Static is [not] your friend - vacuuming PC?

[Sammo]

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

--

[=?UTF-8?B?UGFsaW5kcuKYu21l?=]

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 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?


Electrostatic discharge can produce some intersting effects
on semiconductors and the risk shouldn't be discounted.

However I have cleaned out the interior of countless cases
with no apparent ill effect- using a soft haired paintbrush
in one hand whilst hovering over the area with the nozzle of
a domestic vacuum cleaner in the other. Due to the nature of
the job, one hand or both is in contact with the case most
of the time and so there is little chance for static build
up on the nozzle/your body/brush. Touching the case before
introducing the brush is a good idea.

Personally, I prefer to have the case sat on an esd mat to
leaving it plugged in - not so much from the static point of
view but a marked reluctance to work on anything with power
on or connected, unless unavoidable (like, I don't have the
mat with me).

Not to be done to a laser printer, but for other reasons.

--

Sue

[Cuzman]

"Sammo" <noone@no-where.com> wrote in message
news:958F7E6A631A81A7D4@204.153.244.156...

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


IMO it's still not safe at all. Buy a can of compressed-air from an
electrical hardware store.

[Watson A.Name - \Watt Sun, the Dark Remover\]

"Sammo" <noone@no-where.com> wrote in message
news:958F7E6A631A81A7D4@204.153.244.156... 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?

Static can be caused by the brush bristles. Use compressed air instead.
Sammo --

[Jerry G.]

Using a vacuum cleaner in a PC, or any electronics devices using CMOS
technology is not safe at all. It does not matter how well everything is
grounded. The fact of having a motion contact using device that uses an
insulating material can cause a static build-up. You can read up on static
electricity generation for details.

Even handling the circuit boards under some conditions are at risk for
damage from static electricity. Most of the appliances of today, such as
TV's, radios, VCR's, DVD's, and many other types of devices are using CMOS
devices. Great care should be taken when handling these devices. I have seen
units damaged from improper handling.

The proper way to clean any electronics equipment is to use filtered
compressed air. The unit and the operator of the compressed air must be in
contact to each other in reference to the unit's ground plain (metal case
for example), to prevent any potential difference between them.

The compressed air blown from a distance of at least 6 to 10 inches will
give no effect to build up static charges, and cause any problems with the
device being cleaned.

--

Jerry G.
==========================


"Sammo" <noone@no-where.com> wrote in message
news:958F7E6A631A81A7D4@204.153.244.156...
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

--

[Noozer]

"Sammo" <noone@no-where.com> wrote in message
news:958F7E6A631A81A7D4@204.153.244.156... In terms of static, how safe is it to clean inside a home PC by using a vacuum cleaner?

DON'T DO IT
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?

By leaving the PC grounded you are giving static a perfect path from the
vacuum, through your parts, to ground... GREATLY increasing the risk of
damage.

Use compressed air!

[Floyd L. Davidson]

Sammo <noone@no-where.com> wrote:In terms of static, how safe is it to clean inside a home PC by usinga 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) andI am careful not to do physical damage to the PC with my home vacuumcleaner, 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.

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.

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.

--
FloydL. Davidson <http://web.newsguy.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska) floyd@barrow.com

[Robert Redelmeier]

In comp.sys.ibm.pc.hardware.chips Floyd L. Davidson <floyd@barrow.com> wrote: good water dispersant. Automatic dishwater soap is perhaps the best in that respect.

Aaaakkk! No! Dishwasher machine soap (Cascade) is one of
the nastiest cleaners I know. Full of trisodium phosphate,
silicates and calcium hypochlorite. Perhaps you mean
dishwasher anti-spot filming agent (JetDry). This stuff
should be very benign when diluted.

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

Well, I guess in AK you have to worry about the latter :)

I'm less worried about compressed air than I am about vaccuum
because compressed air nozzles are easier to ground and less
likely to contact parts. Static can build up from moving gas
past parts, but the parts should drain that small amount away.
It's bigger (perhaps still invisible) discharges that cause
trouble.

-- Robert

[Floyd L. Davidson]

Robert Redelmeier <redelm@ev1.net.invalid> wrote:In comp.sys.ibm.pc.hardware.chips Floyd L. Davidson <floyd@barrow.com> wrote: good water dispersant. Automatic dishwater soap is perhaps the best in that respect.Aaaakkk! No! Dishwasher machine soap (Cascade) is one ofthe nastiest cleaners I know. Full of trisodium phosphate,silicates and calcium hypochlorite. Perhaps you meandishwasher anti-spot filming agent (JetDry). This stuffshould be very benign when diluted.

Yep, that's a bad one. Another good wetting agent is Photo Flo,
sold by the gallon for darkroom use (or in smaller quantities at
exorbitant prices).
Anybody have any good experiences cleaning IBM Model"M" keyboards in a (soapless) dishwasher? 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.Well, I guess in AK you have to worry about the latter :)

Depends on where. E.g., humidity in Arizona, New Mexico, and
west Texas is low. It is in the Alaskan interior too.

The current relative humidity here is 70%, and that is typical.
I'm less worried about compressed air than I am about vaccuumbecause compressed air nozzles are easier to ground and lesslikely to contact parts. Static can build up from moving gaspast parts, but the parts should drain that small amount away.It's bigger (perhaps still invisible) discharges that causetrouble.

"Moving gas" is probably one of the *worst* offenders (next to
cats and walking on carpets), and is exactly what is wrong with
using a vacuum cleaner. There is no difference between that
and compressed air, as far as static goes. Grounding the nozzle
is not useful, other than to prevent a direct discharge from
buildup on the nozzle itself. And it is *not* reasonable to
expect either small or large charges to drain harmlessly away
from components.

The whole concept of using moving air is a disaster plan!

Of course, if the relative humidity is 50% or above... the
chances are fair that no damage will be done. If it is more
like 6%, either use full protection or you *will* get bit. (I
lived in Fairbanks for a couple decades, where at -40F in the
winter you can almost be assured that the relative humidity
inside any building that does not have a humidifier will be well
below 10%. You don't need a carpet! Just the wrong shoes or
shirt will be enough...)

--
FloydL. Davidson <http://web.newsguy.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska) floyd@barrow.com

[CBFalconer]

"Watson A.Name - \"Watt Sun, the Dark Remover\"" wrote: "Sammo" <noone@no-where.com> 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? Static can be caused by the brush bristles. Use compressed air instead.

<facetious>
Avoid all static problems by using a grounded wire brush <g>.
</facetious>

--
Chuck F (cbfalconer@yahoo.com) (cbfalconer@worldnet.att.net)
Available for consulting/temporary embedded and systems.
<http://cbfalconer.home.att.net> USE worldnet address!

[John]

On Wed, 27 Oct 2004 13:55:09 GMT, "Noozer"
<dont.spam@me.here> wrote:
"Sammo" <noone@no-where.com> wrote in messagenews:958F7E6A631A81A7D4@204.153.244.156... In terms of static, how safe is it to clean inside a home PC by using a vacuum cleaner?DON'T DO IT 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?By leaving the PC grounded you are giving static a perfect path from thevacuum, through your parts, to ground... GREATLY increasing the risk ofdamage.Use compressed air!

EXACTLY, though I usually get away with using a dry paint
brush when compressed air isn't handy. There is slight
potential for static but I've never had any damage result.

[John]

On Wed, 27 Oct 2004 15:13:14 GMT, Robert Redelmeier
<redelm@ev1.net.invalid> wrote:
In comp.sys.ibm.pc.hardware.chips Floyd L. Davidson <floyd@barrow.com> wrote: good water dispersant. Automatic dishwater soap is perhaps the best in that respect.Aaaakkk! No! Dishwasher machine soap (Cascade) is one ofthe nastiest cleaners I know. Full of trisodium phosphate,silicates and calcium hypochlorite. Perhaps you meandishwasher anti-spot filming agent (JetDry). This stuffshould be very benign when diluted.Anybody have any good experiences cleaning IBM Model"M" keyboards in a (soapless) dishwasher?


What do you consider "nasty" about Dishwasher Detergent?

I mean, what harm do you expect?

I have cleaned a LOT of boards in a tub of warm water and
detergent (dishwasher or whatever was handy) with a
paintbrush, it does a great job and the boards worked fine
afterwards, still do. Two important things to do though,
are removing the battery and EPROM first. Of course it's
also necessary to _completely_ dry the boards, including
water wicked under chips and in sockets, which can take a
few days or gentle heating.

[Robert Redelmeier]

In comp.sys.ibm.pc.hardware.chips kony <spam@spam.com> 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

[Tzortzakakis Dimitrios]

Yeah-there's no real reason you need to vacuum your PC.Long before you have
damage from dust, you will be upgrading to a new PC (say 5 years, which is a
moderate life span for an ordinary PC0luck or unluck this can be up to 7
years).Before dust will reach dangerous levels, critical components should
fail first.It's not a good idea to open your PC just for cleaning, though.My
vendor told me these things.

--
Dimitris Tzortzakakis,Iraklion Crete,Greece
major in electrical engineering-freelance electrician
FH von Iraklion-Kreta, freiberuflicher Elektriker
dimtzort AT otenet DOT gr
Ï "Sammo" <noone@no-where.com> Ýãñáøå óôï ìÞíõìá
news:958F7E6A631A81A7D4@204.153.244.156... 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 --

[Dave Platt]

In article <a8uvn0p9hqd6524sjlhv3urimnd4iofg8e@4ax.com>,
kony <spam@spam.com> wrote:
Aaaakkk! No! Dishwasher machine soap (Cascade) is one ofthe nastiest cleaners I know. Full of trisodium phosphate,silicates and calcium hypochlorite. Perhaps you meandishwasher anti-spot filming agent (JetDry). This stuffshould be very benign when diluted.Anybody have any good experiences cleaning IBM Model"M" keyboards in a (soapless) dishwasher?What do you consider "nasty" about Dishwasher Detergent?I mean, what harm do you expect?

