The little 'puter that could...

[WarLocke]

Last Friday my computer decided to die. For no apparent reason, in the middle of the morning. One minute I'm tapping away at the keyboard, and the next -- nothing. Blank screen.

So I fiddle with the power swich and button. Nothing. Nada. Not a peep, click, or whir of fans powering up. This can't be good.

So I'm thinking I blew my power supply somehow, since I get no response whatsoever when trying to power it on; If the problem was something else like the mobo, I'd at least be seeing the power supply's fan turning. So now I need to hike down to the only computer shop in town and hope they stock power supplies (I don't see why not, but I've yet to enter the store, and with my luck they won't). I don't have a CC or PayPal account, so online ordering is out of the question.

This morning, I decided to open the case up (had been meaning to for awhile, but this past week was one of those "surprise every minute" ones) and see if it was, maybe, just a loose connection somewhere. Hey, I could hope.

Oh holy jeebus, the horror...

Dust... everywhere. Ugh. I have no idea how all that dust got into my little comp's innards, but there it was. The power supplie's air intake (I guess they're intakes, anyway) slots were caked with it, and there were unhealthy-looking amounts around the CPU fan and the video card. Ugh.

I wiped away what I could readily get to with some paper towels/napkins, although there's still alot in various nooks and crannies. I can't do much else with what I have available at home. I suppose I'll check in the computer shoppe for those cans of compressed air; those seem to always get mentioned in relation to cleaning out a computer's innards.

So... yeah. I (hopefully, only) need a new power supply (probably meatier than the 300 watt one I had, if I blew the original) for which I have no idea what I'll have to shell out ($40? $60?), I also really need to de-dustify my computer (which doesn't seem to have been noticeably effected by the buildup, but still, nipping it in the {belated} bud can't hurt). Until then, I'm on these crappy no-games no-downloads library computers.

Yeah, my life sucks. :blink:

- WL

[pakman]

Suckage. You should seet he amount of dust my computer collectes from being at Purdue. Since there are no air filters in the dorms, all the dust from the heaters is in the hall and gets everywhere inside the case. The dust settles like mad. Say I put my calculator on my desk for about ten minutes while I am not using it. When I pick it up again, I have to wipe the screen with my shirt. That's how bad the dust is.

As for cleaning....just go to the hardware store, the cans of air will be much cheaper.

[--Pete]

Hi,

I suppose I'll check in the computer shoppe for those cans of compressed air; those seem to always get mentioned in relation to cleaning out a computer's innards.

NO!!!! Blowing dust around your computer innards is not a good idea. The dust which is sitting on top of things like connectors, fans, switches, etc. will be blown *into* those same items causing a problem which will be an order of magnitude worse. Most dust does no damage to computers unless it is in such thick quantities that it is acting as insulation. That is not typically a problem unless one has pets.

I wiped away what I could readily get to with some paper towels/napkins, although there's still alot in various nooks and crannies.

Bad idea. Paper is an insulator and as such can build up a static charge. Uncontrolled static charges kill hundreds of times as many computer components as dust ever will. Never wipe down any internal component of your computer with cloth or paper. Indeed, never wipe them down at all. Pick off the big chunks of dust with your fingers, making sure that you are wearing a grounding strap connected to the case.

If you absolutely must clean the inside of your computer, use a vacuum cleaner. Take the crevice tool, wrap aluminum foil around it and extending back about a quarter of an inch into the opening. Form a "lug" by twisting some of the foil. Connect one end of a grounding strap to that lug, the other end to the computer chassis and suck that dust out. If you plan to do a lot of this, buy or make a metal nozzle for your vacuum and permanently attach a grounding strap with a screw.

Do yourself a favor and don't make a bad situation worse.

--Pete

[Guest]

And make sure you follow the part about grounding the vacuum nozzle. Even if you think you are keeping a safe distance between the the nozzkle and the board - you arent. Depending on conditions a static charge will travel through thick dust.

