Forcing Power Good

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I need to run an ATX power supply not installed in the computer.  Can
someone please tell me how to force the power good signal that comes from
the MB.  I believe I read somewhere that you short two pins on the PS
connector but can't seem to fine the article.

Thank you very much.

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Re: Forcing Power Good

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On the Mboard plug, connect Green wire to a Black.( paper clip ?.)Do Not use
the PSU witout a load, even if it`s just an old hard or floppy drive.
best wishes..OJ

Re: Forcing Power Good

well said 'bout the green and black .

What do you mean without a load?  If you plug a PSU into an old HDD
then isn't that a load, though just a small one.   Do you mean that the
PSU must have a significant load in order to operate properly.
Otherwise the   voltage? or current? may be irregular/jumpy.

Re: Forcing Power Good

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Switch mode PSUs work better under a load. Ask an expert. <g>. bw..OJ

Re: Forcing Power Good

On 23 Aug 2005 06:01:21 -0700,

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Many PSU have minimal load built in.  Rarely they don't.
Either way, this minimal load is below the common
manufacturer's spec of 2A on 5V rail (and sometimes up to
that much on 12V rail).  Less load often does work fine, but
is not guaranteed to like that the manufacturer specs.

An old HDD is generally enough, but a bit undesirable for
continued use.  Better to just put an appropriately sized
power resistor on it.  2.2 Ohm 20W works nicely for 5V rail,
one with an integral 'sink plate is even better.

Re: Forcing Power Good

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Can he make a piece of toast with that Kony ?. <g>.

Re: Forcing Power Good

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Thank you for you prompt reply.  Actually, I'm not trying to measure
currents or voltages but trying to evaluate the noise level of the PS fans.
You see, I just got two new high tech hearing aids and ambient noise is
about to take the top of my head off.  The audiologist says I will get used
to it especially after he reprograms the things based on my experience with
them.  I ha' me doots!

Thanks again.

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Re: Forcing Power Good

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Och aye the noo. It`s a pleasure.

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Re: Forcing Power Good

On Tue, 23 Aug 2005 10:32:38 -0400, "Jack Gillis"

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You do not need to do anything with Power Good, ignore it.
All you need is to short the PS-On line (green wire, pin 14)
to ground, and have enough load on it to stabilize the
output voltages.  Since the PS fans' RPM will be dictated by
the output voltage to a certain extent, it could be useful
to have that output reasonably near the running state
voltage.  Measurement with a multimeter of 12V rail level
should confirm it close enough to 12.0V, or whatever it's
normal level in the running system.

Re: Forcing Power Good

aha, you're right.  Power_Good is the grey wire, isn't it.
Power_On is green.
it was just a mistake in name.

I usually take a paper clip and connect those 3rd and 4th wires.  Green
and Black

PS_On and Ground

However. I don't think this is the way to go if you want to nkow if the
PSU is quiet.  And I don't think this is necessarily the way to go if
you want a quiet computer.

Anyhow. If you are testing a PSU, you should really put a PSU in a
computer, connect it to a HD and a CD drice, get it well loaded, so you
see it running typically. Then run out and tell somebody else to turn
the computer on!  Then  sneak towards the door and open the door a
fraction, and see you can take the noise, then decide if you want to
get closer!  If not, then call the guy in to turn if off again.
And seriously consider a  KVM Extender.    A quiet PSU will be quieter,
but if you can't stand noise at all, then it may not be quiet enough.
A KVM Extnder will remove all ambient noise from the computer.  it'll
move the noise elsewhere.

Re: Forcing Power Good

On 23 Aug 2005 12:55:09 -0700,

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LOL.  Wear soft soled shoes so you're more stealthy?

One of the issues I failed to mention previously is that
many decent PSU have fan throttling feature which increases
fan speed as the PSU temp rises.  Because of this, it is
necessary to have PSU loaded to the same extent the system
using it, would, else actually have it in that system in
it's typical running state, so the PSU is generating that
expected thermal output and fan has responded in turn at the
higher RPM.  

With most good PSU if you just short the power-on to run it,
the fan will barely be running but certainly be more than
twice as fast in an average system.

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... might be a bit overkill, usually putting a system under
the desk is sufficient if it was built with low noise in

Re: Forcing Power Good

Jack Gillis wrote:
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I've been through making my computer silent for over a year. I solved
it eventually.  I know what you're talking about.   I managed to
avoided all that!!

You're going the wrong way about this.  PSU fan is very quiet when you
jst connect the green and black wires.  It gets faster under a heavier
load. So your test won't do the test you think you want to do.

There are many sources of noise. Case fans can be bad, PSU noise is
also bad.  then CPU.

Noise is subjective. many people will sell you 'quiet components'. They
will make it quieter. But, once you get a quieter PSU you'll still have
the CPU fan. Anyhow. some quiet PSUs have fans that make high pitched

You are a special case,   the noise REALLY BOTHERS YOU, it's not just a
nuisance, it's a nightmare.

There are semi solution like trying quiet components and something I
did that helped most (but not enough for me).  Was I had this little
cupboard.  So, I knocked the backout, so there was breathing space in
there. And I put the comp in and closed the door!  That blocked a lot
of the noise.    For now, consider ear plugs and ear defenders while
using the computer. They have issues too, but let them be temporary.
Or turn off your hearing aids while you're on the computer!!