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.

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

In my area (Mountain View, Silicon Valley, fairly hard water) I'd
probably do a final rinse by hand using distilled or deionized water,
to prevent mineral deposits from developing ("hard water" spots). An
anti-spot sheeting/filming agent might eliminate this risk, or might
not... haven't tried it.

--
Dave Platt <dplatt@radagast.org> AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

[John]

On Wed, 27 Oct 2004 19:55:34 GMT, Robert Redelmeier
<redelm@ev1.net.invalid> wrote:
In comp.sys.ibm.pc.hardware.chips kony <spam@spam.com> 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.

Not significant for short-term exposure, in a dilluted bath.
There should be minimum if any copper exposed on a board to
begin with.

I have cleaned a LOT of boards in a tub of warm water and detergent (dishwasher or whatever was handy) with aHand dishwashing detergent is much less corrosivethan the automatic machine variety.


Perhaps but it also isn't as good at cleaning. Boards
washed in dishwasher detergent came out looking BETTER than
brand new, even new boards have some residue/flux/etc that
the detergent removes. I don't recommend leaving a board to
soak in it though, generally I submerge them and they're
done within a few minutes or less.

[John]

On Wed, 27 Oct 2004 22:56:50 +0300, "Tzortzakakis Dimitrios"
<dimtzortihatespam@nospamotenet.gr> wrote:
Yeah-there's no real reason you need to vacuum your PC.Long before you havedamage from dust, you will be upgrading to a new PC (say 5 years, which is amoderate life span for an ordinary PC0luck or unluck this can be up to 7years).Before dust will reach dangerous levels, critical components shouldfail first.It's not a good idea to open your PC just for cleaning, though.Myvendor told me these things.

It depends a lot on the environment. Too often we assume
queries are only related to home PCs but these days almost
any business has some too.

Your vendor likely told you not to open it to minimize risk
of user-induced problems within the warranty period. They
expect a system to keep running for that period and don't
care as much about longer-term effects. It is a good idea
to open and clean a PC at whatever interval is dictated by
the environment. Often "cleaning" doesn't mean getting
every little spec of dust out, simply checking the primary
fans and heatsink(s) for buildup.

[Floyd L. Davidson]

kony <spam@spam.com> wrote:Use compressed air!EXACTLY, though I usually get away with using a dry paintbrush when compressed air isn't handy. There is slightpotential for static but I've never had any damage result.

You might as well use a vacuum cleaner. It isn't any worse,
and it is a whole lot easier.

Actually, a "dry paint brush" might be the *worst* thing I've
heard of yet!

*Any* *dry* *insulator* is bad news. Two pieces of paper rubbed
together are bad. One of the worst offenders is putting tape of
any kind onto a static sensitive circuit board, and then removing
it. The potential generated when a one inch strip of tape is
peeled away is just horrendous.

Here's a chart that I found at

http://www.esdsystems.com/training/staticgeneration.htm

They say the data comes from "AT&T ESD Control Handbook-1989".

TYPICAL ELECTROSTATIC VOLTAGES

EVENT RELATIVE HUMIDITY
10% 40% 55%

Walking across carpet 35,000 15,000 7,500
Walking across vinyl floor 12,000 5,000 3,000
Motions of bench worker 6,000 800 400
Remove DIPs from plastic tubes 2,000 700 400
Remove DIPs from vinyl trays 11,500 4,000 2,000
Remove DIPs from Styrofoam 14,500 5,000 3,500
Remove bubble pack from PCBs 26,000 20,000 7,000
Pack PCBs in foam-lined box 21,000 11,000 5,500

The immediate point that comes to mind is how much difference
relative humidity makes, and how something you've commonly been
doing at 70% relative humidity might just blow away everything
if you do it on a day when the humidity is only 10-20%. Look at
"Motions of bench worker"!

--
FloydL. Davidson <http://web.newsguy.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska) floyd@barrow.com

[Roger Hamlett]

"CBFalconer" <cbfalconer@yahoo.com> wrote in message
news:417FCD85.B6A912E2@yahoo.com... "Watson A.Name - \"Watt Sun, the Dark Remover\"" wrote: "Sammo" <noone@no-where.com> 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? Static can be caused by the brush bristles. Use compressed air instead. <facetious> Avoid all static problems by using a grounded wire brush <g>. </facetious>
Funnily enough, this is the correct answer!...
You can get brushes, with conductive bristles, and a grounding 'tag', that
attaches to the standard fittings used on electronic benches, for exactly
this purpose. On a workbench, with a grounded surface, and filtered
extraction, it allows you to 'de-dust' CMOS components before servicing,
and is standard equipment on a lot of service benches.

Best Wishes

[John]

On Wed, 27 Oct 2004 12:21:06 -0800, floyd@barrow.com (Floyd
L. Davidson) wrote:
kony <spam@spam.com> wrote:Use compressed air!EXACTLY, though I usually get away with using a dry paintbrush when compressed air isn't handy. There is slightpotential for static but I've never had any damage result.You might as well use a vacuum cleaner. It isn't any worse,and it is a whole lot easier.Actually, a "dry paint brush" might be the *worst* thing I'veheard of yet!

It may seem that way to you but I've noticed static buildup
from vaccume but not from the brush.

*Any* *dry* *insulator* is bad news. Two pieces of paper rubbedtogether are bad. One of the worst offenders is putting tape ofany kind onto a static sensitive circuit board, and then removingit. The potential generated when a one inch strip of tape ispeeled away is just horrendous.Here's a chart that I found at http://www.esdsystems.com/training/staticgeneration.htmThey say the data comes from "AT&T ESD Control Handbook-1989". TYPICAL ELECTROSTATIC VOLTAGES EVENT RELATIVE HUMIDITY 10% 40% 55% Walking across carpet 35,000 15,000 7,500 Walking across vinyl floor 12,000 5,000 3,000 Motions of bench worker 6,000 800 400 Remove DIPs from plastic tubes 2,000 700 400 Remove DIPs from vinyl trays 11,500 4,000 2,000 Remove DIPs from Styrofoam 14,500 5,000 3,500 Remove bubble pack from PCBs 26,000 20,000 7,000 Pack PCBs in foam-lined box 21,000 11,000 5,500The immediate point that comes to mind is how much differencerelative humidity makes, and how something you've commonly beendoing at 70% relative humidity might just blow away everythingif you do it on a day when the humidity is only 10-20%. Look at"Motions of bench worker"!

Let's put that in context though...
You have a DIP in a tray, or a PCB in a foam-lined box...
are you supposed to just leave it in the box because
removing it would generate static??? Of course not.

If you don't want to use a paintbrush, fine, but I've been
doing so for years and NEVER had a problem. I am not
recommending anything in particular though, there is no
cleaning method that is foolproof but one suggestion you
made to use a damp rag is about the worst thing imaginable,
because it will leave a gross-looking mess everywhere, as if
the board were left out in an alley during a thunderstorm
and debris washed up all over it. If there is enough dust
that it really needs cleaned, a damp rag is just going to
make a huge mess... been there, done that, found a better
way.

[DaveW]

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" <noone@no-where.com> wrote in message
news:958F7E6A631A81A7D4@204.153.244.156... 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 --

[Gumby]

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.

[Greg]

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!

[Floyd L. Davidson]

"DaveW" <none@zero.org> wrote:A static charge from the vacuum cleaner can STILL jump to the exposedcomputer circuitry, even with the computer turned off. The computer beinggrounded makes no difference. Don't do it. Use a can of compressed air toBLOW 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) floyd@barrow.com

[Floyd L. Davidson]

Gumby <none@xxxyy.com> 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 attachmentsgo to, just ground the tube to the same ground as thePC. 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) floyd@barrow.com

[Robert Redelmeier]

In comp.sys.ibm.pc.hardware.chips Dave Platt <dplatt@radagast.org> 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

[Alexander Grigoriev]

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

"Robert Redelmeier" <redelm@ev1.net.invalid> wrote in message
news:W2Tfd.1750$fC4.877@newssvr11.news.prodigy.com... In comp.sys.ibm.pc.hardware.chips kony <spam@spam.com> 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

[do_not_spam_me]

Robert Redelmeier <redelm@ev1.net.invalid> wrote in message news:<eWOfd.12450$Al3.4350@newssvr30.news.prodigy.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.

[CBFalconer]

Robert Redelmeier wrote: Dave Platt <dplatt@radagast.org> 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 (cbfalconer@yahoo.com) (cbfalconer@worldnet.att.net)
Available for consulting/temporary embedded and systems.
<http://cbfalconer.home.att.net> USE worldnet address!

[Watson A.Name - \Watt Sun, the Dark Remover\]

"Floyd L. Davidson" <floyd@barrow.com> wrote in message
news:87lldsnrre.fld@barrow.com... Sammo <noone@no-where.com> wrote:In terms of static, how safe is it to clean inside a home PC by usinga 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) andI am careful not to do physical damage to the PC with my home vacuumcleaner, 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) floyd@barrow.com

[Floyd L. Davidson]

"Watson A.Name - \"Watt Sun, the Dark Remover\"" <NOSPAM@dslextreme.com> wrote:Floyd doesn't tell you but he lives in an igloo in a god-forsaken partof Northern Alaska where the ground is frozen all year long. His harsh

Actually I live in one of the most exciting places in the entire
world. The name of the game is adventure, and there is never a
dull moment.
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.

Your remarks are interesting. Ten/fifteen years ago that was
just about the only kind of response I'd get on Usenet from
claiming one could just soak these things in plain old soapy
water and get good results. But it isn't so common these
days...

