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The Dust Problem

P

Paul Burridge

Jan 1, 1970
0
Hi guys,

There have been many times IME that a piece of electronic equipmenet
has failed to function altogether or more likely developed some
annoying intermittent fault and the cure was simply to take the lid
off and blast the circuit board(s) with an aerosol of compressed air.
Dust must have been the problem. But why? It's hardly a great
electrical conductor after all.

p.
 
J

Jerry G.

Jan 1, 1970
0
The dust allows for the heat to not dissipate. Some components can overheat
when coated with dust. It makes a sort of insulated coating, something like
wool on your body. Also, the dust can have some dielectric reaction and
effect the performance of high frequency circuits.

--

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


Hi guys,

There have been many times IME that a piece of electronic equipmenet
has failed to function altogether or more likely developed some
annoying intermittent fault and the cure was simply to take the lid
off and blast the circuit board(s) with an aerosol of compressed air.
Dust must have been the problem. But why? It's hardly a great
electrical conductor after all.

p.
 
J

John Woodgate

Jan 1, 1970
0
I read in sci.electronics.design that Jerry G. <[email protected]>
wrote (in <[email protected]>) about 'The Dust Problem',
The dust allows for the heat to not dissipate. Some components can
overheat when coated with dust. It makes a sort of insulated coating,
something like wool on your body. Also, the dust can have some
dielectric reaction and effect the performance of high frequency
circuits.

What really happens is that when you open their cage and clean it out,
you frighten the electrons, so that they are on their best behaviour of
a week or two.
 
P

Phil Hobbs

Jan 1, 1970
0
John said:
I read in sci.electronics.design that Jerry G. <[email protected]>
wrote (in <[email protected]>) about 'The Dust Problem',


What really happens is that when you open their cage and clean it out,
you frighten the electrons, so that they are on their best behaviour of
a week or two.
Dust also absorbs water, leading to lots of nasty surface leakage,
drift, and 1/f noise in damp weather. It will also have ionic
components (e.g. from salt aerosols due to sea spray, salt from skin
flakes, or sulphates from combustion) which make this effect worse.

Cheers,

Phil Hobbs
 
J

John Woodgate

Jan 1, 1970
0
I read in sci.electronics.design that Phil Hobbs <hobbs@SpamMeSenseless.
us.ibm.com> wrote (in said:
Dust also absorbs water, leading to lots of nasty surface leakage,
drift, and 1/f noise in damp weather. It will also have ionic
components (e.g. from salt aerosols due to sea spray, salt from skin

I prefer my explanation - it's less dull. (;-)
 
N

N Cook

Jan 1, 1970
0
Paul Burridge said:
Hi guys,

There have been many times IME that a piece of electronic equipmenet
has failed to function altogether or more likely developed some
annoying intermittent fault and the cure was simply to take the lid
off and blast the circuit board(s) with an aerosol of compressed air.
Dust must have been the problem. But why? It's hardly a great
electrical conductor after all.

p.

Beaten by a whisker
Older data centres and e-government sites should take heed of problems
assailing the Colorado secretary of state's office. A series of computer
outages has been traced to small metallic filaments, known as zinc whiskers.
The fibres form a fuzzy surface on zinc-coated surfaces such as data centre
flooring and ageing computer casings. As the minute filaments detach, they
are sucked into computers by their cooling fans, and can cause power
supplies to short or even cause data errors by shorting out the connectors
on microchips. In Colorado, the resulting downtime prevented electronic
filings of business and elections documents.
http://nepp.nasa.gov [pdf]

source
http://www.guardian.co.uk/online/story/0,3605,1255870,00.html
Thursday July 8, 2004

Not experienced it myself repairing mainly domestic kit
electronic hints and repair briefs
http://homepages.tcp.co.uk/~diverse
 
J

Joerg

Jan 1, 1970
0
Hi Paul,

Most of the dust problems I found were related to contacts not properly
closing anymore because the dust on them prevented it.

Also, much depends on what is in that dust. Folks who clean their pellet
stoves with a brush and not with an ash vacuum will have a lot of soot
in their dust. When they hasten the task and do it while the convection
fan is still going that aggravates the soot content.

Regards, Joerg
 
K

Ken Smith

Jan 1, 1970
0
There have been many times IME that a piece of electronic equipmenet
has failed to function altogether or more likely developed some
annoying intermittent fault and the cure was simply to take the lid
off and blast the circuit board(s) with an aerosol of compressed air.
Dust must have been the problem. But why? It's hardly a great
electrical conductor after all.

Circuits work better after you blow them off because they are hoping you
will do it again.
 
