charge differences. Electron stealing happening?
I don't recall getting zapped when I blast sawdust off my clothes with an air gun..
But I do know that static electricity from a helicopter can be lethal....
A PC with a lot of installed components doesn't have sensitive points; the wires that go to sensitive MOS inputs are all connected to OUTPUT circuits that act as voltage limiters (clamps). After you unplug something from your PC, the fingers of that board (or pins of that CPU) are potentially at risk.
Yes, modern designs are much less at risk than those of the
1980s, and while everyone claims antistatic precautions are 'very important', there aren't lots of failures from that source to back them up. 2000V stress tests are part of lots of modern designs, but the handling 'precautions' still are based on the experiences of a quarter century ago.
I've seen plastic washers and carbon resistors in antistatic bags with warning stickers. Those components have NO static sensitivity, short of taking lightning strike damage...
The canned-air units might develop some static charge on the tube, BUT that tube is tiny (the 2000V test is for a full sized human at voltage) and the charge is likely never to leave the insulator surface. Your PC will never know it's there.
Its more likely that a static charge will be built up inside the leaf blower (or whatever) based on its component materials and contaminants (dust, moisture) in the air.
Once that comes in contact with components in proximity to a grounded chassis, this charge can be transferred to adjacent (ungrounded) components. At some point, this will build up to a voltage w.r.t. ground that exceeds component ratings.
Canned air, being relatively clean and dry is less able to generate and transport such a charge.
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10 yrs ago I worked in the mfg plant area of a SMPS OEM as a product and test engineer. There were some compressed air lines with hoses about here and there for some reason (I think that section of plant had been used for other things in the past). We weren't using the hoses but the same hard line they came from was used for the air powered screwdrivers. I remember the nozzle on the ends of them had a fitting with radiation warning stickers on it. I asked someone about it once and apparently there was some sort of low level source in there emitting radiation intended to bleed off any static charges that would build up. I've never researched this since so I could off on the explanation I was given.
The OP has been told the truth...but as the commercial says: It Isn't the Heat, It's the Humidity. The magnitude of the electrical charge that can build up due to moving air (which, like the moving belt in a Van de Graf generator, is not a conductor) depends mostly on the ambient relative humidity. WRT leaf blowers: Here in Albuquerque, I've twice started fires with my B&D Electric Leaf Blower with a thick, loud-enough-to-be-heard-over-the-blower, visible in bright sunlight, blue spark from the end of the nozzle to the pile of lawn debris. Also here, I get very visible sparks from the red-plastic tube of a can of "Dust Off" to ground when the humidity is as low as it often is (0 to 10 percent). Same with vacuum cleaners. So: I don't use anything involving moving air (or carbon dioxide: Dust-Off) on electronics until monsoon season. You might consider checking the relative humidty (or measuring it...which is much better) before "cleaning".
OR: Get a Polonium 210 source to attach to the end of your vacuum cleaner nozzle (a violation of Federal Law if you do this yourself...by disassembling an ionization-type smoke detector, for example). Might also cause you to be cavity-searched the next timeyou fly commercial.
I wonder if an earth grounded mesh put in front of the leaf blower nozzle would reduce the amount of charged air. Maybe then it could to be safe to blow an earth grounded computer chassis? (I'll admit I think its a nutty idea to use a leaf blower..but it's entertaining. ) Did the OP mention if the leaf blower was gas powered? :) D from BC
Yes moving air can create charges that product static electricity. But as whit3rd noted:
A system resilient to thousands of volts per IEC1000-4-2 would use devices such as:
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Swtiches are also rated for 20,000 volts. However all these claims come with an assumption. Once those parts are no longer part of a 'system', then its protection does not exist or is easily compromised. All these protetion solutions - even a plastic switch - assume that static electricity has an alternative (shunt) path that does not pass through electronics.
Same 'system' that makes static electric discharges irrelevant must also make static electric discharges not cause a computer crash. How to find a 'system' design error? Leather slippers and a nylon rug on a cold winter day make an excellent testing tool when 'system' is on a glass table top. Yes, glass because so many other table tops are acutally too conductive at those testing voltages.
Static discharge to every part of a system's externals must not cause any software interruption. This is the same protection system that also makes electronics so resistant to larger and hardware destructive transients.
A plastic switch that is not mounted conductive to its chassis therefore no longer provides 20,000 volt protection. Just one example of why all 'systems' should be fully static electric resilent AND why disconnecting anythnig from a 'system' can make that part suspectible to static electric damage or overstress.
Yes, but it's the particles in the air that develop a charge, not the air itself. The main determinant of how much voltage is the humidity. A dry day with lots of particles (dust, pollen, even dry snow) in the air can be a real shocker!
Niels Jonassen wrote an excellent series of articles on static and ESD a while ago. You can find them here
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Personally I just wash down a PC with the old HP "secret cleaner" formula (80% water, 20% IPA with a few drops of washing-up liquid), then blast it with shop air at 80-90 psi. Don't hit the fans with that air though, they can spin up pretty fast! Then let it dry out in the sun for a while, or 30 mins in an oven if it's crap weather.
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Most definitely NOT. In fact, given the increasingly smaller process sizes, I would say that many chips are actually MORE sensitive to ESD than from a few years back.
Understandable. There's a lot of myths and misinformation about it.
Just generic plastic. However, there's not enough there to jump an air gap.
Actually, my understanding is that there's less danger from ESD, to the computer's innards, than there is from tiny bits of debris or drops of oil, or other contaminants, that may be present in the air stream from the compressor. There is also the risk, with excessive air pressure (some have been known to use 50-100 PSI) of literally blowing smaller components right off the board involved.
My first recommendation, for any type of cleaning such as you describe, is that you use a good-quality ESD-safe service vacuum. 3M makes a very nice one that, although pricey (in the mid-200's), is durable as blazes and is actually rated to suck up toner with the right filter.
I know, from direct experience, that vacuuming a board or component in this manner removes far more dust and gunk than blasting it with air.
If you must use compressed air to clean, make sure that your line has top-rate filtration for both dust and fluids, and don't use more than about 30 PSI.
Happy cleaning.
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I really appreciate all discussion, very informative as always. A leaf blower won't thoroughly clean, but it doesn't present a clear hazard unless the air is dirty. I thought (wrong) it was an obvious electrostatic hazard. Thanks.
I've never worried a lot about the dirt in a computer. I do worry a lot about ESD. Whenever I have my computer case open, though, I do use one of those pressured air-cans to clean it up a little bit and I always wear an ESD wrist-strap. I concentrate mostly on the fans and heat sinks.
When I give away an old computer to family or friends, I try to replace all the fans, including the CPU fan.
I did have a CD/DVD burner go out a while back and I know that I haven't used it all that much. I do wonder if it might have something to do with the dander my dog produces when she's shedding.
I monitor internal temperatures once in awhile with software.
Actually, this is about the stupidest question I've ever heard of. If you would seriously consider blowing the dust out of your computer with a leaf blower, then you probably shouldn't be allowed to operate either.
*AHEM* ... the important characteristic is particle size. A little bit of energy is required to put charge on a particle. For a single atom or gas molecule, this is the 'ionization energy' and is typically a volt or so, but that means the electric field has to be one volt per atomic-diameter (very unlikely). Charging a leafy bit, you only need one volt per leafy-bit-diameter (likely), so you get lots of moving charge in a blower full of sawdust, leafy bits, maybe even dust.
The ease of ionization of large molecules and particles is the principle behind electrostatic scrubbers and household smoke detectors. Oil spray in a compressed air system will be a problem, but the air itself is not.
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