[channel1]

buy or make a metal nozzle for your vacuum and permanently attach a grounding strap with a screw.

BAD advice. Not a bad idea, if you are always careful about never working on any powered circuit, but really bad advice to give. Too many people aren't careful. There was a local kid managed to kill himself last year, cleaning out his power supply. It happened that the live and neutral wires were crossed in it from the manufacturer, even though it was turned off, it was still hot.

Also, if you are going to putz around inside your 'puter with a grounded instrument, remember you also have at least one battery on the motherboard supplying power for the BIOS settings and clock.

If you aren't sure about what you are doing, buy a STATIC DISCHARGE (NOT Grounding) clip. It will have a resistor in it that will prevent a high current discharge that can create a spark, or worse. If you DO know what you're doing, you can make your own.

By the way, after 30 years of working in electronics, I can just about count the number of cases of static damage I've had on one finger. Common sense goes a long way, too bad it's so rare.

As for cleaning scunge out of a 'puter, here's what I do:

1: REMOVE anything that can reasonably be taken out of the machine, i.e. power supply, heatsinks / fans. Take them outside, preferably, and brush them out with a non-conductive, anti-static brush where the dust won't just float around in the room with the 'puter.

2: Inside what's left of the puter, use the brush to dislodge dust while having a vacuum close enough to catch it.

3: Canned air if necessary to move hard to reach dust, with the vacuum still going to catch it. Watch out what you use for compressed air. A competitor of mine managed to blow every 'puter in an office, when they used the air hose that was available in that location. Steel tank, brass nozzle, zap! :) Of course, they did all the machines, without bothering to see if they still worked after the treatment. Just because they charge $95 / hour doesn't mean they know what they're doing.

Common sense: take note of what you're wearing, wool sweaters aren't a good idea. Humid days can be good, although air conditioning defeats that advantage.

Heat is a killer, especially long term. Most dust acts as an insulator, as well as blocking the free flow of air. As a general rule with electronics, the hotter it runs, the shorter it's life.

Last word: I see a lot of people who put the 'puter on the floor. Although it's out of the way, it is the worse place for picking up dust. Dust will eventually settle to the floor, and walking around will stir it up just enough for the intake on the 'puter to pick it up.

-rcv-

[--Pete]

Hi,

Not a bad idea, if you are always careful about never working on any powered circuit, but really bad advice to give. Too many people aren't careful. There was a local kid managed to kill himself last year, cleaning out his power supply. It happened that the live and neutral wires were crossed in it from the manufacturer, even though it was turned off, it was still hot.

Also, if you are going to putz around inside your 'puter with a grounded instrument, remember you also have at least one battery on the motherboard supplying power for the BIOS settings and clock.


I agree that care must be taken when working around electrical devices. I don't consider that a major consideration in reference to personal computers. A few points:
1) One should always disconnect any appliance from the mains before doing any work. If troubleshooting and power is needed, then extreme caution should be used.
2) With the exception of inside the power supply, the voltages in a computer are not harmful (±12V and ±5V DC). The power supply must be removed from the case to be opened and that is almost impossible to do without removing the power cord. Now, some old computers do have a 120VAC switch that is exposed, but even that has disappeared from newer computers. The possibility of harming oneself working on a computer is very small.
3) Most BIOS batteries are the little disk types. Since circuit boards are mostly silk screened and varnished, it requires quite a bit of effort to short out that battery, and even if it happens, it is a small matter to replace it.

By the way, after 30 years of working in electronics, I can just about count the number of cases of static damage I've had on one finger. Common sense goes a long way, too bad it's so rare.

I don't want to cast aspersions on your abilities, but I will ask how you know you've only had one. Most electrostatic damage doesn't fry the component immediately. The damage is a lot more subtle and insidious than that. Which is why places where the damage can have dangerous consequences (such as aerospace and military) take what might seem to be extreme precautions. For more on this do a Google search on "electrostatic damage electronics" and you will learn that a lot more damage is caused than many experienced workers in the field realize and that most of the damage is not detected until much after it is caused. I spent seven years intentionally destroying electronics to qualify them for space applications. Much of what crossed our labs, even though it was new, had been ESDed before we got it. Only microscopic examination would reveal it.

