AT compatible Mainboard using ATX PSU

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Hi, my Gigabyte 6BXE has seen the PSU originally supplied
go south.
The Manual sites this board as being of "ATX form factor"
and talks about being "AT compatible".
I have a 450W ATX PSU available to fill the job but find there
is no ATX 4 pin socket on the GA-6BXE PCB.
What might I be able to do with a soldering iron to have this 'old' board
powered by the newer ATX PSU?
Links to the Manual and MB.


Re: AT compatible Mainboard using ATX PSU

On Tue, 13 Jan 2009 19:49:07 +1000, clem

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Back then the motherboards tpically used the 5V rail to
power the CPU voltage regulation subcircuit on a
motherboard.  They used less current than today's CPUs, and
the ATX connector has multiple leads and pins for the 5V

Therefore, you don't need a 4 pin 12V connector to make it
work.  Any ATX PSU should work providing it has reasonable
5V current capability and is not overly biased towards
providing (and monitoring for shutoff protection purposes)
12V current.

In other words you will likely be able to use that PSU with
no problems as-is, since hard drives and fans put a load on
the 12V rail and there is often a load on the rail from a
resistor in the PSU as well.  If you have a problem where it
does shut down from inadequate load on the 12V rail you can
instead use an older generation PSU with a higher 5V current
to 12V current ratio, but given the age of the board, the
relatively low amount of 5V current used, this is not likely
to be necessary.

Re: AT compatible Mainboard using ATX PSU

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Based on your response I installed the ATX PSU, thanks.
Not to be confused with any other fault which may have
caused the old PSU to implode, I can report the HDD LED
lights when the soft start is initiated and then immediately
is out. There is no other response from the system.
Searching the new PSU I have not been able to find any
more information other than that on the case of the PSU.
The name ULTRIX is tied to a number of products and services.
Here are the specs as listed on the case.
DC Output Max:
+3.3V = 18Amp
+5V = 30Amp
+12V = 19Amp
Model 450U v1.3

Seems to me the CPU/HDD is not getting told to Start.
Similar occurs on a "standard' ATX system when you leave off
that 4pin connecter from the PSU.
Is all of that any help?

Re: AT compatible Mainboard using ATX PSU

On Tue, 13 Jan 2009 20:45:38 +1000, clem


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At that point, does the PSU fan keep spinning or it stops as
well?  If the PSU fan keeps spinning, indicating main power
rails are still powered, it is most likely the board has
failed to POST.  If the PSU fan stops, it seems the PSU
itself is bad or the board has a short and PSU working
properly, turns itself off.

The other possibility that comes to mind is what I mentioned
briefly previously, that if there is not enough load on the
12V rail (or rarely, on another like the 3.3V rail), the PSU
may sense the out of spec voltage from inadequate load and
shut itself off.  If this is the case, the fan will not be
spinning.  Again I think this is unlikely the case because
the system doesn't use much 5V current either, and the hard
drive(s) and fans should load the 12V rail enough for "most"
PSU, but I don't know exactly what your PSU is like.

If the fan stays running and you have a multimeter, take
voltage readings particularly of 3.3V, 5V, and 12V rails.

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While this is what happens with a newer system usign a 4 pin
connector, that is because such a system won't have any
power for the CPU because the 4 pin connector supplies that
12V power.  With your board this is not a factor, it uses 5V
power supplied by the main 20 pin connector.

Examine the board, especially check for vented capacitors
around the CPU slot, bulged out on the top or bottom or
crusty residue.

The specs for your PSU indicate it has a good ratio of 5V to
12V current, this factor that I mentioned previously should
not be a problem.  However the brand seems generic so I
would wonder about the quality of the PSU.  Even then, a
generic 450W should still be able to run that system.

My best guess would be that either the board or some parts
plugged into it or the PSU are damaged, or the mainboard
battery is dead (some boards only lose settings if the
battery is dead while others won't POST at all), or you just
need to clear CMOS while AC power is disconnected.

Try stripping the system down to minimal parts.  CPU,
heatsink/fan, 1 memory module, video card.  Substitute a
different video card if you have one, especially an old PCI
card would be a good one to try as sometimes that'll give
display when an AGP card wouldn't.  Leave drives and other
cards unplugged from both the mainboard and PSU since the
goal is only to see if you can get the system to POST,
display any info on the monitor.  Also if the monitor has
more than one input, check that it is set to the correct
input as it may default to a different one (for example an
LCD defaulting to DVI input but the video card has analog

If the system doesn't even keep the PSU fan running, lastly
unplug everything from the PSU, plug the PSU only into a
hard drive, and jumper the PSU's PS-On pin to ground with a
paperclip or wire.  At that point the PSU should turn on and
stay on, if it does not stay on then the PSU (or if you're
very unlucky the hard drive itself, but you can then try a
different drive next) is the problem.

Re: AT compatible Mainboard using ATX PSU

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Negative, PSU shuts down.

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Persisting with disconnecting components and powering up I
eventually excited smoke from the floppy  [A:/] drive power connection.
Replacing that drive and allowing a boot to complete Windows is
now running.
Without getting overly excited there is a new problem.
Immediately following the POST video beep the case speaker
begins emitting equal length long beeps (1 on 1) alternating the pitch.
Emulating a "hee haw" type sound signal. As great as it is to have
a working machine again, the dog is objecting to the din!
OverTemp alarm?
Case open alarm?
I have set CPU temp alarm to "Off" and Fan Fail Alarm to "Off".
The jumper (J12) for the case open function is open.
In the Chipset Features screen I have Reset Case Open status
 set to "Yes" and Case Opened set to "No".
Voltages are running at 5.05V and 12.58V.
Vcore is at 2.04V

Some thoughts on this din?
So far I am scratching up little info on beep codes.
Award BIOS v4.51PG
Plug n Play Extension v1.0a
02/06/2001-i440BX-8671-GA6BXE00C-00    Gigabyte 6BXE

Re: AT compatible Mainboard using ATX PSU

clem wrote:
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Check the hardware monitor page, if there is one, for
a temperature, voltage, or fan speed which is abnormal.
The "donkey siren" sound, is an indication that a
monitored parameter is outside its acceptable values.
It is hard to say, what other things might be lumped
under the donkey siren alarm.

And you'd need a manual, to verify that all the necessary
jumpers are present and installed correctly.


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