Of course I've been putting electronics into a dishwasher for 40
years now too (that right *40* years, which means it was
electron tubes, not ICs). Which makes your protest just
hilarious.

You might have noticed though, that for almost every instance
of someone saying that compressed air is the right way, somebody
else says use water. The fact is that water won't zap your
circuit boards with ESD (and compressed air *will*).

Instead of flapping your jaw about it, you might do a little
research on the subject. See if you can find out what the
significance, for example, of water is for the pink anti-static
material that you commonly see. And why it's pink.
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 bakethe circuit board!

Yer head's where the sun don't shine, son.
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_ withthis post!

That is so ignorant that it is a joke:

Barrow, Wiley Post-Will Rogers Memorial Airport, AK, United States
(PABR) 71-17-07N 156-45-57W 10M
Weather reported at: Thu Oct 28 01:44:00 2004 AKDT
...
Temperature : 12 F (-11 C)
Dew Point : 8 F (-13 C)
*Relative* *Humidity* : *85%*
Pressure (altimeter): 29.63 in. Hg (1003 hPa)

-- http://weather.noaa.gov/weather/current/PABR.html

Do you understand what 85% relative humidity is? It is rather
*normal* in a place that sits on a point jutting out into the
ocean.

--
FloydL. Davidson <http://web.newsguy.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska) floyd@barrow.com

[Jim Douglas]

Give it a blowjob, take it to the garage, get your leaf blower, and blow
away!
"Sammo" <noone@no-where.com> wrote in message
news:958F7E6A631A81A7D4@204.153.244.156... 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 --

[keith]

In article <41808485.FE78EACF@yahoo.com>, cbfalconer@yahoo.com says... Robert Redelmeier wrote: Dave Platt <dplatt@radagast.org> 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.

I thought "fixer" was sodium thiosulfate and some other stuff. Sodium
Hypochlorite is laundry bleach and pool chlorine.

--
Keith

[keith]

In article <87is8vm9tz.fld@barrow.com>, floyd@barrow.com says... "Watson A.Name - \"Watt Sun, the Dark Remover\"" <NOSPAM@dslextreme.com> wrote:Which is ALL the time where you live! You've gotta be _kidding_ withthis post! That is so ignorant that it is a joke: Barrow, Wiley Post-Will Rogers Memorial Airport, AK, United States (PABR) 71-17-07N 156-45-57W 10M Weather reported at: Thu Oct 28 01:44:00 2004 AKDT ... Temperature : 12 F (-11 C) Dew Point : 8 F (-13 C) *Relative* *Humidity* : *85%* Pressure (altimeter): 29.63 in. Hg (1003 hPa) -- http://weather.noaa.gov/weather/current/PABR.html Do you understand what 85% relative humidity is? It is rather *normal* in a place that sits on a point jutting out into the ocean.
What's the RH after you've heated the air to, say, 68F? ;-)

Lesse...

Actual Vapor Density
-------------------- = RH
Saturation Vapor Density

At 14F (close enough) the saturation vapor density is 2.36g/m^3, so
your actual vapor density is: .85 * 2.36g/m^3 or 2.01g/m^3

Raise that air to 68F (saturation density = 17.54g/m^3)


2.01g/m^3
-------- = 11% RH
17.5g/m^3

....seems pretty dry to me. ;-)

--
Keith

[Robert Redelmeier]

In comp.sys.ibm.pc.hardware.chips Floyd L. Davidson <floyd@barrow.com> wrote: "Watson A.Name - \"Watt Sun, the Dark Remover\"" wrote: 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!
That is so ignorant that it is a joke: Barrow, Wiley Post-Will Rogers Memorial Airport, AK, United States (PABR) 71-17-07N 156-45-57W 10M
Weather reported at: Thu Oct 28 01:44:00 2004 AKDT ... Temperature : 12 F (-11 C) Dew Point : 8 F (-13 C) *Relative* *Humidity* : *85%* Pressure (altimeter): 29.63 in. Hg (1003 hPa) Do you understand what 85% relative humidity is? It is rather *normal* in a place that sits on a point jutting out into the ocean.

Floyd, I realize you've been unjustifiably flamed, but that
is no reason to reduce your own credibility by misleading
statements.

Yes, arctic outdoor air usually has high relative humidity.
It has to be, otherwise the snow would sublime.

But that outdoor air is extremely dry in absolute terms.
My psychrometric chart gives 5 grains water per lb dry air for
8'F dewpt. Heated to 60'F, that is 6.4% relative humidity.
You're gonna need big humidifiers and all the fun they are
to maintain (salt build-up, ugh!)

Furthermore, I suspect that static build-up is more a function
of absolute humidity than relative humidity. Do people have
lots of static problems in Phoenix summers?

-- Robert

[Floyd L. Davidson]

Robert Redelmeier <redelm@ev1.net.invalid> wrote:In comp.sys.ibm.pc.hardware.chips Floyd L. Davidson <floyd@barrow.com> wrote: "Watson A.Name - \"Watt Sun, the Dark Remover\"" wrote:> 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!
.... Temperature : 12 F (-11 C) Dew Point : 8 F (-13 C) *Relative* *Humidity* : *85%*
....
Floyd, I realize you've been unjustifiably flamed, but thatis no reason to reduce your own credibility by misleadingstatements.

You also have to realize that I didn't get off the boat here
yesterday. And that *you* have little to no exposure to Arctic
conditions and like a lot of other people your imagination is
good, but doesn't match the reality of Arctic living nearly as
closely as you think.

Yes, arctic outdoor air usually has high relative humidity.It has to be, otherwise the snow would sublime.

It doesn't????

Now we've had more than one person claiming the relative
humidity in the Arctic is always low, and you claiming it is
always high. I assure you all that it isn't *necessarily*
either, and that in fact it is fairly easy to experience both
conditions in the Arctic.
But that outdoor air is extremely dry in absolute terms.My psychrometric chart gives 5 grains water per lb dry air for8'F dewpt. Heated to 60'F, that is 6.4% relative humidity.You're gonna need big humidifiers and all the fun they areto maintain (salt build-up, ugh!)

However, if you have *ever* experienced 6% relative humidity,
you know that static just crackles out of everything. You can't
move without generating a charge. Everything you touch gets
zapped. You can't pet the cat, because it will run when you
so much as look at it.

Now, I'm not going to figure out what's wrong with your
calculations, but I have a cat and it jumps on my lap and gets
petted with regularity. So far today we haven't had even one
experience of enough static buildup to cause us to zap each
other (at this temperature, it does happen, though not often).

You can be assured that the relative humidity inside my house is
*not* 6%, or anything close to it.
Furthermore, I suspect that static build-up is more a functionof absolute humidity than relative humidity. Do people havelots of static problems in Phoenix summers?

Which is to say, you don't have any experience with this at all,
but you're willing to attempt definitive statements??? Tsch
tsch.

I lived in Tucson AZ as a teenager. Trust me, in Phoenix they
have *lots* of static problems in the summer!

I spent 20 years living near Fairbanks AK too.

In Fairbanks the relative humidity can be very low. (However,
at the moment... it's 17F and RH is 91%!) But in Fairbanks
there is no source for water vapor /and/ it is commonly -40C or
colder. Fairbanks sits inland several hundreds of miles, right
between two of the largest mountain ranges in North America;
hence the relative humidity is commonly low, with no wind, and
in the winter there are extreme cold temperatures on a regular
basis. Static is a *big* problem when it gets cold, and only a
small problem with it isn't that cold.

Barrow of course is a maritime environment, and with an ocean on
three sides and with a constant wind there is no lack of humidity.
The relative humidity for outside air is rarely ever very low,
mostly because we rarely ever get extreme cold temperatures here
(due to the moderating effect of the Arctic Ocean and the
constant wind).

The effect is that in Fairbanks static is an almost constant
problem, summer and winter, but in Barrow static is rarely a
problem except during extremely cold weather in the winter (and
virtually never during the summer).

Here are some interesting numbers. I've been archiving hourly
weather summaries from NOAA since last winter. I don't get
every hourly report each day, but in nearly 11 months have 6303
records. A quick grep produces the following numbers:

Total records: 6303
100% RH 354
90-99% 1588
80-89% 2256
70-79% 1872
60-69% 214
50-59% 18
40-49% 1

No records indicated less than 45% relative humidity.

I should probably point out that after 2 decades living in the
Interior, I have a few habits regarding static that are useful.
I use an anti-static mat on the floor and the table my computers
sit on have a grounded metal strip running down the front, such
that as I sit here typing, both of my arms are grounded.

And of course one of the reasons I advocate the use of water
solutions with a wetting agent for cleaning circuit boards is
because of the anti-static benefits (which include the effects
of having a film of wetting agent left on the circuit board to
help dissipate any static buildup, a beneficial effect that lasts
for months).

Incidentally, if anyone can find information on how the
ubiquitous pink anti-static plastic came to exist, the above
reference to leaving a wetting agent on the surface of washed
components has an interesting connection, historically. The
idea of mixing a wetting agent into the plastic mix came as a
result of observing that poly-plastic containers attracted less
surface dirt when they were *not* rinsed clean of soap after
washing. The same applies to computer motherboards.

