On Thu, 24 May 2007 00:18:55 -0400, "Z" wrote:


Well, the problem seems to definitely be more widespread. I installed a USB
keyboard and it worked great on first boot. The both it and the mouse(PS/2)
stopped working. THEN, their parallel dongle(For their Alldata parts
software) stopped working. At that point I moved their shop database to
their other computer and shut the bad one down. I'm ordering a replacement
motherboard in the morning and will give the rest a thorough cleaning.

I had your post in mind when I went back to the shop this morning. I
watched several of their mechanics come in, grab an Alldata DVD(The package
contains a dozen or so DVD's each covering a range of auto makers/vehicle
types/years) and pop it into the computer. I actually saw the dust pop off
their hands onto the DVD's as they placed them in the computer, must be
static.

First I recommend that they not handle these DVDs. Rip them
to a hard drive as ISO and use an emulation program like
Daemon Tools to access these ISO stored on the system (or
store the ISOs on a central fileserver, we dont' know how
elaborate this setup is. They just should not be handling
and inserting media while covered in metallic dust, and they
would probably love that they no longer have to fool around
with popping in DVDs, though it will take a minor amount of
training for them to start using a shortcut already present
instead of loading the DVD each time.





If anyone has any suggestions on affordable 'industrial' PC cases/hardware
I'd like to hear them. I'm usually pretty good at finding thing on Google,
but all I've come across is hyper-expensive/rack mount blocks that really
don't fit their needs.

Well it won't be cheap... that's what happens when an
industrial, niche product. We don't know anything about
this scenario, like amount of space available for the case
or if they could move it or make more room for it or
anything like t hat. It's not like there's one page with
every industrial case on it, but they're out there... you
are the only one who knows what limitations there are as
industrial cases generally aren't just same size and shape
as they'd be if it were a case for Joe Average's Gaming
system.

If you want to keep them out of the DVD drive, a lockable 2
or 3U rack case might not be such a bad idea.

I did find one possible solution that I am pursuing. They gave me an 8"x6"
auto air filter. I bought a 4" 115v fan from Radio Shack and bought wood,
flexible gutter elbow and attachments at Home Depot(~$34 in parts).

Might I suggest that you increase the filter size (or use
two), use a DC fan instead of AC (safety concerns, remember
someone else may eventually fiddle with this or bump it or
who-knows-what and you might be liable for tack-on circuits
like this.

I suggest not using wood or gutter elbow and similar things.
Take a case which has the drive bay not attached to the
bottom 1/3rd of the front metal wall of the case. Cut a
hole in that metal to accomodate a 120mm x 38mm (not
25.4mm!) thick fan. The fan is mounted to the inside of
that metal wall.

Get some foam adhesive backed weatherstripping from the
hardware store. With it, create an airtight border around
the inside of the case bezel, that entire front panel.
Depending on how it's made and shaped you may need to vary
the application of the foam but basically just stick it on
such that it extends past the edge and is compressed
slightly when the bezel is placed back on the metal chassis.
Also take a piece of high density foam cut to shape and
liberally contact cement it toward the middle of the bezel
to form another pocket of trapped air right in front of the
fan. Finally, cut out a large rectangular hole in the
bottom front of the bezel. The dimensions of this hole will
be about 1" narrower and 1" shorter than the dimensions of
the filter material. The extra 1/2" overlap on each side is
so you can mount the filter. To mount it, get some aluminum
angle from a hardware store. Dimensions like 1/2" x 1/2"
and 1/8" thick should be about right but the specifics of
the application might make a different size more wieldy.

Measure and cut the channel into the sides and bottom of a
channel to hold the filter(s). The top is left open so the
filters can be slid in and out, or if the filter gaskets are
thick enough to hold them in place well against gravity, you
could leave the bottom off the frame instead of the top. So
this channeled frame bolts to the case bezel, with the
filters out in front where they can see when they get dirty
and replace them. Don't forget to put a fan grill on the
front of the 120mm fan.



I'm
going to build a fan/filter system that pumps through the filter and into
the back of the PC.

It might work but since most cases were designed to have air
intake in the front, and exhaust out the rear of the PSU, it
seems more likely this will create a short loop where the
heated PSU exhaust is slow to mix with the ambient air due
to location and a higher % is drawn back into the system.
It would require a higher airflow rate to achieve same
average system temp. On the other hand, getting everything
out of the front of the system and having it either sealed
or as an exhaust would reduce dirt/dust/etc buildup on the
filter, "Maybe" (hard to say without knowing the environment
and exact configurations possible within that environment.
It would certainly be pretty noisey to have a high level of
filtration and thin ductwork. You might move away from
axial fans and use a radial fan (like squirrel cage type, a
larger size as a lot of ducting and filtering will require
more than a little 4" fan unless it's spinning so fast it is
very loud.



Supposedly this will filter all incoming air and create
a 'positive air pressure' in the case so that all other holes in the case
push air and dust away from the computer.


yes that is the general idea, you just have to make sure the
intake fan actually does push more air than the existing
fans (usually chassis and PSU rear) are exhausting. In
other words, be sure to test the positive pressurization and
that it is enough, not just a slight pressurization as the
pressure level changes as the filter gets clogged with dust,
moving from more positive to less positive pressure in the
case, even going to negative pressure once the filter is
clogged enough.


I'll update next week and a few months out on the filter system. I think
they also need to keep some handiwipes right next to the main shop computer.
I've cleaned enough bottoms with those, hopefully they work as well on shop
dust



The other common option is that you put the system in a
cabinet. I mean airtight with an intake and exhaust port
wherever it's necessary and then that intake is filtered.
System is just as it always was, but cleaned out, and
protected behind the sealed and filtered cabinet. There are
quite a few industrial cases like this, but that's not a
hard thing to build youself out of plywood or thicker
plexiglass/polycarbonate/etc, so long as they don't need to
use the DVD drive anymore, and if they need be able to turn
system off/on, of course a remotely mounted switch on the
cabinet.

You might also look at what options there are to reduce
total heat levels in the system. Lower heat requires less
airflow, results in less actively drawn in dust.