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Home > Archive > alt.certification.a-plus > September 2003 > some a+ questions
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| Michael Hoffman 2003-09-10, 9:26 pm |
| Been reading different texts, taking different sample tests.. here are a few
typical questions that I seem to get contradicting answers on.
I've read that an ATX power supply is always on.. isn't it non-sensical to
work on it when it is plugged into the outlet? At the same time, will the A+
expect me to say that you should connect your ground strap to the computer?
I think I've seen straps that connect directly to the ground of a grounded
outlet. This wouldn't seem to accomplish anything if the computer itself
isn't grounded.
"When performing any work on the internal components of a computer, a
technician should connect a wrist strap to the case of the computer for ESD
grounding. In general, computer components will function at 5V DC and 12V
DC. The only precaution that should be taken is that the power supply (with
a higher AC voltage) may store charge even when powered down"
I read something that said alcohol should be used to clean keyboards, since
water can cause problems. Yet the AIO book says alcohol can remove the print
off of keyboards .. which one would the A+ lean towards?
I've also encountered a question that implied that a laser printer's output
is the highest resolution for all printers. Unless I'm mistaken laser
printer's resolution is limited, is it not, to something like 800x600
because of the mechanics involved? Wouldn't an inkjet be capable of giving
an higher resolution, if not a better picture?
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| Adam Ross 2003-09-11, 1:24 am |
| First off, you are not supposed to technically work on the power supply,
except for maybe testing voltages along the red and black wires.
And oh, either way is correct for your ground strap. Thats not gonna be a
test question. However, I do believe hardwood floors are better for
grounding if that gives you a hint.
I wouldnt trust carpet for grounding.
"Michael Hoffman" <nospam@puleeze.com> wrote in message
news:3f5fc9c6$0$149$a1866201@n
ewsreader.visi.com...
> Been reading different texts, taking different sample tests.. here are a
few
> typical questions that I seem to get contradicting answers on.
>
> I've read that an ATX power supply is always on.. isn't it non-sensical to
> work on it when it is plugged into the outlet? At the same time, will the
A+
> expect me to say that you should connect your ground strap to the
computer?
> I think I've seen straps that connect directly to the ground of a grounded
> outlet. This wouldn't seem to accomplish anything if the computer itself
> isn't grounded.
>
>
> "When performing any work on the internal components of a computer, a
> technician should connect a wrist strap to the case of the computer for
ESD
> grounding. In general, computer components will function at 5V DC and 12V
> DC. The only precaution that should be taken is that the power supply
(with
> a higher AC voltage) may store charge even when powered down"
>
> I read something that said alcohol should be used to clean keyboards,
since
> water can cause problems. Yet the AIO book says alcohol can remove the
print
> off of keyboards .. which one would the A+ lean towards?
>
> I've also encountered a question that implied that a laser printer's
output
> is the highest resolution for all printers. Unless I'm mistaken laser
> printer's resolution is limited, is it not, to something like 800x600
> because of the mechanics involved? Wouldn't an inkjet be capable of giving
> an higher resolution, if not a better picture?
>
>
>
>
| |
|
| Always disconnect from the power outlet. Besides being the way Comptia likes
you to think, it is also a Health and Safety issue in many countries.
Whether you use a wrist strap is your perogative, however many companies
demand their use and to be perfectly honest if a client can see me I make
sure I am using one. The major point to remember is that you are NOT
earthing yourself or the machine - what you are in fact doing is balancing
your voltage level with the machines level - The thing to remember is that
even the earth has an electrical current running through it.
Cleaning keyboards - yup I have seen a few with no letters due to being
cleaned with alcohol. I usually wash them with a mild detergent, blow the
excess water off with compressed air and then put them in the sun for a few
hours (or the hot water closet overnight) never had a problem yet.
Printer resolution - 800 x 600? Irrelvant!!! Talk DPI - The default for
many printers is 150 DPI and many go to 300 or even 600 DPI, where a lazer
printer will usually run as 1200 to 2400 depending on the model and some top
line ones go even higher.
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| Karl S. 2003-09-11, 2:25 am |
| On Wed, 10 Sep 2003 20:06:20 +0000, Michael Hoffman wrote:
> Been reading different texts, taking different sample tests.. here are a
> few typical questions that I seem to get contradicting answers on.
>
> I've read that an ATX power supply is always on.. isn't it non-sensical to
> work on it when it is plugged into the outlet? At the same time, will the
> A+ expect me to say that you should connect your ground strap to the
> computer? I think I've seen straps that connect directly to the ground of
> a grounded outlet. This wouldn't seem to accomplish anything if the
> computer itself isn't grounded.
>
>
> "When performing any work on the internal components of a computer, a
> technician should connect a wrist strap to the case of the computer for
> ESD grounding. In general, computer components will function at 5V DC and
> 12V DC. The only precaution that should be taken is that the power supply
> (with a higher AC voltage) may store charge even when powered down"
>
The grounding strap connects you to the computer chassis so there will be
no difference in voltage between you and it. You could both be completely
isolated from "earth" ground or not, as long as there is no possibility of an
electro-static discharge into the circuitry from your body when you
touch it. Thus, you are "grounded" to the chassis even if the chassis is
not connected to an "earth" ground.
> I read something that said alcohol should be used to clean keyboards,
> since water can cause problems. Yet the AIO book says alcohol can remove
> the print off of keyboards .. which one would the A+ lean towards?
>
I believe the "book answer" would be distilled water, which does not
conduct electricity. One can only imagine how long that pure,
non-conductive distilled water stays pure upon entering a keyboard
however. My personal method is to disassemble the keyboard, clean the
non-electrical parts in a sink full of hot soapy water, and clean the
electrical parts with 99% isopropyl alcohol. For light touch-up cleaning,
I use mild soap-and-water in a nearly-dry paint brush, followed by a
completely dry paint brush to remove the loosened dirt. Your milage may
vary.
> I've also encountered a question that implied that a laser printer's
> output is the highest resolution for all printers. Unless I'm mistaken
> laser printer's resolution is limited, is it not, to something like
> 800x600 because of the mechanics involved? Wouldn't an inkjet be capable
> of giving an higher resolution, if not a better picture?
Look at a printout from a laser printer, then that from an inkjet. Laser
wins every time. If a laser can be used to read and write the surface of a
DVD, one can certainly affix toner to paper. The only limitation would be
the size of the toner particles. You ever try to clean that stuff up? It's
pretty darned fine. It'll go right through a standard vacuum cleaner bag.
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| Tom MacIntyre 2003-09-11, 7:24 pm |
| On Thu, 11 Sep 2003 17:15:57 +1200, "RussS" <yeah_right@roflmao.com>
wrote:
>Always disconnect from the power outlet. Besides being the way Comptia likes
>you to think, it is also a Health and Safety issue in many countries.
>Whether you use a wrist strap is your perogative, however many companies
>demand their use and to be perfectly honest if a client can see me I make
>sure I am using one. The major point to remember is that you are NOT
>earthing yourself or the machine - what you are in fact doing is balancing
>your voltage level with the machines level -
Correct.
Tom
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