--
FloydL. Davidson <http://web.newsguy.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska) floyd@barrow.com

[Floyd L. Davidson]

Keith R. Williams <krw@att.bizzzz> wrote:In article <87is8vm9tz.fld@barrow.com>, floyd@barrow.com says... "Watson A.Name - \"Watt Sun, the Dark Remover\"" <NOSPAM@dslextreme.com> wrote:Which is ALL the time where you live! You've gotta be _kidding_ withthis post! That is so ignorant that it is a joke: Barrow, Wiley Post-Will Rogers Memorial Airport, AK, United States (PABR) 71-17-07N 156-45-57W 10M Weather reported at: Thu Oct 28 01:44:00 2004 AKDT ... Temperature : 12 F (-11 C) Dew Point : 8 F (-13 C) *Relative* *Humidity* : *85%* Pressure (altimeter): 29.63 in. Hg (1003 hPa) -- http://weather.noaa.gov/weather/current/PABR.html Do you understand what 85% relative humidity is? It is rather *normal* in a place that sits on a point jutting out into the ocean.What's the RH after you've heated the air to, say, 68F? ;-)Lesse... Actual Vapor Density -------------------- = RH Saturation Vapor DensityAt 14F (close enough) the saturation vapor density is 2.36g/m^3, soyour actual vapor density is: .85 * 2.36g/m^3 or 2.01g/m^3Raise that air to 68F (saturation density = 17.54g/m^3) 2.01g/m^3 -------- = 11% RH 17.5g/m^3...seems pretty dry to me. ;-)

That would indeed be pretty dry. Now, your next assignment is
to figure out why the air in my house *isn't* that dry! ;-)

--
FloydL. Davidson <http://web.newsguy.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska) floyd@barrow.com

[Rob Stow]

Floyd L. Davidson wrote: In Fairbanks the relative humidity can be very low. (However, at the moment... it's 17F and RH is 91%!) But in Fairbanks there is no source for water vapor /and/ it is commonly -40C or colder. Fairbanks sits inland several hundreds of miles, right between two of the largest mountain ranges in North America; hence the relative humidity is commonly low, with no wind, and in the winter there are extreme cold temperatures on a regular basis. Static is a *big* problem when it gets cold, and only a small problem with it isn't that cold.

In support of that ...

Where I live (Moose Jaw, SK, Canada) isn't 1000+ miles further
south than Fairbanks, but -30'C days are common during Dec,
Jan, and Feb, and most years we get a few days of -40'C weather.
100% or near %100 relative humidity on days like that is nothing
unusual - *outdoors*.

It takes trivial amounts of moisture in the air to cause near
100% RH at low temperatures like that. When it is -30'C and
100% RH, there is so little water in the air that if you heated
a volume of that air up to room temperature the RH would fall
to near zero.

However, except when guys like me do crazy overclocking experiments
outdoors on a cold day, the outdoor relative humidity is irrelevant.
It is the RH *indoors* that matters, and the colder it gets outside,
the harder it is to maintain a sufficient RH inside. Warm air is
constantly leaking out around doors and windows, up the chimney,
etc, and carrying away lots of water with it. If the water is not
replenished, such as by a humidifier mounted on the furnace, it is
very easy to have a 20% RH indoors even when the outdoor RH is close
to 100%.

Over the three coldest months of the year the humidifier for my
tiny 800 square foot apartment goes through about 6 liters of water
per day if I want to maintain a 40% RH. And that is over and
above the humidity replenished by things like cooking, bathing,
and simply breathing.


--
BOYCOTT GOOGLE !
Partners in crime with the scum that rules China.
http://www.cnn.com/2004/TECH/internet/09/27/google.china.ap/

[keith]

In article <87acu6n4oi.fld@barrow.com>, floyd@barrow.com says... Keith R. Williams <krw@att.bizzzz> wrote:In article <87is8vm9tz.fld@barrow.com>, floyd@barrow.com says... "Watson A.Name - \"Watt Sun, the Dark Remover\"" <NOSPAM@dslextreme.com> wrote: >Which is ALL the time where you live! You've gotta be _kidding_ with >this post! That is so ignorant that it is a joke: Barrow, Wiley Post-Will Rogers Memorial Airport, AK, United States (PABR) 71-17-07N 156-45-57W 10M Weather reported at: Thu Oct 28 01:44:00 2004 AKDT ... Temperature : 12 F (-11 C) Dew Point : 8 F (-13 C) *Relative* *Humidity* : *85%* Pressure (altimeter): 29.63 in. Hg (1003 hPa) -- http://weather.noaa.gov/weather/current/PABR.html Do you understand what 85% relative humidity is? It is rather *normal* in a place that sits on a point jutting out into the ocean.What's the RH after you've heated the air to, say, 68F? ;-)Lesse... Actual Vapor Density -------------------- = RH Saturation Vapor DensityAt 14F (close enough) the saturation vapor density is 2.36g/m^3, soyour actual vapor density is: .85 * 2.36g/m^3 or 2.01g/m^3Raise that air to 68F (saturation density = 17.54g/m^3) 2.01g/m^3 -------- = 11% RH 17.5g/m^3...seems pretty dry to me. ;-) That would indeed be pretty dry. Now, your next assignment is to figure out why the air in my house *isn't* that dry! ;-)

You only heat your house to 32F (RH=44%)? ;-)

Seriously, your washing of circuit boards isn't as silly as people here
seem to think. The manufacturer washes flux off in what amounts to a
dish-washer. I don't think I'd want to leave a soap residue though.
Analogs certainly wouldn't like that much. A DI or distilled water
rinse would seem appropriate.

BTW, that's first-aid for electronics (and even cameras) after being
dropped in water. Take out the batteries immediately, then dunk in DI
or distilled water as soon as practical. ...cook on low heat until
done.

--
Keith

[Rob Stow]

Keith R. Williams wrote: BTW, that's first-aid for electronics (and even cameras) after being dropped in water. Take out the batteries immediately, then dunk in DI or distilled water as soon as practical. ...cook on low heat until done.

Great for my little digital hearing aid too. At $65
per incident there is no way I'm going to take it to
the service center every time it gets a little sweat
in it and starts making everything sound like
exceptionally bad rap music. And at $2100 that hearing
aid costs a lot more than most desktop computers do.

In the summer, after rinsing things like that they dry
out quickly and safely if I lock them in the car for
an hour or so on a sunny day :-)

--
BOYCOTT GOOGLE !
Partners in crime with the scum that rules China.
http://www.cnn.com/2004/TECH/internet/09/27/google.china.ap/

[Robert Redelmeier]

In comp.sys.ibm.pc.hardware.chips Floyd L. Davidson <floyd@barrow.com> wrote: And that *you* have little to no exposure to Arctic conditions

An incorrect assumption on your part. I've lived where -40'
was a normal temperature, and 0'F was a heatwave. Square
tires, double plug-ins, and driving with the windows open.
Ice-fog around open water. Now, I live someplace warmer.
It doesn't????

It does, particularly on the east side of the Rockies.
you claiming it is always high.

Always is a strong word I avoid using. It is possible to
get low RH cold air, but only by being colder first. Like
-80'F warming to -40'.
However, if you have *ever* experienced 6% relative humidity, you know that static just crackles out of everything.

Yep!
You can't move without generating a charge. Everything you touch gets zapped. You can't pet the cat, because it will run when you so much as look at it.

And hair stands up at a distance.
Now, I'm not going to figure out what's wrong with your calculations,

I doubt anything is wrong with the calcs, but the assumptions
might be mistaken. If you're running a humidifier (wet rug)
or have a tightly sealed house, of course the humidity is
going to be higher. As would [ice] fog.
I lived in Tucson AZ as a teenager. Trust me, in Phoenix they have *lots* of static problems in the summer!

Thanks for the data.

-- Robert

[Floyd L. Davidson]

Keith R. Williams <krw@att.bizzzz> wrote:You only heat your house to 32F (RH=44%)? ;-)

:-)

http://web.newsguy.com/floyd_davidson/sensors/cfdataH.png

(If you want to see what that is all about, though totally
unrelated to this thread,

http://web.newsguy.com/floyd_davidson/sensors/index.html

shows several other plots.)
Seriously, your washing of circuit boards isn't as silly as people hereseem to think. The manufacturer washes flux off in what amounts to a

Pro's have beening doing that since day one. It was a little
difficult back in the days of electron tubes because only the
highest quality equipment used hermetically sealed coils and
such, so only the high quality equipment could be put into a
dish washer. We used to do it all the time with various
components of troposcatter radio systems, and for years and
years I had the most sensitive tropo receiver in Alaska. (This
was reported year after year by the QC inspections, and I got
lots of questions about how and why, but (you guessed it) they
didn't believe me... :-)
dish-washer. I don't think I'd want to leave a soap residue though.Analogs certainly wouldn't like that much. A DI or distilled waterrinse would seem appropriate.

Actually, you *do* want to leave a film of wetting agent on your
motherboard. That will retain just enough moisture to dissipate
static buildup (for example from the air blown into the case by
fans) and will reduce the amount of dust that is attracted and
sticking to the motherboard.

It has about the same effect as an air ionizer.

Which is to say, the motherboard will stay cleaner for longer.
BTW, that's first-aid for electronics (and even cameras) after beingdropped in water. Take out the batteries immediately, then dunk in DIor distilled water as soon as practical. ...cook on low heat untildone.

Incidentally... that is true of gasoline engines too!

--
FloydL. Davidson <http://web.newsguy.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska) floyd@barrow.com

[CBFalconer]

"Floyd L. Davidson" wrote: Keith R. Williams <krw@att.bizzzz> wrote:
.... snip ... What's the RH after you've heated the air to, say, 68F? ;-) Lesse... Actual Vapor Density -------------------- = RH Saturation Vapor Density At 14F (close enough) the saturation vapor density is 2.36g/m^3, so your actual vapor density is: .85 * 2.36g/m^3 or 2.01g/m^3 Raise that air to 68F (saturation density = 17.54g/m^3) 2.01g/m^3 -------- = 11% RH 17.5g/m^3 ...seems pretty dry to me. ;-) That would indeed be pretty dry. Now, your next assignment is to figure out why the air in my house *isn't* that dry! ;-)

One (of many) possibilities is you don't knock the snow off your
boots when you come in from the two-holer. :-) Or you keep a wet
dog in front of the fire.