A competitor of mine managed to blow every 'puter in an office, when they used the air hose that was available in that location. Steel tank, brass nozzle, zap! :)

Shop air is never a good idea for cleaning anyway. The oil in most shop air will leave a film on the boards that will combine with dust to form something not unlike cement. Cleaning that mess is almost impossible. Filtered, dry, shop air doesn't have that problem, but unless the air is mainly used for spray painting, it is rarely clean. And, of course, the static problem is very large with moving air -- however, a grounding strap will solve that problem, too (with or without a meg or so in-line).

--Pete

[Guest]

Vacuums are static electicity generators on a dry day.

I work as a control electician, and I never worry about it when I work. I have yet to burn a board with static electricity. Im not saying it couldnt happen, but your right its rare. Of course wearing a sweater or working on a rug would also greatly increase your odds of an accident.

[channel1]

You missed my main point, Pete. I guess I had it buried.

Use a Static Dissipation strap, NOT a Ground Strap when working on electrical equipment!

Being grounded gets people killed. You can buy a static dissipation cable for under $10, or make one for under a buck.

I don't want to cast aspersions on your abilities, but I will ask how you know you've only had one.

Okay, only one that was instantly obvious. It was while using a grounded-element soldering station, by the way. :) It's not the static that kills a circuit, it the static DISCHARGE. A static dissipation cable typically has a 300k-3m Ohm resistance to ground, which allows the static charge to dissipate slowly. A low resistance connection to ground is where the spark comes from.

Which is why places where the damage can have dangerous consequences (such as aerospace and military) take what might seem to be extreme precautions.

Heh. My original training in electronics was as an Avionics Technician. Graduated 1976, only worked in it for less than a year- no money in it for the pressure. You are right, we took extensive training on how to work on static sensitive devices, I still have the textbook for that. It is over an inch thick.

-rcv-

[Guest]

He said ground the vacuum nozzle. You are perfectly safe hold the grounded vacuum nozzle.

BTW: The static discharge that kills the computers comes from the person/vaccuum not the machines almost always - so a straight ground is fine in that respect.

[kandrathe]

In your case then, we shall make an exception. Please ground yourself at all times.

[Guest]

Thats nice.

Im guessing you dont even understand what were talking about.

[kandrathe]

Gads. No, I'm implying that you are being a dense twit. More than one person schooled and skilled in working with electricity cautions about using a "Grounding" wire, and you choose to post to the contrary. You can ground the nozzle to the vaccum, but you will not remove the possibility of static discharge coming from you. The person using the vaccum, still needs to be wearing a "Static dissipation" strap, and not a grounding strap.

So, if you choose to ground yourself contrary to these warnings, then I'd say, let Darwin choose.

[Guest]

Based on your response I can see that you didnt actually read all the other posts.


No one ever said that it was safe to work on a plugged in computer with a grounding strap on.

In fact, in defending Petes statment all I said is that it wouldnt kill you. Which is completely accurate. Putting a disapation strap on the vacuum instead of a ground would make no sense.

[--Pete]

Hi,

In my original post, I said, "making sure that you are wearing a grounding strap connected to the case." and, "Connect one end of a grounding strap to that lug, the other end to the computer".

Now, I was using the term "grounding strap" in two different senses here. In the first case, I meant the standard anti-static wrist strap and wire with clip that can be purchased at any electronics store. This typically has an in-line resistance of a few hundred kilohm to a few megohms. This "strap" is what is used to ground the *person* to the case and the in-line resistance is a necessary safety feature. If one is going to distinguish between a "grounding strap" and a "static discharge clip", then it is in this case that I should have been corrected but wasn't. My feeble defense is that we always just called these devices "grounding straps".

