Static is [not] your friend - vacuuming PC?

A static charge from the vacuum cleaner can STILL jump to the exposed
computer circuitry, even with the computer turned off. The computer being
grounded makes no difference. Don't do it. Use a can of compressed air to
BLOW the dust outlike everyone in the business does.

--
DaveW



"Sammo" wrote in message
...
In terms of static, how safe is it to clean inside a home PC by using
a vacuum cleaner?

Some people like this website suggest that it is unwise.
http://www.dansdata.com/sbs3.htm

If my PC is switched off but remains earthed (to the mains earth) and
I am careful not to do physical damage to the PC with my home vacuum
cleaner, then surely there is no problem with static?

Am I overlooking something?

Sammo

--

DaveW wrote:

A static charge from the vacuum cleaner can STILL jump to the exposed
computer circuitry, even with the computer turned off. The computer being
grounded makes no difference. Don't do it. Use a can of compressed air
to BLOW the dust outlike everyone in the business does.


lots of vacuum cleaners have a metal tube the attachments
go to, just ground the tube to the same ground as the
PC. Then what you're worried about above won't happen.

You folks should stop obsessing about the damn dust in your machine. If you are
really that concerned, take it in the bathroom, turn on the shower and steam
the place up, then dust it out.
Personally I don't think a little dust is going to hurt anything. If it ain't
broke don't fix it!

"DaveW" wrote:
A static charge from the vacuum cleaner can STILL jump to the exposed
computer circuitry, even with the computer turned off. The computer being
grounded makes no difference. Don't do it. Use a can of compressed air to
BLOW the dust outlike everyone in the business does.

The compressed air is just about as bad as the vacuum cleaner...
maybe even worse in some ways.

--
FloydL. Davidson http://web.newsguy.com/floyd_davidson
Ukpeagvik (Barrow, Alaska)

Gumby wrote:
DaveW wrote:

A static charge from the vacuum cleaner can STILL jump to the exposed
computer circuitry, even with the computer turned off. The computer being
grounded makes no difference. Don't do it. Use a can of compressed air
to BLOW the dust outlike everyone in the business does.


lots of vacuum cleaners have a metal tube the attachments
go to, just ground the tube to the same ground as the
PC. Then what you're worried about above won't happen.

Static charge on the nozzle is not the only problem. The buildup
of static on the various components as a result of blowing dry air
on them is just as serious as the nozzle (same source of charge!).

--
FloydL. Davidson http://web.newsguy.com/floyd_davidson
Ukpeagvik (Barrow, Alaska)

In comp.sys.ibm.pc.hardware.chips Dave Platt wrote:
For what it's worth... Bob Pease, a respected designer at
National Semiconductor and author of a number of very useful
books including "Troubleshooting Analog Circuits", swears by
the use of a dishwasher for cleaning PC boards especially
for high-impedance, low-leakage circuits. He mentioned
the use of a "standard load of Calgonite" as the cleaning
agent... run 'em though the wash cycle, take out after the
rinse, shake off excess water, and allow to air-dry.

Pease comments that after this sort of treatment, leakage
currents across the board surface were often lower than
could be achieved using an expensive commercial solvent-based
PC-board-washing system.

Useful data! I have little doubt that a diskwasher can
get boards extremely clean.

For what it's worth, the Calgonite MSDS lists sodium
tripolyphosphate, sodium silicate, sodium carbonate, and
sodium sulphate. No hypochlorites.

Ah, that helps a bit. Hypochlorite is nasty on copper (verdegris)
and other metals. The other goodies will make for high pH,
but that usually won't do more than frost over aluminum and zinc.

-- Robert

For example, gold-plated glassware/chinaware should NOT be put to
dishwasher. I wonder if it's because of the detergent.

"Robert Redelmeier" wrote in message
...
In comp.sys.ibm.pc.hardware.chips kony wrote:
What do you consider "nasty" about Dishwasher Detergent?

Machine detergent. The pH is around 12 and there's chlorine.
This will cause corrosion of copper and perhaps solder.

I have cleaned a LOT of boards in a tub of warm water and
detergent (dishwasher or whatever was handy) with a

Hand dishwashing detergent is much less corrosive
than the automatic machine variety.

-- Robert

Robert Redelmeier wrote in message . com...

Anybody have any good experiences cleaning IBM Model
"M" keyboards in a (soapless) dishwasher?

The key matrix is made of 2 separate flexible circuit boards attached
together around the edges, similar to matrixes found in NMB keyboards,
including the Microsoft Natural, and moisture can remain trapped
between them. Normally you can remove those flexible boards and dry
them out enough with 90%+ alcohol, but IBM put them between a hard
piece of plastic and a sheet of metal "riveted" to together (ends of
plastic rods melted against the metal), which traps the moisture even
better. So you may have to cut off the rivet heads to get to dry out
the key matrix and then replace the rivets with install washers and
tiny screws.

Robert Redelmeier wrote:
Dave Platt wrote:

.... snip ...