--
Chuck F (cbfalconer@yahoo.com) (cbfalconer@worldnet.att.net)
Available for consulting/temporary embedded and systems.
<http://cbfalconer.home.att.net> USE worldnet address!

[Floyd L. Davidson]

Rob Stow <rob.stow.nospam@shaw.ca> wrote:Floyd L. Davidson wrote: In Fairbanks the relative humidity can be very low. (However, at the moment... it's 17F and RH is 91%!) But in Fairbanks there is no source for water vapor /and/ it is commonly -40C or colder. Fairbanks sits inland several hundreds of miles, right between two of the largest mountain ranges in North America; hence the relative humidity is commonly low, with no wind, and in the winter there are extreme cold temperatures on a regular basis. Static is a *big* problem when it gets cold, and only a small problem with it isn't that cold.In support of that ...Where I live (Moose Jaw, SK, Canada) isn't 1000+ miles furthersouth than Fairbanks, but -30'C days are common during Dec,Jan, and Feb, and most years we get a few days of -40'C weather.100% or near %100 relative humidity on days like that is nothingunusual - *outdoors*.It takes trivial amounts of moisture in the air to cause near100% RH at low temperatures like that. When it is -30'C and100% RH, there is so little water in the air that if you heateda volume of that air up to room temperature the RH would fallto near zero.However, except when guys like me do crazy overclocking experimentsoutdoors on a cold day, the outdoor relative humidity is irrelevant.It is the RH *indoors* that matters, and the colder it gets outside,the harder it is to maintain a sufficient RH inside. Warm air isconstantly leaking out around doors and windows, up the chimney,etc, and carrying away lots of water with it. If the water is notreplenished, such as by a humidifier mounted on the furnace, it isvery easy to have a 20% RH indoors even when the outdoor RH is closeto 100%.Over the three coldest months of the year the humidifier for mytiny 800 square foot apartment goes through about 6 liters of waterper day if I want to maintain a 40% RH. And that is over andabove the humidity replenished by things like cooking, bathing,and simply breathing.

That is all true.

The two biggest factors controlling inside RH are the vapor
barrier and the type of heating used.

I'd imagine that in northern parts of Canada, just as here in
Alaska, buildings have *very* good vapor barriers. That is as
opposed to what is used in the Lower-48, where they think the
foil backing on fiber insulation is sufficient (and it is,
there!).

Of course having baseboard heat and a boiler that has the air
intake vented from the outside is also a *big* plus for
maintaining a higher RH inside.

When I lived in Fairbanks we kept a large water container on
the stove top all winter long. We burned coal for heat until
the last couple years I was there.

Here I have forced air, but it burns natural gas, and there are
only a few days of the year when the RH gets too low, so I
haven't bothered to do anything special.

--
FloydL. Davidson <http://web.newsguy.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska) floyd@barrow.com

[Robert Redelmeier]

In comp.sys.ibm.pc.hardware.chips Keith R. Williams <krw@att.bizzzz> wrote: I thought "fixer" was sodium thiosulfate and some other stuff. Sodium Hypochlorite is laundry bleach and pool chlorine.

Exactly right. Pretty good for a non-chemist.

-- Robert

[Floyd L. Davidson]

CBFalconer <cbfalconer@yahoo.com> wrote:"Floyd L. Davidson" wrote: Keith R. Williams <krw@att.bizzzz> wrote:... snip ... What's the RH after you've heated the air to, say, 68F? ;-) Lesse... Actual Vapor Density -------------------- = RH Saturation Vapor Density At 14F (close enough) the saturation vapor density is 2.36g/m^3, so your actual vapor density is: .85 * 2.36g/m^3 or 2.01g/m^3 Raise that air to 68F (saturation density = 17.54g/m^3) 2.01g/m^3 -------- = 11% RH 17.5g/m^3 ...seems pretty dry to me. ;-) That would indeed be pretty dry. Now, your next assignment is to figure out why the air in my house *isn't* that dry! ;-)One (of many) possibilities is you don't knock the snow off yourboots when you come in from the two-holer. :-) Or you keep a wetdog in front of the fire.

How much effect do you figure the swimming pool in the basement
has?

Or the hot tub with three cuties in it splashing around?

And that sauna is always attracting a crowd too...

It's difficult to slow down long enough to count the ways... ;-)

--
FloydL. Davidson <http://web.newsguy.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska) floyd@barrow.com

[Floyd L. Davidson]

Robert Redelmeier <redelm@ev1.net.invalid> wrote:In comp.sys.ibm.pc.hardware.chips Floyd L. Davidson <floyd@barrow.com> wrote: And that *you* have little to no exposure to Arctic conditionsAn incorrect assumption on your part. I've lived where -40'was a normal temperature, and 0'F was a heatwave. Squaretires, double plug-ins, and driving with the windows open.Ice-fog around open water. Now, I live someplace warmer.

Interesting, given the mix of serious science and lack of
awareness of some of the more common effects.
It doesn't????It does, particularly on the east side of the Rockies. you claiming it is always high.Always is a strong word I avoid using. It is possible toget low RH cold air, but only by being colder first. Like-80'F warming to -40'.

But think about all those moisture laden clouds swirling around
south of the Alaska Range on an average day in January... and
how high they have to get before they can move across the
mountains (roughly 10,000 feet) and appear over Fairbanks. (And
the same effect for any air from north of Fairbanks coming from
up here on the North Slope.)

I'm sure the temperature change has an effect, but probably
more significant in that particular case is the pressure
change.

The typical winter air in Fairbanks moves from the Bering Sea
inland along the north side of the Alaska Range though, and I
suppose it is the temperature changes that dry it out so
thoroughly by the time it gets that far inland.
However, if you have *ever* experienced 6% relative humidity, you know that static just crackles out of everything.Yep! You can't move without generating a charge. Everything you touch gets zapped. You can't pet the cat, because it will run when you so much as look at it.And hair stands up at a distance. Now, I'm not going to figure out what's wrong with your calculations,I doubt anything is wrong with the calcs, but the assumptionsmight be mistaken.

The calcs are flawed. You are indeed using the mistaken
assumption that what you calculated would be the RH of the air
inside a house, and that isn't the case. You calculated the RH
of air in a container as the temperature changed, with no other
source of moisture and no exchange of air. Houses don't fit.
If you're running a humidifier (wet rug)or have a tightly sealed house, of course the humidity isgoing to be higher. As would [ice] fog.

There are few houses (and all are old) here that are *not*
tightly sealed. In fact sealing them up too tight is more often
a problem these days than the other way around. (Which is
something that has changed in the past 3-4 decades.)
I lived in Tucson AZ as a teenager. Trust me, in Phoenix they have *lots* of static problems in the summer!Thanks for the data.

They get something we never see here, which is lightning strikes
that hit the ground. We've had three thunder storms here in
the past 5 years, and it had been 20 years before that, but what
little lightning we ever do get is strictly between clouds.

In Tucson there are localized lightning storms all summer long.
It starts every afternoon about 1-3 PM as the air begins to cool
off from the peak heat of the day. Really dramatic!

I'm not sure what is normal there now, but in the 50's and 60's
most homes were cooled with evaporative cooling, so the RH
inside most homes would have been fairly high. Of course the RH
of the outside temperature is often less than 20%

--
FloydL. Davidson <http://web.newsguy.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska) floyd@barrow.com

[Robert Redelmeier]

In comp.sys.ibm.pc.hardware.chips Floyd L. Davidson <floyd@barrow.com> wrote: Interesting, given the mix of serious science and lack of awareness of some of the more common effects.

It's easy to overlook the common.
But think about all those moisture laden clouds swirling around

Most of the moisture in clouds (even at warmer latitudes)
is as ice crystals. Even if the ground temp is 60'F, around
8,000 ft, the temp has dropped below freezing (adiabatic
lapse rate). Most (not all) clouds hang out 10-30 kft.
inside a house, and that isn't the case. You calculated the RH of air in a container as the temperature changed, with no other source of moisture and no exchange of air. Houses don't fit.

OK. What does? How many air changes with outside per hour
(or per day) does your house do? How many lb/hr of internal
water vaporisation? Assumptions are made to simplify, but
may not fit. Then you need more data.
There are few houses (and all are old) here that are *not* tightly sealed. In fact sealing them up too tight is more often a problem these days than the other way around. (Which is something that has changed in the past 3-4 decades.)

I don't doubt it. Perhaps to some mild toxicity.
They get something we never see here, which is lightning strikes that hit the ground. We've had three thunder storms here in the past 5 years, and it had been 20 years before that, but what little lightning we ever do get is strictly between clouds.

Yes, I'm aware of that. Rather unsettling, thunder during
winter. But lightening storms are _not_ what we're talking
about here. The US Gulf Coast has plenty of those, but few
problems from local static build-up that might threaten
circuits. Does Phoenix in summer?
60's most homes were cooled with evaporative cooling,

Swamp coolers.

-- Robert

[Floyd L. Davidson]

Robert Redelmeier <redelm@ev1.net.invalid> wrote: They get something we never see here, which is lightning strikes that hit the ground. We've had three thunder storms here in the past 5 years, and it had been 20 years before that, but what little lightning we ever do get is strictly between clouds.Yes, I'm aware of that. Rather unsettling, thunder duringwinter. But lightening storms are _not_ what we're talking

What has *winter* got to do with it? Hell will freeze over
before there is a thunderstorm here in the winter.
about here. The US Gulf Coast has plenty of those, but fewproblems from local static build-up that might threatencircuits. Does Phoenix in summer?

Yes. It is very dry there.

