PC plugged in during maintenance?

[BigDaddyJ]

Hey guys I decided to get some tools and a couple of books and tear into a PC or two. However, in my reading I have found a contradiction and would like your advice. I have always thought that the power should be off and the pc unplugged during ANY maintenance. I recently read an article that stated the following
"Leave a computer plugged in when working on it. (unless its the power supply you are working on). The ground pin in the wall plug is an excellent ground and this ensures you are properly grounded when your wrist strap is connected to the computer's case."
I really dont want to get fried, so If those of you that do this on a regular basis would please advise. Thanks in advance

[YODA74]

Thats kind of a personal judgement. I have been known to play with 220 and 440 without shuting it down, but would not recommend this procedure.When working with any electricity Please disconnect all power.It's not the voltage that gets you, you can have a million volts go thru your body and nothing but just let 1/100th of an amp with that voltage show up and you are crispy critters.Unless you have taken electricity 1-2-3 and are a certified electricion or have worked as a lineman heed this warning. http://www.PCGuide.com/ubb/eek.gif

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Treading,Troden,Trails
HERE (http://www.davematthewsband.com)

[Rick]

Prior to the ATX you could leave the power supply plugged in and not do hard to the circuit boards.
That however has changed .
The AT power supply when turned off did not provide power to the mother board or any of the other devices
The ATX supplies power to the Mother at all times.
Working on the system while it is plugged in can cause damage to many of the system components and You.
In Fact it’s also a good Idea to unplug the system .
Then Press the power button.
You will note that some power is still stored in the capacitors on the mother board .
The power , drive , and other Led’s will lite up for a moment.

By pressing the power button you drain all the remaining power.

To avoid doing damage .
Work on a well grounded work area.
That is Not connected to the system power supply.
A Grounded work bench works best

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To ERR is HUMAN
To REALLY screw things UP, YOU NEED a COMPUTER !

[Whyzman]

Seems like two potential "toast" candidates if you leave the unit plugged in: Operator & Board.

I wouldn't have left plugged in even prior to the ATX...too many things to potentially go wrong. The only advantage would be the ground it supplies while working. The disadvantage would be what a price to pay for the potential 6' under ground! The computer can be replaced...you cannot! http://www.PCGuide.com/ubb/wink.gif

If you're serious about "messin" under the hood, I would invest in a grounding wrist strap. Should be able to get those from Radio Shack I would guess...or your local computer supply shop.

The folks who probably recommended it would be Okay to leave plugged in probably have a Viatical business! http://www.PCGuide.com/ubb/biggrin.gif

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May all your dealings in life be win/win!

Whyzman

[This message has been edited by Whyzman (edited 11-28-2001).]

[BigDaddyJ]

Thanks for the responses gang. That is the response I expected. I do have the wrist strap, so, I just clip it to the chassis of the pc and touch something or someone to discharge any built up static?

[Rick]

If you connect the strap to the PC case you are gounded to the case.
and should be safe to work on it.


------------------
To ERR is HUMAN
To REALLY screw things UP, YOU NEED a COMPUTER !

[Paleo Pete]

I do have the wrist strap, so, I just clip it to the chassis of the pc and touch something or someone to discharge any built up static?

Yes, but unplug it AFTER you touch the case. After you unplug it you're no longer grounded. Don't try to discharge static electricity by touching someone else....giving them or you a shock is a possibility and that's not fun. It takes 2000 volts for you to feel it...100 volts to damage components. 2000 volts is no fun at all.

Clip on the ground strap, touch the chassis, then unplug the machine. You should then be free of ESD. If you unplug it first it has no ground to discharge to, which does not achieve the intended objective...

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[bassman]

Here is a tip,
Go to the hardware store, buy a length of copper wire(bare if they have it, if not, strip the insulation), attach it to the underside of your workbench, attach the other end to a positive ground source,(mine goes thru the wall and attches to a 4' ground rod).
You can use this to discharge yourself, run a ground strap from it to case,...
10' of 12 guage bare copper should run around $2.00 to $3.00

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[mjc]

Another method it to use a powerstrip (one with a light that is on when powered) and plug the machine into it and then kill the switch on the strip...keeping the strip plugged in...works great when you can't bring the machine to a bench setup like bassman was talking about.