For what it's worth, the Calgonite MSDS lists sodium
tripolyphosphate, sodium silicate, sodium carbonate, and
sodium sulphate. No hypochlorites.

Ah, that helps a bit. Hypochlorite is nasty on copper (verdegris)
and other metals. The other goodies will make for high pH,
but that usually won't do more than frost over aluminum and zinc.

Isn't hypochlorite just plain fixer from the darkroom? Which
required several hours of washing of prints.

--
Chuck F ) )
Available for consulting/temporary embedded and systems.
http://cbfalconer.home.att.net USE worldnet address!

"Floyd L. Davidson" wrote in message
...
Sammo wrote:
In terms of static, how safe is it to clean inside a home PC by using
a vacuum cleaner?

Some people like this website suggest that it is unwise.
http://www.dansdata.com/sbs3.htm

The web page descriptions are indeed fairly funny, if you know
what they are talking about. But I highly suspect anyone with a
limited background in Electro Static Discharge will be more
confused than not.

If my PC is switched off but remains earthed (to the mains earth) and
I am careful not to do physical damage to the PC with my home vacuum
cleaner, then surely there is no problem with static?

Am I overlooking something?

Yep. Quite a lot.

*Moving* *dry* *air* around is a great way to build up a static
charge on any component that is an insulator.

Hence *compressed* *dry* *air* and *vacuum* *cleaners* are not
good ideas. In fact, compressed air might be worse because it
can forcefully blast dust into places it wouldn't otherwise go.

If you get enough charge (a few thousand volts, for example, is
common), it will then break down the insulation between the
charge and the next nearest object that is either also holding a
charge or is able to dissipate the charge (e.g., a conductor).
The current flow when that happens is what kills your computer.
And it isn't just that specific current, but also any current
induced into other conductors as a result of that current.

The way to get the dust out of a computer case safely is to use
a damp rag to manually pick up dust. It shouldn't be so wet
that it drips moisture (though that isn't necessarily bad
either, see below), but needs to be damp enough that dust will
stick to it and static cannot build up on it. I personally
prefer to have a large bowl of water mixed with a little
household cleaner (such as 409 or Mr. Clean), in which the dust
rag (a well worn bathroom wash cloth or a thin dish towel, is
nice) is washed as it get dirty. The soapy water in the bowl
should be changed somewhat regularly too, i.e. when it gets so
dirty that as much dirt moves from the water to the rag as from
the rag to the water!

Which type of soap to use does make a difference. The idea is
something that will dissolve any grease film or other coating
that might be present, but even more important is that it be a
good water dispersant. Automatic dishwater soap is perhaps the
best in that respect.

Note that there aren't many things which can actually be damaged
by water itself. Disk drives or CRDOM/DVD drives (things with
moving parts) can be damage by water. But keyboards and
motherboards can be totally immersed in water without damage.
Any time that a system is *really* dirty, or is taken apart for
other reasons, it makes sense to literally wash the device in a
kitchen sink with a solution of soapy water, and then rinse it
off with a water spray if you have one of those handy spray
hoses meant for cleaning dishes.

You've gone just plain NUTS. I have to replace a few keyboards every
month because some bozo spilled a bottle of Dasani water in it. Coffee
is even worse. The little rubber dimples in the rubber pad collect the
water, and they will *never* dry out unless you pull the keyboard apart
and let it dry. And the cost of labor is greater than the ten dollars a
new keyboard costs. And if you pull one apart, you may never be able to
get it back together. Don't believe me? Try it sometime with a defunct
keyboard! The really funny part of all this is the deviant behavior the
user will display when you ask him or her if they spilled something in
the keyboard. "Who, me? Never!" and I pick the keyboard up and the
wter drips out of it. Yeah, right. :-(

Floyd doesn't tell you but he lives in an igloo in a god-forsaken part
of Northern Alaska where the ground is frozen all year long. His harsh
cleaning methods aren't recommended and are a lot of hooey, IMHO,
because the rag will damage the pins of the chips in a circuit board.
It's insane to use anything but compressed air.

If the water supply is very hard (filled with minerals) and will
leave a residue, use a final bath of rubbing alcohol. Otherwise
a very dilute solution of automatic dishwater soap is probably best.
(It will leave a very thin film of water dispersant, loaded with
water, on everything. That will help protect against static and
it will also reduce dust build up because of reduced static build
up.)

After such a dunking it takes considerable time to be sure that
the water has dried completely. In places where the humidity is
low that will happen in a day or two anyway, so just put it on
the shelf and wait. Otherwise one method is to use a kitchen
oven on warm, leave the door partially open and put the device
inside the oven for several hours.

Nuts! Totally nuts! That's an excellent way to ruin it! You'll bake
the circuit board!

But *don't* use compressed air, vacuum cleaners, plastic brushes,
or synthetic cloth to clean a computer. And don't do it on a
day when the relative humidity is 10% either.

Which is ALL the time where you live! You've gotta be _kidding_ with
this post!

--
FloydL. Davidson http://web.newsguy.com/floyd_davidson
Ukpeagvik (Barrow, Alaska)