--
FloydL. Davidson <http://web.newsguy.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska) floyd@barrow.com

[keith]

On Thu, 28 Oct 2004 20:02:15 +0000, Robert Redelmeier wrote:
In comp.sys.ibm.pc.hardware.chips Keith R. Williams <krw@att.bizzzz> wrote: I thought "fixer" was sodium thiosulfate and some other stuff. Sodium Hypochlorite is laundry bleach and pool chlorine. Exactly right. Pretty good for a non-chemist.

I was quite the neighborhood chemist (and b00mb maker) some
forty years ago. ;-)

I *hated* freshman chemistry though. No bangs, too much gunk. Boooring!

--
Keith

[Gumby]

lots of vacuum cleaners have a metal tube the attachmentsgo to, just ground the tube to the same ground as thePC. 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!).

So delay doing this job until the next really humid day....

[Gumby]

Greg wrote:
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!

Some cpu coolers are much more liable to clog with dust than
others. I have a Alpha PAL8045, it looks sort of like the
surface of a hair brush (lots of metal pins). That's the only
component I try to clean of dust once a year or so.

[chrisv]

Robert Redelmeier <redelm@ev1.net.invalid> wrote:
There are few houses (and all are old) here that are *not* tightly sealed. In fact sealing them up too tight is more often a problem these days than the other way around. (Which is something that has changed in the past 3-4 decades.)I don't doubt it. Perhaps to some mild toxicity.

Not in my house. I have a mechanical ventilation system, with an
air-to-air heat exchanger. Having one is starting to become code, in
new builds, in my area. I had it built-into my house even though it
was not required at the time.

[Robert Redelmeier]

In comp.sys.ibm.pc.hardware.chips chrisv <chrisv@nospam.invalid> wrote: Not in my house. I have a mechanical ventilation system, with an air-to-air heat exchanger. Having one is starting to become code, in new builds, in my area. I had it built-into my house even though it was not required at the time.

Good for you. But that xchr won't exchange humidity.

-- Robert

[chrisv]

Robert Redelmeier <redelm@ev1.net.invalid> wrote:
In comp.sys.ibm.pc.hardware.chips chrisv <chrisv@nospam.invalid> wrote: Not in my house. I have a mechanical ventilation system, with an air-to-air heat exchanger. Having one is starting to become code, in new builds, in my area. I had it built-into my house even though it was not required at the time.Good for you. But that xchr won't exchange humidity.

Indeed. The net effect is that the air in the house is significantly
dryer than it otherwise would be. This, in fact, is the system's main
purpose. People may prefer more water in the air, but the house does
not, as it can lead to condensation in the walls, with subsequent mold
and bacterial growth.

[Robert Redelmeier]

In comp.sys.ibm.pc.hardware.chips chrisv <chrisv@nospam.invalid> wrote: Indeed. The net effect is that the air in the house is significantly dryer than it otherwise would be. This, in fact, is the system's main purpose. People may prefer more water in the air, but the house does not, as it can lead to condensation in the walls, with subsequent mold and bacterial growth.

Is the house to keep people comfortable, or itself pristine?

I thought condensation in walls is primarily a result a
defects in the vapor barrier and/or improper (too much/little)
ventillation of the insulation spaces. Why make people
uncomfortable to accomodate construction defects?

-- Robert

[Floyd L. Davidson]

Robert Redelmeier <redelm@ev1.net.invalid> wrote:In comp.sys.ibm.pc.hardware.chips chrisv <chrisv@nospam.invalid> wrote: Not in my house. I have a mechanical ventilation system, with an air-to-air heat exchanger. Having one is starting to become code, in new builds, in my area. I had it built-into my house even though it was not required at the time.Good for you. But that xchr won't exchange humidity.

Which is good, because that keeps the moisture *in* the house.

--
FloydL. Davidson <http://web.newsguy.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska) floyd@barrow.com

[chrisv]

Robert Redelmeier <redelm@ev1.net.invalid> wrote:
In comp.sys.ibm.pc.hardware.chips chrisv <chrisv@nospam.invalid> wrote: Indeed. The net effect is that the air in the house is significantly dryer than it otherwise would be. This, in fact, is the system's main purpose. People may prefer more water in the air, but the house does not, as it can lead to condensation in the walls, with subsequent mold and bacterial growth.Is the house to keep people comfortable, or itself pristine?

You may not be too comfortable breathing excessive mold spores.
Ripping out rotted or moldy walls is also not fun or cheap.
I thought condensation in walls is primarily a result adefects in the vapor barrier and/or improper (too much/little)ventillation of the insulation spaces.

Contributing factors, to be sure. In practice, it's very difficult to
keep interior moisture from penetrating the walls. Areas around
electrical outlets and windows, both interruptions in the vapor
barrier, are largely to blame.

A tightly sealed house can get quite humid in the Winter, what with
people breathing, taking showers, cooking with gas, doing laundry,
etc. Condensation on your windows is evidence of excessive moisture.
Why make peopleuncomfortable to accomodate construction defects?

I'm not uncomfortable, although some may be more sensitive...

[Robert Redelmeier]

In comp.sys.ibm.pc.hardware.chips chrisv <chrisv@nospam.invalid> wrote: Condensation on your windows is evidence of excessive moisture.

That's more a function of window insulating value, outside
temp and wind. I've had windows frost up even at 20% RH,
but now my windows condense on the _outside_ :)

-- Robert

[Floyd L. Davidson]

chrisv <chrisv@nospam.invalid> wrote:Robert Redelmeier <redelm@ev1.net.invalid> wrote:In comp.sys.ibm.pc.hardware.chips chrisv <chrisv@nospam.invalid> wrote: Not in my house. I have a mechanical ventilation system, with an air-to-air heat exchanger. Having one is starting to become code, in new builds, in my area. I had it built-into my house even though it was not required at the time.Good for you. But that xchr won't exchange humidity.Indeed. The net effect is that the air in the house is significantlydryer than it otherwise would be. This, in fact, is the system's mainpurpose. People may prefer more water in the air, but the house doesnot, as it can lead to condensation in the walls, with subsequent moldand bacterial growth.

What kind of climate conditions are you dealing with?

Most of the discussion so far as been about situations where the
outside air is colder than the inside air. In that case the
inside air is heated, and the relative humidity drops as the
temperature rises simply because the air can hold more moisture
at warmer temperatures. (The actual amount of moisture doesn't
change because of temperature, as such. But...)

If, as is usually the case, more moisture is indeed added to the
air inside the house via a humidifier perhaps, but also just due
to normal activities such as running a washing machine, taking a
shower, etc., the amount of moisture in the inside air is higher
than can be maintained if the air is cooled to outside
temperatures. (Assuming that outside air is indeed cooler...)
The result is condensation as the air is cooled, at the location
where that takes place. That, for example, can commonly be
seen, when the weather is cold enough, as frost that forms in an
unheated porch on the ceiling or even the walls close to the
door. Everytime the door is opened a mass of moist warm air
rushes out, cools off, the moisture condenses, and forms frost
on the first surface it touches.

The same thing happens *any* place that inside air leaks to the
outside, and if that is in your wall, that is where the frost
forms. Common locations are breaks in the vapor barrier for
electrical wiring, usually around lighting fixures, wall mounted
switches or sockets. After a prolonged cold period, water
dripping from a ceiling light fixture in a room than has cold
air directly above the ceiling is a very good indication that
there is a significant leak in the vapor barrier. Foam
insulation is a good cure...

The vapor pressure is greater as the temperature difference
increases on each side of the vapor barrier. That means a vapor
barrier which would be fine for a wall that will never see more
than say 70F degrees difference in temperature (75F inside and
+5F outside) might not work well at all where the outside
temperature goes down to -45F, and the difference becomes 110F
degrees!

Indeed, typical fiberglass insulation is sold with a foil
backing that is perhaps an adaquate vapor barrier for a 70F
degree difference, but leaks like a sieve when the difference is
110F degrees. Carefully applied sheets of visqueen plastic with
*no* holes, and overlapping edges are used in such circumstance.
Likewise sprayed on foam insulation is also a good vapor
barrier.

What you've described sounds like a seriously faulty vapor
barrier. The air-to-air heat exchanger should allow you to
maintain a *higher* relative humidity inside the house than
otherwise would be possible. (Assuming colder outside
temperatures; though perhaps you have exactly the opposite???
That might require an entirely different construction technique
as far as insulation and where the vapor barrier is placed.)

--
FloydL. Davidson <http://web.newsguy.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska) floyd@barrow.com

[Floyd L. Davidson]

chrisv <chrisv@nospam.invalid> wrote:Robert Redelmeier <redelm@ev1.net.invalid> wrote:I thought condensation in walls is primarily a result adefects in the vapor barrier and/or improper (too much/little)ventillation of the insulation spaces.Contributing factors, to be sure. In practice, it's very difficult tokeep interior moisture from penetrating the walls. Areas aroundelectrical outlets and windows, both interruptions in the vaporbarrier, are largely to blame.

Actually it is fairly easy to keep interior moisture out of the
walls, but it means using the right construction practices to
begin with! Trying to fix it later can be, errr, interesting.

If you have the problems described, it is very likely that
careful application of foam insulation sprayed behind the
various electrical fixtures, can cure it. Getting that right
the first time is important though, because one you block off
the easy access to that area with foam, it gets harder to try a
second application!

I lived near Fairbanks for a couple decades, in a house that had
an unheated crawl space in the area between the ceiling and the
roof. It turned out that a "hatch" going up through a closet to
that area, and two of the several ceiling mounted light
fixtures, were leaking massive amounts of moisture filled air up
into the crawl space. By the second or third warm period we had
water dripping out of the light fixtures. (I didn't even see
the "hatch", until I crawled around up there to fix the lights
and discovered the hatch from to top.)

