Since I am from the old school of computing technology (where off is actually off, none of this soft-on/off crap) it surprised me when I was putting in some dimms into a friend's HP that the RAM slots were powered for some reason (no, it was not in sleep mode). I pushed on the dimm and suddenly saw a bright point of light and little puff of smoke. I yanked the dimm out, only to find that one of the gold traces on the dim got so hot it melted the epoxy (or whatever holds it onto the pcb) that held it on and soldered itself to the dimm slot on the pc. So I ended up using a twice as large dimm in the other slot.
Moral of the story is unplug the power cable (we all do that don't we). Nothing gets your heart going like electricity! Like the time I was putting in a gable fan in my attic and cut a live wire with my T-Cutter's. THAT was a bigger spark, and burnt a nice big hole in the cutters. At least I got to exchange them at Home Depot
ngoy (I'm still alive! Darwin ain't got nothin' on me!)
One leaves the computer plugged in for the ground. Unplugged, you won't get electrocuted, but the box won't be grounded either. You have to pick one, or find another way of grounding the box (which realy isn't that hard).
One leaves the computer plugged in for the ground. Unplugged, you won't get electrocuted, but the box won't be grounded either. You have to pick one, or find another way of grounding the box (which realy isn't that hard)
For that matter, if you're concerned about static zapping computer components, it's typically sufficient to make sure you are at the same potential as the computer by using a wrist strap connected to the chassis.
You are correct. I like to either lick the chassis and keep my tongue touching, or keep my nipple pressed against the chassis while I am installing/removing cards.
Well, maybe leave it plugged in if your power supply has a switch on the back, but I'm not sure that's wise for ATX. I've got a VP6 based system. That board has a power led mounted on it that stays lit for a few seconds even after unplugging the power supply. Presumably the leftover juice comes from PS capacitors. Anytime I muck around in the case I unplug and wait. I slacked off on this habit once, managed to bump a molex connector just right, and toasted the nice 20GB drive that held bootsector +/boot + some other stuff. You could leave your box plugged in, but there are better ways of avoiding static cling.
That's the one thing I like about when I occasionally work on old AT computers. The damn power supplies go ON and OFF when you want them to, none of this crap with the power button connected to the motherboard and holding it for 6 seconds to make it turn off.
Yeah, the new ATX specs have power going to the board as long as the cord is in the wall. I was from the AT crowd too, I had actually been taught that a power supply plugged into a grounded socket was a good thing to leave when working inside the computer.
Luckly my surprise with the new ATX stuff wasn't as bad, I just had a machine power up when inserting a video card. No damage done.
To keep this a bit more on topic too, most good power supplies have a hard switch (as opposed to the soft one that the ATX power button triggers) on the back that will keep all current out of the motherboard.
I used to leave the power supply plugged in to for that same reason on my ATX Abit board.
Then I dropped a screw onto the motherboard and the computer came to life! Scared the hell out of me I tell ya.
Rather than reaching for the screw and causing a short-circuit or fire destroying my brand new mb, i unplugged the machine and thanked God that my system was fine afterwards. whew...
I guess that experience is closest to working on a dead person in a morgue and have them move/come to life. hehe...
Easy solution. leave it plugged in, but switched off at the wall socket.
It's kinda hard to do that when wall outlets aren't switched. (Yeah, I know the Brits have switches on all of their outlets...but they're weird that way.:-) )
Hang on- you're telling me that having a socket live all of the time is wierd? I mean - how about un-pluggin something and watching the lovely blue arcs... Man.. My GF always tries to make me turn everything off by the wall socket before unplugging it - mostly I do- but sometimes I am lax....
-=-
I recently put together a computer with a EnerMax case/power supply and a SANYO Dragon Lite motherboard, and even with the hard-switch (on the back of the case) switched to off, their was a green led on the motherboard glowing. I had to unplug the powerstrip from the wall to get it totally off.
There is one compelling reason to leave the power-supply plugged in when working on the system -- static.
