[clue-tech] case type
Roy J. Tellason
rtellason at verizon.net
Sat Apr 11 22:58:48 MDT 2009
On Saturday 11 April 2009 06:40:20 pm Soleblaze wrote:
> Collins Richey wrote:
> > Here's a stupid question. How does one tell the form factor of a
> > computer case (atx, or ...)? I have an old but still usable case with
> > a dead motherboard, so how do I know what kind of replacement board
> > would fit?
>
> From what I remember the biggest difference between AT and ATX was that
> AT power supplies had an actual button that would attach to the front of
> the case, while ATX would use a wire that goes from the motherboard to
> the button.
>
> I'd probably measure the board and look it up. If it looks like a
> regular sized case, it's probably ATX. Wikipedia is also your friend:
> http://en.wikipedia.org/wiki/Comparison_of_computer_form_factors
Oh heck, I didn't think we were talking about AT vs. ATX, I thought we were
talking about ATX vs. ITX and some of the other newer variants. I didn't
think that anybody besides myself was still using AT-cased stuff. :-) (BTW,
if anybody needs some older stuff feel free to contact me offlist, I have
bunches of it.)
AT cases have the same PS connector that goes all the way back to the original
PC, or I should probably say connectors, since they were usually a pair of
them, though I can't see any reason why they couldn't be a single connector.
The key point there is to keep the black (ground) wires together in the
middle where they meet. They also typically have the older-style 5-pin
(larger) DIN connector for keyboard, and mostly don't provide a mouse
connector -- that's handled separately, and some of what I have on hand here
uses a slot bracket with a short cable going to a pin header, though I think
I have one that does have a pair of mini-DIN connectors...
ATX boards use a single molex connector with 20 or 24 pins (and sometimes an
extra one for MB power besides), a bunch of I/O that's all on the MB,
typically a metal shield plate that stays with the MB as someone else
mentioned, and something of a different form factor than AT boards do. They
also typically expect 3.3V power (which AT boards don't) and a +5V "standby"
power that's on all the time that the machine has power, which is used for
the wakeup stuff, whether it's the power switch, wake-on-LAN, wake-on-ring
(modem), etc. functions, which are present to varying degrees and enabled
or not in the BIOS via the setup stuff in CMOS. Typically the keyboard and
mouse connectors are 6-pin mini-DIN that are stacked vertically. There are
probably a number of other differences that I'm not thinking of at the moment
besides.
Then there are variants of ATX, like ITX, and I can't recall what else,
that are more a matter of size than anything else.
--
Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space, a critter that can
be killed but can't be tamed. --Robert A. Heinlein, "The Puppet Masters"
-
Information is more dangerous than cannon to a society ruled by lies. --James
M Dakin
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