I lifted the insulation up from between the joists, sprayed the
entire area on top of each electrical fixture, and put the
insulation back down. Never had another problem.

The hatch took a little more doing. I lifted all the insulation
on both sides and directly over it, and put in a layer of
plastic sheeting that extended 2 feet farther than the cracks,
in every direction and then put the insulation back down. That
cured that one.
A tightly sealed house can get quite humid in the Winter, what withpeople breathing, taking showers, cooking with gas, doing laundry,etc. Condensation on your windows is evidence of excessive moisture.

Condensation on your windows merely indicates you've got single
pane glass windows in a climate where double or even triple
panes should be used! (Or that the window isn't shut tightly
enough.)
Why make peopleuncomfortable to accomodate construction defects?I'm not uncomfortable, although some may be more sensitive...

Fix the problems though, not the symptoms.

--
FloydL. Davidson <http://web.newsguy.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska) floyd@barrow.com

[Al Dykes]

In article <2u9h8qF27roerU1@uni-berlin.de>,
Cuzman <cuzNOSPAM@supanet.com> wrote:"Sammo" <noone@no-where.com> wrote in messagenews:958F7E6A631A81A7D4@204.153.244.156..." In terms of static, how safe is it to clean inside a home PC by using avacuum cleaner? "IMO it's still not safe at all. Buy a can of compressed-air from anelectrical hardware store.


Staples and Office Depot have cans of air. Costco has them dirt cheap,
buy you need to buy a truckload.

One full size can will clean out several computers.

vacuums generate static charge. A discharge below the level of human
perception can damage semiconductors.
--
a d y k e s @ p a n i x . c o m
----

[Al Dykes]

In article <87lldsnrre.fld@barrow.com>,
Floyd L. Davidson <floyd@barrow.com> wrote:Sammo <noone@no-where.com> wrote:In terms of static, how safe is it to clean inside a home PC by usinga vacuum cleaner?Some people like this website suggest that it is unwise.http://www.dansdata.com/sbs3.htmThe web page descriptions are indeed fairly funny, if you knowwhat they are talking about. But I highly suspect anyone with alimited background in Electro Static Discharge will be moreconfused than not.If my PC is switched off but remains earthed (to the mains earth) andI am careful not to do physical damage to the PC with my home vacuumcleaner, 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 staticcharge on any component that is an insulator.Hence *compressed* *dry* *air* and *vacuum* *cleaners* are notgood ideas. In fact, compressed air might be worse because itcan forcefully blast dust into places it wouldn't otherwise go.If you get enough charge (a few thousand volts, for example, iscommon), it will then break down the insulation between thecharge and the next nearest object that is either also holding acharge 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 currentinduced into other conductors as a result of that current.The way to get the dust out of a computer case safely is to usea damp rag to manually pick up dust. It shouldn't be so wetthat it drips moisture (though that isn't necessarily badeither, see below), but needs to be damp enough that dust willstick to it and static cannot build up on it. I personallyprefer to have a large bowl of water mixed with a littlehousehold cleaner (such as 409 or Mr. Clean), in which the dustrag (a well worn bathroom wash cloth or a thin dish towel, isnice) is washed as it get dirty. The soapy water in the bowlshould be changed somewhat regularly too, i.e. when it gets sodirty that as much dirt moves from the water to the rag as fromthe rag to the water!Which type of soap to use does make a difference. The idea issomething that will dissolve any grease film or other coatingthat might be present, but even more important is that it be agood water dispersant. Automatic dishwater soap is perhaps thebest in that respect.


I've worked with professional disaster cleanup crews that use
deionized distilled water with a pressure washer, set at modest
pressure. Nothing added. Immediatly after the component is hosed off
they pop the item is a standard commercial convection oven set to
about 160F for a few minutes.

As a practical matter, I see no problem with cans of compressed gas.
Use a wrist strap if the equimpment is made of unreplacableium.


--
a d y k e s @ p a n i x . c o m
----

[Floyd L. Davidson]

adykes@panix.com (Al Dykes) wrote:Floyd L. Davidson <floyd@barrow.com> wrote:*Moving* *dry* *air* around is a great way to build up a staticcharge on any component that is an insulator.Hence *compressed* *dry* *air* and *vacuum* *cleaners* are notgood ideas. In fact, compressed air might be worse because itcan forcefully blast dust into places it wouldn't otherwise go.

[ lots of stuff we agree on snipped ]
As a practical matter, I see no problem with cans of compressed gas.Use a wrist strap if the equimpment is made of unreplacableium.

There are two problems with cans of compressed gas. One is just
moving dry air around is, all by itself, a way to generate a
static charge.

The other is that any blast of air can force dirt particles into
places that they don't come out of. That isn't the worst thing
in the world, but it can occasionally have bad effects. There
aren't typically many things in a computer where it is likely to
do anything though. (The place that always annoyed me when
someone used compressed air was in any rack full of
"miscellaneous drop equipment" in a long distance telephone
office. Which is to say, a rack full of relays. Relays full of
dust particles become high maintenance items...)

--
FloydL. Davidson <http://web.newsguy.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska) floyd@barrow.com

[John]

On 29 Oct 2004 22:17:16 -0400, adykes@panix.com (Al Dykes)
wrote:
In article <2u9h8qF27roerU1@uni-berlin.de>,Cuzman <cuzNOSPAM@supanet.com> wrote:"Sammo" <noone@no-where.com> wrote in messagenews:958F7E6A631A81A7D4@204.153.244.156..." In terms of static, how safe is it to clean inside a home PC by using avacuum cleaner? "IMO it's still not safe at all. Buy a can of compressed-air from anelectrical hardware store.Staples and Office Depot have cans of air. Costco has them dirt cheap,buy you need to buy a truckload.One full size can will clean out several computers.vacuums generate static charge. A discharge below the level of humanperception can damage semiconductors.

Officemax and Office Depot(?) used to have them FAR, I have
a drawer full that were free.

[Franc Zabkar]

On Wed, 27 Oct 2004 06:46:13 -0800, floyd@barrow.com (Floyd L.
Davidson) put finger to keyboard and composed:
Sammo <noone@no-where.com> wrote:In terms of static, how safe is it to clean inside a home PC by usinga vacuum cleaner?
*Moving* *dry* *air* around is a great way to build up a staticcharge on any component that is an insulator.Hence *compressed* *dry* *air* and *vacuum* *cleaners* are notgood ideas. In fact, compressed air might be worse because itcan forcefully blast dust into places it wouldn't otherwise go.

I don't have an opinion either way, but I offer the following two
observations.

(1) Fans blow air across the motherboard and at expensive components
all day long.

(2) Technicians use a heat gun (which blows very hot dry air) when
troubleshooting thermally sensitive components.
The way to get the dust out of a computer case safely is to usea damp rag to manually pick up dust. It shouldn't be so wetthat it drips moisture (though that isn't necessarily badeither, see below), but needs to be damp enough that dust willstick to it and static cannot build up on it.

When cleaning dirty electronic appliances I brush the PCBs with
isopropyl alcohol, or methylated spirits if isopropyl is unavailable.
When cleaning the insides of TVs and other very dusty equipment I use
a vacuum cleaner because any other method just wouldn't be expedient,
IMO.


- Franc Zabkar
--
Please remove one 's' from my address when replying by email.

[Floyd L. Davidson]

Franc Zabkar <fzabkar@optussnet.com.au> wrote:On Wed, 27 Oct 2004 06:46:13 -0800, floyd@barrow.com (Floyd L.Davidson) put finger to keyboard and composed:Sammo <noone@no-where.com> wrote:In terms of static, how safe is it to clean inside a home PC by usinga vacuum cleaner?*Moving* *dry* *air* around is a great way to build up a staticcharge on any component that is an insulator.Hence *compressed* *dry* *air* and *vacuum* *cleaners* are notgood ideas. In fact, compressed air might be worse because itcan forcefully blast dust into places it wouldn't otherwise go.I don't have an opinion either way, but I offer the following twoobservations.(1) Fans blow air across the motherboard and at expensive componentsall day long.

There are several important differences though. The two most
important are that the air is not drier than the surrounding air
and that the volume and speed of air on any given component is
very small over a long period of time.

Compare that to either a vacuum or a compressed air source, and
the difference is great (as far as generating a static charge).
(2) Technicians use a heat gun (which blows very hot dry air) whentroubleshooting thermally sensitive components.

That is a relatively poor practice.

In both instances above though, note that the equipment is
powered up, which means that it is definitely grounded and
relatively able to disperse any charge build up.
The way to get the dust out of a computer case safely is to usea damp rag to manually pick up dust. It shouldn't be so wetthat it drips moisture (though that isn't necessarily badeither, see below), but needs to be damp enough that dust willstick to it and static cannot build up on it.When cleaning dirty electronic appliances I brush the PCBs withisopropyl alcohol, or methylated spirits if isopropyl is unavailable.

That sounds like an *excellent* technique. "Tuner cleaner"
sprays are also good.
When cleaning the insides of TVs and other very dusty equipment I usea vacuum cleaner because any other method just wouldn't be expedient,IMO.

Not so good... but to be honest, it probably isn't all that bad
either, assuming you have pretty high humidity, which makes all
of these things very forgiving.

If you have very low humidity, or if you do this to a large number
of items, there will be a significant number of related failures.


Reminds me of a story I once heard, from back in the 70s about a
company manufacturing small precision film resistors. They were
experiencing extremely high return rates from out of spec parts.

As part of their probe into what was going on, they decided to
order a test shipment of similar devices from a Japanese
competitor. They ordered up "1000 ea Precision Resistors" and
specified that they would accept no more than 6 percent out of
tolerance. That was the spec they were failing to meet. Much
to their embarrassment, the Japanese folks didn't understand.