But ultimately, I wanted a better solution to end all the noise.
You may be happy with just a quiet component solution.

a KVM Extender solved it.  My KVM Extnder supports 30M.

You can get a USB Extender too, that uses a cat5 cable (USB to Cat5,
then cat5 to USB) and boosts usb to like 30M)

So the Box is downstairs Far away. and the keyboard monitor and mouse
are upstairs along with a USB port (a few USB ports actually).

I have a friend that had a similar problem. He just put the box just
outside his room and closed his door. He will probably get a KVM

I encourage you to email me if you have any personal question regarding
the noise.  But, incase anybody else is interested, it's better to post
here or at least post solutions here once you find them.

Re: Forcing Power Good wrote:

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About how much does a KVM Extender cost?  How many cables does it
use?  How thick are the cables?  Do they have large molded-on
connectors on both ends that would make it difficult to fish them
through walls?

What type of mouse do they support?  Is it PS2 only?   Thank you in
advance for all replies.
I am terribly cruel to my cat.  I give him so little canned food
that he has to eat some dry just to survive.  I won't let him
get on the table and eat off my plate.  I sometimes refuse to
open a window he wants to smell out just because it's too cold/hot.

Re: Forcing Power Good

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Daniel Prince wrote:
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Note: with the exception of 'that' green usb extender, I used google
images for pics.

When I got a KVM Extender some years ago off ebay, there were a few
Blackbox KVM Extenders going for about50.  A great deal, considering
Blackbox are usually very pricy.  And the UK is pricy.
It's very reliable. It's the first I ever tried, so I haven't
experienced  if there are bad ones or how they are bad.

I don't know alot about good makes of KVM Extenders and their prices.
Simply because I got lucky first time around, with a good deal on mine.

My particular KVM Extender is Ps2 only. But I could and I think have,
used USB keyboards with it before.

USB Keyboards have ps2 functionality in them, and can adapt to Ps2 -
with a little adaptor. (ps2 keyboards don't naturally support usb, and
need a larger size adaptor to adapt to usb,  as oppose to the little
ones -  those won't do it)

A large adaptor, for Ps2 keyb/mouse in a USB socket. Notice the Square
or Rectangular shaped thing in the cable.

A little adaptor. (for plugging a USB keyb or a USB mouse into a PS2
socket). One end is USB female, the other end PS2 Male.

I ran into that issue in the following threads

thread: Advice for a PS/2 to USB splitter device

newsgroup: in comp.arch
thread: is there a ps2 keyb/mouse compatible with usb?

newsgroup: alt.comp.hardware
thread: USB to PS/2

I have experienced bad KVM Switches. But not bad KVM Extenders, so I
can't advise on what KVM Extenders to get, except that blackbox is a
good make, though very pricy. I was lucky.

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It has 2 units, local where your comp is.  remote where your keyboard,
video(monitor) and mouse, is.

Comp Box------->KVM Local unit--------------->KVM Remote

2 KVM like Cables and a (typically very long) Cat5 cable.

In terminology,
KVM=3DKVM Switch, usually.   (you ask of a KVM Extender)

My KVM Extender uses cables similar to that of a KVM Switch. THe
difference is that instead of 3 connectors on each side. It has 3 on
one side and on the other sie it has one which is like a parallel port

So, I say KVM like cables..

I can't find pics of KVM Extender cables on google images. Or perhaps
it's just my KVM Extedner that is like that.

KVM (switch) Cables look like this (thanks to google images)

a bulky one

(a beautifully neat one.)

I had a bulky one for my KVM Switch, I should try a neat one..
Especially as I have A KVM Switch it is even more important 'cos they
use many KVM Cables.  I don't know if the neat one works, if it is as
good as it appears. or if it is what it appears to be.

My ones look like those KVM Cables. But each one of them, has at one
end the 3 keyb,vid,mouse(2*PS2 and VGA). And on the other end one's end
is a bit like a parallel port connector.

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see above pics..

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see above,  mine are ps2 only. You can get USB + PS2 KVMs nowadays
probably a bit more expensive. But..
a)you can use a USB keyb in a ps2 port anyway
b)you could get a USB Extender,

The advantage of a USB Extender is you can plug in USB devices ,
instead of just the ps2 keyb/mouse.

So if you did get a USB PS2 KVM,. the advantage wouldn't be the ability
to use a USB keyb/mouse (you can do that with a ps2 KVM, very easily,
with little adaptors). The advantage is that you could plug in USB
devices like printers and scanners.

The USB Extender I have cost about100.   It comes in 2 units, local
and remote, and you plug a cat5 cable in between. Getting up to a 30M
It's reliable enough to be suitable for a printer. But perhaps not
reliable enough for a keyb/mouse. But all I use it for is
printer/scanner.  Sometimes I have to unplug it and plug it in. So in a
sense it is reliable I just have to make a minor effort sometimes. IT's
ok 'cos the plugging in and out is at the 'local unit', the one  near
me .

But since then i've seen on ebay simple cheap USB Extenders using Cat5.
Maybe they are more reliable too.

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