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mjc
Links list:Computer Links (http://www.dreamwater.org/tech/mjc/index.htm)

Celts are the men that heaven made mad, For all their battles are merry and their songs are all sad.

[rond36]

Something that I have done because I live in an older house without grounded outlets I ran a #12 copper wire from my PC chassis outside to the cable TV ground rod and leave it hooked up all the time serge suppresors don't work well when thay are not grounded atleast that is what the inst. said when I bought it. So I just hook my wrist strap to the chassis unplug the PC no power and it is still grounded. It also grounds the rest of the outlet strips when the PC is pluged in. Also the switch on the back of the PSU will do the same thing as MJC suggested (if I had a grounded outlet)

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Alright who messed it up this time!

[This message has been edited by rond36 (edited 11-29-2001).]

[iropnman]

Originally posted by BigDaddyJ:
Hey guys I decided to get some tools and a couple of books and tear into a PC or two. However, in my reading I have found a contradiction and would like your advice. I have always thought that the power should be off and the pc unplugged during ANY maintenance. I recently read an article that stated the following
"Leave a computer plugged in when working on it. (unless its the power supply you are working on). The ground pin in the wall plug is an excellent ground and this ensures you are properly grounded when your wrist strap is connected to the computer's case."
I really dont want to get fried, so If those of you that do this on a regular basis would please advise. Thanks in advance

YES IF YOU DO NOT HAVE YOUR GROUND STRAP HOOKED UP TO A GROUNDROD LIKE I DO YOU SHOULD LEAVE THE COMPUTER PLUGGED IN BECAUSE THEY ARE RIGHT THE THE BEST GROUND OTHER WISE IS THROUGH YOUR ELECTRICAL BOX BUT YOU CAN GO OUT AND RUN A WIRE FROM THERE GROUND ROD AND THEN YOU CAN HOOK UP TO IT AND NEVER HAVE TO LEAVE A COMPUTER PLUGGED UP AGAIN . HOPE THIS WILL HELP IRONMAN

[Jericho]

This isnt a particularly productive reply, but just wanted to thank those who have contributed to this as I, too, will be opening up my computer for the first time very soon and attempting to add a memory chip or two. When I mention to a few friends the precautions I'm taking to avoid static disaster, they kinda laugh it off, saying they just discharge their static by touching the chasis and then go to work without any anti-static protection. I always fear the worse, so I'll be cautious. Keep this thread alive, I'd love to hear more input.

[kenja]

A variation of mjc's reply: Some ATX supplies have an on/off rocker switch. I can leave the case plugged into the wall (surge protector, actually) for good grounding and not fear the +5VSB voltage messing up the components I'm installing/uninstalling.

[iisbob]

Not sure where this iron dude get's his mis-information-but please DON'T post anymore of it!! You'll get someone killed!!

ALWAYS unplugg your PC while working on it! Not just for your protection, but also for the protection of the delicate electronic components inside-as Pete noted, ground your self, then unplug the case-you don't have to wear an ESD strap-but it doesn't hurt ( i've never used one, i always touch the case and unplug it however before doing any kinda work inside it!).


This other fine fellows with their ground bench advice are worth following too, and you can get yourself a rubber mat to help insulate your workbench-i use one myself.

It takes less than 100 volts to damage the electronic components in a PC, and when you pass on ESD-you're in the 2-3000 volt range! that little " ping " you feel when someone shocks you is enough to fry any component in your PC case! So be careful!




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iisbob

Life of a tech-support specialist-
"..Tech Support: "Use the right button to click on the shortcut--"
Customer: "I don't have a right button."
Tech Support: "You should have a right button."
Customer: "I'm sure. I have 'ctrl', 'alt', 'backspace'..."