E

E curious

Jan 1, 1970
0
John Woodgate said:
I read in sci.electronics.design that Jerry G. <[email protected]>
wrote (in <[email protected]>) about 'The Dust Problem',


What really happens is that when you open their cage and clean it out,
you frighten the electrons, so that they are on their best behaviour of
a week or two.
--

That reminds me that electronics run on smoke . It doesnt work anymore once
you let the smoke out LOL
 
O

Orange

Jan 1, 1970
0
Interesting..
What would you reccomend for cleaning dust? I've got some compressed
air called "Blaster" but it contains some
tetrafluoro-dont-know-exactly. Label says that it can cause plastic to
"discolor", so I haven't used it at all.
Computer power supplies are sooo dusty. I've heard there are some
filters for dust. Can they be used on any PC or just some special
cases?
 
H

hemyd

Jan 1, 1970
0
Paul Burridge said:
Hi guys,

There have been many times IME that a piece of electronic equipmenet
has failed to function altogether or more likely developed some
annoying intermittent fault and the cure was simply to take the lid
off and blast the circuit board(s) with an aerosol of compressed air.
Dust must have been the problem. But why? It's hardly a great
electrical conductor after all.

p.

I have found that in most cases dust causes problems only when it gets
dislodged and jammed *into* things, such as sockets and connectors, or when
it gets wet. I have on many occasions found that attempts by people to clean
dust off electronic circuits often cause more problems than the dust itself.
Removing dust should be done as a planned service operation rather than
piecemeal. A socket or connector should definitely be dusted before
inserting a plug or card.

Henry
 
H

hemyd

Jan 1, 1970
0
Orange said:
Interesting..
What would you reccomend for cleaning dust? I've got some compressed
air called "Blaster" but it contains some
tetrafluoro-dont-know-exactly. Label says that it can cause plastic to
"discolor", so I haven't used it at all.
Computer power supplies are sooo dusty. I've heard there are some
filters for dust. Can they be used on any PC or just some special
cases?

Contrary to my previous comment, I do believe that cooling fans and
heatsinks should be dusted occsionally.

Henry.
 
P

Paul Burridge

Jan 1, 1970
0
Interesting..
What would you reccomend for cleaning dust? I've got some compressed
air called "Blaster" but it contains some
tetrafluoro-dont-know-exactly. Label says that it can cause plastic to
"discolor", so I haven't used it at all.

Discolouration's one thing; static's another altogether. I'm just
wondering if anyone's actually blown a chip (or chips) by dusting them
off with an aerosol? I only ask because on occasions where I've used a
C02 fire extinguisher, it's caused a large build-up of static on me
that was discharged with a huge spark the next time I approached
something earthed. If there are any additives in the compressed air
sprays that could give rise to the same effect, then it'd be wise to
avoid them around CMOS circuitry!
 
R

Roy McCammon

Jan 1, 1970
0
Paul said:
Hi guys,

There have been many times IME that a piece of electronic equipmenet
has failed to function altogether or more likely developed some
annoying intermittent fault and the cure was simply to take the lid
off and blast the circuit board(s) with an aerosol of compressed air.
Dust must have been the problem. But why? It's hardly a great
electrical conductor after all.

I took over an Antarctic satellite tracking station some
years ago. The previous manager said that every so often
things would quit working and he had to take out the circuit
cards and dust them off. (McMurdo has plenty of ground
volcanic dust). I said OK, thanks for the tip. Sure
enough, about once every 6-12 weeks things would stop
working. But instead of taking the cards out and dusting
them off (very high static electricity area), I just cycled
the power and it would work again for 6-12 weeks.

By the way, one day I was foolish enough to separate
two wool blankets and while holding one, I threw the
other onto a metal bed frame. After about one second,
a three foot long arc snapped out from the bed frame
and hit me in the ankle. And it hurt!
 
L

LASERandDVDfan

Jan 1, 1970
0
Discolouration's one thing; static's another altogether. I'm just
wondering if anyone's actually blown a chip (or chips) by dusting them
off with an aerosol?

No. But I make sure to use a can of compressed air from a known brand with a
guarantee that they won't harm anything.

I would recommend Belkin and Fellowes aerosol dusters out of anything else
except buying a high pressure electric air compressor. - Reinhart
 
J

John Woodgate

Jan 1, 1970
0
I read in sci.electronics.design that Roy McCammon <[email protected]>
wrote (in said:
By the way, one day I was foolish enough to separate
two wool blankets and while holding one, I threw the
other onto a metal bed frame. After about one second,
a three foot long arc snapped out from the bed frame
and hit me in the ankle. And it hurt!

We must immediately write a standard for ESD requirements for
Antarctica. Air discharge testing at 500 kV sounds about right, based on
your field report.

You re-invented the electrophorus, of course.
 
R

Roy McCammon

Jan 1, 1970
0
John said:
I read in sci.electronics.design that Roy McCammon <[email protected]>



We must immediately write a standard for ESD requirements for
Antarctica. Air discharge testing at 500 kV sounds about right, based on
your field report.
shhhhh


You re-invented the electrophorus, of course.

Does it hurt?
 
J

JW

Jan 1, 1970
0
That reminds me that electronics run on smoke . It doesnt work anymore once
you let the smoke out LOL

And everyone knows that semiconductors smoke and blow out to protect the
fuse!
 
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