The second sense in which I used the phrase "grounding strap", I meant just a wire with clips at each end. One clip on the vacuum nozzle, the other to the computer chassis. No additional resistance. This was the use that I was challenged on and I defended it in my reply. If I was at all at fault, it was for failing to stress that power should be off *and unplugged* when using this device (or, indeed, whenever working inside the computer except for troubleshooting). However, as I replied before, this is not a dangerous condition. Indeed, it is exactly the condition that occurs whenever using any electrical device that is grounded by a third wire. If something does occur, the electricity follows the path through the ground (which is very low resistance) instead of through the person (which is a much higher resistance). Furthermore, in dry air conditions, the airflow through an insulating nozzle can generate a *lot* of static charge, enough that the potential across a megger can build up to a few tens of volts -- more than enough to kill many MOS circuits. So, my advice stands as written and for what I consider valid reasons.

--Pete

[kandrathe]

Based on your response I can see that you didnt actually read all the other posts.

Are you trolling?

No one ever said that it was safe to work on a plugged in computer with a grounding strap on.

I guess you are. That is not what I said either.

[Occhidiangela]

Pig enjoys it, since you get all muddy, at which point you are both "grounded." :D

[Guest]

1. In the post I originally responded to Channel1 specifically claimed it was unsafe to put a ground on the vaccum nozzle(contridicting what both Pete and I said be fore).

Channel was completely wrong here. Its unsafe to ground your self, but it is safe to ground the nozzel.

2 I corrected him.

3 YOU SUGGEST I DO SOMETHING I NEVER EVEN MENTIONED(ground the person) IN HOPES THAT I KILL MY SELF.

4 I point out that I was talking about the vacuum.(the pertainent fact that you still have not understood).

5 You now admit I am right about the vaccum, but start going on about personal grounding straps. (you appearently didnt read that I was adressing a post specifically about the vaccum)

And you post includes this line - "So, if you choose to ground yourself contrary to these warnings, then I'd say, let Darwin choose." "

6 My response inclues this line - "No one ever said that it was safe to work on a plugged in computer with a grounding strap on. "

7 Which brings us to your last post.
"QUOTE
No one ever said that it was safe to work on a plugged in computer with a grounding strap on.

I guess you are. That is not what I said either. "




I really dont know why you even got in this thread and started flaming. I condridicted Channel 1 on a specific thing, because I had already support the exact idea he was shooting down.

So what do you do - you come in and suggest I kill my self.

The you have the nerve to call me "troll". Think about it. Who is trolling.

[channel1]

Ghostiger: In the post I originally responded to Channel1 specifically claimed it was unsafe to put a ground on the vaccum nozzle(contridicting what both Pete and I said be fore).

Channel was completely wrong here. Its unsafe to ground your self, but it is safe to ground the nozzel.

Okay, it is also "safe" to stand under a piano suspended by a crane.
But, accidents happen. That is why it's not a good idea to work with instruments that provide a path to complete a no-resistance electrical circuit. With one hand on your metal vacuum nozzle, all it takes is to touch something with an electrical potential with the other hand to complete a circuit through yourself. Something silly, like the plug on the vacuum, can do it.

Some years ago, I paid big bucks for a vacuum designed for cleaning out laser printers. Everything on it, case, hose and nozzles, are a fashionable black plastic, impregnated with carbon fibers. They do that so it will dissipate charge without creating a situation where you get zapped.

It's none of my business if you want to work in a potentially unsafe situation. Telling other people to do it is irresponsible.

-rcv-

[Guest]

I guess its a different perspective. You are going t drop that vaccum if you get shocked, so I would not be overly concerned.

I work everyday in electric panels. Often there are hot wires in in the panels. I would never strap my self into a ground and would never stand on a conductor but I consider holding or brushing against a ground an acceptable risk(Im talking about safety not about protceting the board right now).

BTW I wouldnt do this in a panel with 360 and I would be extra careful in a panel with 210.

[kandrathe]

Hose me off. I'm done.