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Old January 4th 04, 02:57 AM
Jeff Green
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Everything is connected, near as I can tell, properly, including the four
pin power connector. I guess I was a little vague as to the sequence. I
double-check the wiring of the power switch to make sure it's on the right
jumpers. The machine works fine. Runs fine. I can run all my programs and
everything a good computer should be. Never gives me a hiccup when it's
running. Problem is, if my toddler daughter sneaks in and shuts off the
computer with the power button - it won't start back up with the button
unless I physically unplug the whole machine, wait until the red LED light
is off, and then plug it back in. Then it starts up fine. Not sure why I'd
have to power it down completely to get it to work correctly - fiddled with
most of the BIOS power management settings settings and it still seems to
happen.

JG

"*Vanguard*" wrote in message
news:y3rJb.36406$I07.115675@attbi_s53...
"Jeff Green" said in :
I have just installed a new NF7-S motherboard in my system. Every
time I shut down my computer won't power back up unless I disconnect
the power supply and re-connect it first. I tried to see if there was
a bios setting that might be causing it, but I don't see anything.
Any suggestions are appreciated. I'm guessing it's something simple,
but I just haven't dealt with it before.

JG


I think pin 14 is the PS-ON line (green wire) that the motherboard should
short to prove to the power supply that the power connector has been
attached to a motherboard. Check if pin 14 in the header on the mobo is
shorted to one of the ground pins (I suppose it is possible they put a 10

to
100 ohm resistor in the line but the resistance should be very low; I've
never personally measured the resistance from pin 14 to a ground pin).

The NF7-S also is an ATX12V compliant mobo. That means the 4-pin power
square connector from the ATX12V power supply goes to the 4-pin power

header
on the mobo. I thought that I read that the 12V connector wasn't an
absolute requirement -- except that the 20-pin power connector really

cannot
supply enough amperes over its 12V lines to supply the higher powered AMD
processors. Attaching the power supply's 12V 4-pin power connector to the
mobo header lets the mobo distribute the 12V current over 3 lines. Do you
have an ATX12V power supply (i.e., does it have the 20-pin big power
connector along with a small 4-pin connector)? Or spend lots more money

to
get an PSU tester for $15 to $25. A 10-ohm 10W resistor and a multimeter
work for me. But neither method substitutes for an oscilloscope to

measure
ripple but I'm not going to waste my money on this pricey goody.

You might also try checking that you have the correct wires from the case
front panel to the header on the mobo. Make sure the pwr wires go to the
pwr pins and the reset wires to the reset pins.

Although pin 14 (PS-ON) tells the power supply it is connected (when

shorted
by the mobo) to a motherboard, I've also heard some ATX power supplies
require some current draw to actually power up, like hooking it up to a

hard
drive. Are you trying to bring up the power supply with it connected

*only*
to the motherboard? I got a Fortron ATX12V model and it does come up when
the PS-ON line gets shorted to ground (but you really need to put a 10-ohm
10W load on each power line to ensure the voltage is valid under a load
rather than try to measure it with no load). If you just want to connect
the big (and small) power supply connectors to the mobo and not to the

other
devices (i.e., drives) then put a 10-ohm 10W resistor accross the 12V and
ground wires for one of the 4-pin Molex connectors. You can get this at
Radio Shack.

The NF7-S has some LEDs on the bottom or left edge of the mobo. For me,

one
lights up red and the other is green. There is no mention in the NF7

manual
as to what these LEDs are for. My guess is that the red LED indicates

when
the special 5V line is powered (the ATX power supply will still supply

this
special 5V as on when it is plugged in [and the switch on its backside, if
present, is in the ON position]). The LED tells you that the power supply
is supplying that 5V to the mobo (even when the system is "Off"). I don't
know what the green LED is supposed to indicate. Maybe it goes only when
the pwr switch is depressed and the power supply provides voltages on all
the other lines.

You don't mention how long the system stays up. If it stays up long

enough
to go into the BIOS screens, then check under the PC Health menu to see

what
voltages are listed. Maybe you haven't bothered to install a CPU yet or
don't have it properly seated with thermal paste/pad to the heatsink and a
fan. The BIOS might be set to shutdown the system if the CPU temp is too
high or if the CPU fan's RPM is too low.

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