They received a box, with two bundles inside. The large one was
labeled "1000 each precision resistors". The smaller one had a
note on it which said something to the effect of "Here are your
6% out of tolerance items." ;-)

They obviously needed to try harder...

What they eventually found was their shipping department was
packaging these thin film resistors in paper envelopes, and the
ESD produced by inserting/removing them was sometimes zapping
the thin film enough to change the resistance. The problem was
fixed by using anti-static plastic packaging.

--
FloydL. Davidson <http://web.newsguy.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska) floyd@barrow.com

[James H. Fox]

"Floyd L. Davidson" <floyd@barrow.com> wrote in message
news:87zn23luea.fld@barrow.com... Reminds me of a story I once heard, from back in the 70s about a company manufacturing small precision film resistors. They were experiencing extremely high return rates from out of spec parts. As part of their probe into what was going on, they decided to order a test shipment of similar devices from a Japanese competitor. They ordered up "1000 ea Precision Resistors" and specified that they would accept no more than 6 percent out of tolerance. That was the spec they were failing to meet. Much to their embarrassment, the Japanese folks didn't understand. They received a box, with two bundles inside. The large one was labeled "1000 each precision resistors". The smaller one had a note on it which said something to the effect of "Here are your 6% out of tolerance items." ;-)

That is too funny. And it is probably true.

[Franklin]

On 27 Oct 2004, =?UTF-8?B?UGFsaW5kcuKYu21l?= wrote:
Electrostatic discharge can produce some intersting effects on semiconductors and the risk shouldn't be discounted. However I have cleaned out the interior of countless cases with no apparent ill effect- using a soft haired paintbrush in one hand whilst hovering over the area with the nozzle of a domestic vacuum cleaner in the other. Due to the nature of the job, one hand or both is in contact with the case most of the time and so there is little chance for static build up on the nozzle/your body/brush. Touching the case before introducing the brush is a good idea. Personally, I prefer to have the case sat on an esd mat to leaving it plugged in - not so much from the static point of view but a marked reluctance to work on anything with power on or connected, unless unavoidable (like, I don't have the mat with me). Not to be done to a laser printer, but for other reasons.

Can you explain why this should not be done to a laser printer,
please.

[Franklin]

On 27 Oct 2004, kony wrote:
Aaaakkk! No! Dishwasher machine soap (Cascade) is one ofthe nastiest cleaners I know. Full of trisodium phosphate,silicates and calcium hypochlorite. Perhaps you meandishwasher anti-spot filming agent (JetDry). This stuffshould be very benign when diluted.Anybody have any good experiences cleaning IBM Model"M" keyboards in a (soapless) dishwasher? What do you consider "nasty" about Dishwasher Detergent? I mean, what harm do you expect? I have cleaned a LOT of boards in a tub of warm water and detergent (dishwasher or whatever was handy) with a paintbrush, it does a great job and the boards worked fine afterwards, still do. Two important things to do though, are removing the battery and EPROM first.



What is so special about an EPROM? Surely it is a prone to damage
from water/detergent as the other chips?

Of course it's also necessary to _completely_ dry the boards, including water wicked under chips and in sockets, which can take a few days or gentle heating.

[keith]

On Wed, 27 Oct 2004 12:25:37 +0100, 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 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?

Absolutely! Just because your sysoem is grounded doesn't mean everythign
inside is. Indeed having it grounded could cause even more problems
(current's gotta go somewhere). If you can feel the shock, it''l destroy
any electronics it's going through.

--
Keith

[John]

On Sun, 31 Oct 2004 00:58:04 +0100, Franklin
<no_thanks@mail.com> wrote:
On 27 Oct 2004, kony wrote:Aaaakkk! No! Dishwasher machine soap (Cascade) is one ofthe nastiest cleaners I know. Full of trisodium phosphate,silicates and calcium hypochlorite. Perhaps you meandishwasher anti-spot filming agent (JetDry). This stuffshould be very benign when diluted.Anybody have any good experiences cleaning IBM Model"M" keyboards in a (soapless) dishwasher? What do you consider "nasty" about Dishwasher Detergent? I mean, what harm do you expect? I have cleaned a LOT of boards in a tub of warm water and detergent (dishwasher or whatever was handy) with a paintbrush, it does a great job and the boards worked fine afterwards, still do. Two important things to do though, are removing the battery and EPROM first.What is so special about an EPROM? Surely it is a prone to damagefrom water/detergent as the other chips?


Perhaps just more sensitive to ESD?
From past experience I've had to reflash BIOS chips that
were left in boards.

[=?UTF-8?B?UGFsaW5kcuKYu21l?=]

Franklin wrote: On 27 Oct 2004, =?UTF-8?B?UGFsaW5kcuKYu21l?= wrote:Electrostatic discharge can produce some intersting effectson semiconductors and the risk shouldn't be discounted.However I have cleaned out the interior of countless caseswith no apparent ill effect- using a soft haired paintbrushin one hand whilst hovering over the area with the nozzle ofa domestic vacuum cleaner in the other. Due to the nature ofthe job, one hand or both is in contact with the case mostof the time and so there is little chance for static buildup on the nozzle/your body/brush. Touching the case beforeintroducing the brush is a good idea.Personally, I prefer to have the case sat on an esd mat toleaving it plugged in - not so much from the static point ofview but a marked reluctance to work on anything with poweron or connected, unless unavoidable (like, I don't have themat with me).Not to be done to a laser printer, but for other reasons. Can you explain why this should not be done to a laser printer, please.


Toner + domestic vacuum cleaner = happy wife*.

*
1) She has probably been nagging to get the old one replaced.

2) Flowers are cheaper and work faster.

--

Sue

2)

[Tzortzakakis Dimitrios]

Critical components of my PC have a guarantee of 3 years, which I find long
enough.RAM has a lifetime guarantee.My vendor didn't tell me anything;I find
opening my PCs case doing more harm than good.Even a very small electric
charge on myself can have irreversible effects on the hardware.Computer
circuits are more sensitive to static, than dust (on my opinion anyway).And
to forceful handling (if you allow me the expression).Just my 700 euro worth
(what my PC did cost).

--
Dimitris Tzortzakakis,Iraklion Crete,Greece
major in electrical engineering-freelance electrician
FH von Iraklion-Kreta, freiberuflicher Elektriker
dimtzort AT otenet DOT gr
? "kony" <spam@spam.com> ?????? ??? ??????
news:n300o0127cbd3gsr5mqvetiqpr02rssqum@4ax.com... On Wed, 27 Oct 2004 22:56:50 +0300, "Tzortzakakis Dimitrios" <dimtzortihatespam@nospamotenet.gr> wrote:Yeah-there's no real reason you need to vacuum your PC.Long before you
havedamage from dust, you will be upgrading to a new PC (say 5 years, which
is amoderate life span for an ordinary PC0luck or unluck this can be up to 7years).Before dust will reach dangerous levels, critical components
shouldfail first.It's not a good idea to open your PC just for cleaning,
though.Myvendor told me these things. It depends a lot on the environment. Too often we assume queries are only related to home PCs but these days almost any business has some too. Your vendor likely told you not to open it to minimize risk of user-induced problems within the warranty period. They expect a system to keep running for that period and don't care as much about longer-term effects. It is a good idea to open and clean a PC at whatever interval is dictated by the environment. Often "cleaning" doesn't mean getting every little spec of dust out, simply checking the primary fans and heatsink(s) for buildup.

[George Macdonald]

On Sun, 31 Oct 2004 00:49:56 +0100, Franklin <no_thanks@mail.com> wrote:
On 27 Oct 2004, =?UTF-8?B?UGFsaW5kcuKYu21l?= wrote: Electrostatic discharge can produce some intersting effects on semiconductors and the risk shouldn't be discounted. However I have cleaned out the interior of countless cases with no apparent ill effect- using a soft haired paintbrush in one hand whilst hovering over the area with the nozzle of a domestic vacuum cleaner in the other. Due to the nature of the job, one hand or both is in contact with the case most of the time and so there is little chance for static build up on the nozzle/your body/brush. Touching the case before introducing the brush is a good idea. Personally, I prefer to have the case sat on an esd mat to leaving it plugged in - not so much from the static point of view but a marked reluctance to work on anything with power on or connected, unless unavoidable (like, I don't have the mat with me). Not to be done to a laser printer, but for other reasons.Can you explain why this should not be done to a laser printer,please.

Hmm, since Sue/Palindr?me's response is kinda cryptic, to say the least
(she? seems to prefer flowers?:-)):

1) It can be bad for you - between the developer, which is finely divided
iron beads and the toner, which is an ammonia hydrocarbon complex, there
are various opinions on its carcinogenic effects. Basically a domestic
vacuum cleaner does not have sufficiently small particle filtration in its
bag/trap to prevent throwing the stuff into the air. Note that there are
strict standards now on the amount of leakage of toner/developer from
modern xerographic process printers/copiers - makes me wonder how much
damage was done or identified in the "bad old days".

2) It can be bad for the vacuum cleaner, depending on its construction and
where the bearings and electric motor are relative to the dirty part of the
suction path. When heated, just like in the fusing part of the printing
process, the toner melts and then solidifies into a nasty gunk.

Rgds, George Macdonald

"Just because they're paranoid doesn't mean you're not psychotic" - Who, me??

[=?UTF-8?B?UGFsaW5kcuKYu21l?=]

George Macdonald wrote: On Sun, 31 Oct 2004 00:49:56 +0100, Franklin <no_thanks@mail.com> wrote:On 27 Oct 2004, =?UTF-8?B?UGFsaW5kcuKYu21l?= wrote:Electrostatic discharge can produce some intersting effectson semiconductors and the risk shouldn't be discounted.However I have cleaned out the interior of countless caseswith no apparent ill effect- using a soft haired paintbrushin one