[This message has been edited by iisbob (edited 01-01-2002).]

[rond36]

Most newer motherboards have an LED on the board and as long as this LED is lit it is not safe to work on your PC because the 3.3V+ standby power is still active in the DIMM slots . Inserting or removing DIMMs while this light is on can damage the motherboard, or DIMM or both DIMM and board! Also other parts of the motherboard are still powered up I know this because the LED in my optical mouse doesn't go out when the PC is turned off so the PS2 ports also have power and the PS2 ports use 5V+ it must be active in the board. I also have a Quantum HDD that has an LED on the PCB indicating power to the hard drive controller (5V+) that doesn't go out when the PC is turned off. These voltages aren't enough to hurt you but can damage components! For the 3.3V+ and 5V+ to be active on the motherboard the 120V AC is still active in the PSU and it will give you real good shock!!! Always unplug the PC or at least turn off the power strip or serge suppressor when working inside your PC for safety and to prevent damage to components.

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I think Windows XP and Microsoft use more of my bandwidth than I do!

[kenja]

Thanks for the reminder, Rond36. The +3.3V will be there on motherboards with the STR (Suspend To RAM) option.

[Hardtek1976]

Hey guys,
Like I said I'll drop in when I can
For those of you who live in a house with older two conductor wiring this can help. Recently I was watching one of our local home improvement shows(Jon Eakes) and it was discussing older two conductor house wiring. According to Ontario hydro regulations an electrician can not replace a two pronged outlet with a standard three prong outlet. It will give a false impression of safety (no ground),is dangerous and illegal. He must replace the entire wire (3 conductor) back to the control panel if he chooses a standard 3 pin outlet. However, he also has another option that if he keeps the original two conductor wire he must replace the outlet with a 3 pin GFI (grond fault interruption) outlet. The ground (third pin) becomes effective in such a situation. Don't ask me why, I'm not familiar with the GFI outlets. Also check with your local bylaws department as this can vary from province to province or state to state and even locally.

As to iropnman, please as iisbob has said be carefull as to what information is posted, especially with requards to what you said, it could be dangerous. There are EXPERTS in their own fields who visit this forum and they normally check their egos at the door, mine has just been unchecked. I am a fully qualified electronic technologist, just do a search of this forum for my posts and you'll find out exactly who I am. Don't laugh it is just what I chose to do,I'M FULLY CERTIFIED. When working on any electronic equipment (component replacement) it is best to unplug it taking into consideration electrostatic discharge as some of the good folks have discussed.

Just had to have my Lonnie's worth, also known as a Canadian dollar
http://www.PCGuide.com/ubb/biggrin.gif
__________________________

Ron

[This message has been edited by Hardtek1976 (edited 01-03-2002).]

[This message has been edited by Hardtek1976 (edited 01-03-2002).]

[like2be]

"strap on the ESD wristband,unplug,switch-off and don't forget to NOT rub your bare or stocking feet excessively under the bench or desk as this will GENERATE a current through your body. Right? http://www.PCGuide.com/ubb/tongue.gif

[YODA74]

Hardtek1976,

A ground fault condition occurs when a person using an electrical appliance comes into unintentional contact with an exposed high voltage wire. If that individual also makes contact with a grounded object, the result is a ground fault that could lead to electrocution. A GFCI device detects the presence of this condition and interrupts the electrical current. A GFCI works by monitoring the current flow through electrical products and wiring. In the U.S., the prevalent wiring in the home is 115 volts single phase, consisting of two current carrying conductors -- an ungrounded "hot" wire and a grounded "neutral" wire -- and a third "ground" wire which does not conduct current during normal operation. When the system operates safely, the current flowing through the hot wire going to an appliance is equal to the current coming back through the neutral wire and no current flows through the ground wire.
Or something like that.
http://www.PCGuide.com/ubb/biggrin.gif

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Treading,Troden,Trails
HERE (http://www.davematthewsband.com)

[Hardtek1976]

YODA74,

Got it and thanks :cool

_______________________

Ron