Most folks don't use ground straps, and hence may carry a potential with respect to devices they are handling. You need not see, or feel an arc for to destroy a component!
A good supply should have a rocker switch in the back that cuts the power, but leaves earth ground intact.
This way you can power off the system (for real), and it will remain grounded. Now all you need do is keep a hand on the case at all times. -- Matt
Thats nothing. One time I was hanging a shelf and had to drill a pilot hole for the bracket. Unfortunatly, I had forgotten that the breaker box was on the other side of the wall in the storage closet. Long story short I melted the the tip off a hardened drill bit and knocked out the power to my entire apartment complex.
It's easier/better to switch the PSU off at the PSU if it has a switch (no, not the front switch). Then switch the PC on with no a.c. power, this will discharge the caps in the psu - often the fans will spin slightly. I wouldn't necessarily believe that the case was grounded with a switched off ATX psu without checking - I haven't bothered to check th specks so I use a wrist strap. YMMV
Only great masters of style can succeed in being obtuse.
-- Oscar Wilde
Most UNIX programmers are great masters of style.
-- The Unnamed Usenetter
Re: (Score:4, Funny)
Re:Fireworks (Score:5, Funny)
Moral of the story is unplug the power cable (we all do that don't we). Nothing gets your heart going like electricity! Like the time I was putting in a gable fan in my attic and cut a live wire with my T-Cutter's. THAT was a bigger spark, and burnt a nice big hole in the cutters. At least I got to exchange them at Home Depot
ngoy
(I'm still alive! Darwin ain't got nothin' on me!)
Re:Fireworks (Score:1, Informative)
Re:Fireworks (Score:2, Insightful)
For that matter, if you're concerned about static zapping computer components, it's typically sufficient to make sure you are at the same potential as the computer by using a wrist strap connected to the chassis.
Re:Fireworks (Score:4, Funny)
Re:Fireworks (Score:1)
Re:Fireworks (Score:2)
Tim
Re:Fireworks (Score:5, Informative)
Luckly my surprise with the new ATX stuff wasn't as bad, I just had a machine power up when inserting a video card. No damage done.
To keep this a bit more on topic too, most good power supplies have a hard switch (as opposed to the soft one that the ATX power button triggers) on the back that will keep all current out of the motherboard.
Re:Fireworks (Score:2, Informative)
Then I dropped a screw onto the motherboard and the computer came to life! Scared the hell out of me I tell ya.
Rather than reaching for the screw and causing a short-circuit or fire destroying my brand new mb, i unplugged the machine and thanked God that my system was fine afterwards. whew...
I guess that experience is closest to working on a dead person in a morgue and have them move/come to life. hehe...
Re:Fireworks (Score:2)
screw this soft-off crap.
Re:Fireworks (Score:1)
Re:Fireworks (Score:2)
It's kinda hard to do that when wall outlets aren't switched. (Yeah, I know the Brits have switches on all of their outlets...but they're weird that way. :-) )
Re:Fireworks (Score:1)
Re:Fireworks (Score:1)
Re:Fireworks (Score:2, Informative)
Most folks don't use ground straps, and hence may carry a potential with respect to devices they are handling. You need not see, or feel an arc for to destroy a component!
A good supply should have a rocker switch in the back that cuts the power, but leaves earth ground intact.
This way you can power off the system (for real), and it will remain grounded. Now all you need do is keep a hand on the case at all times.
--
Matt
Re:Fireworks (Score:1, Funny)
earthing cables get you women (Score:2, Funny)
live and neutral are of course plastic, but the earth is a regular pin
That sinlge earthing cable landed me my wife, since she thought I was such a crazy ass to wire myself to the electrics to fix her computer.
Lesson be learned - save hardware, get a woman.Re:earthing cables get you women (Score:1)
Re:Fireworks (Score:2)
I wouldn't necessarily believe that the case was grounded with a switched off ATX psu without checking - I haven't bothered to check th specks so I use a wrist strap. YMMV