Bill Jemison wrote:
> I have two distinct problems that may or may not be related. I
> appreciate any help or suggestions you can provide
>
> Problem 1) Two case fans that were included with the Antec don't seem to
> spin at all. These are both in the back of the case (one exhaust out of
> the top of the case and the other exhaust out of the back of the case.
> Both these fans are currently switched to M (settings are H M L).
>
> I can see the fans twitch at at start up but they don't run
> continuously. I've seen them run periodically but I don't know why they
> won't run now.
>
> FYI - these fans are both hooked up to the psu connectors marked "fan
> only."
>
> The fan by the PSU runs fine. I 've also added 120 mm fan at the front
> of the case blowing air into the case.
>
> Problem 2) When I shut down the system, I have an intermittent problem
> where the CPU fan continues to run. When this happens, I also still see
> a keyboard light. I thought I fixed this back in July but the problem
> has started again.
>
> I can press the reset button have the they system restart (and try
> shutting it down again) or I can turn the PSU switch off and on.
>
>
> System:
> Antec P180
> Antec TP3-650 psu
> ASUS A8N32 SLI Deluxe mb w/Bios version 1405
> FX-60
> 2GB RAM
> 2xNvidia GeForce 7900 GS
> Sound Blaster X-Fi XtremeGamer soundcard
>
> Thanks,
>
> Bill
The first problem is easier to answer.
The "fan only" PSU output, is a speed controlled output on the PSU.
A typical value for voltage on there is 7V. You would normally plug
in a "dumb" fan to it, a fan with no other features.
A fan with Hi-Medium-Low switch, expects to see 12V at the
terminals. When you use the three settings, the switch is
being used to drop the voltage below 12V.
If both methods are combined at the same time, there isn't
enough voltage to run the fan. The result is a twitch.
Try connecting the two Antec fans to motherboard fan headers,
assuming the current draw is low enough that the headers
can support them. They probably aren't powerful fans, so should
be fine. Then, use the switch H-M-L to select the speed you
want. Even the low setting should still result in the fan
spinning, if all is well. The assumption here, is that the
motherboard fan header is putting out 12V.
In problem #2, if you actually selected "shutdown" from the menu,
that should cause the motherboard to change the state of the
PS_ON# signal. PS_ON# is on the main ATX power connector, and
is something you could probe with a multimeter, to see what state
it is in. The levels on the signal are TTL logic levels, using
open collector logic. A logic "0" value means "leave the PSU on".
A logic "1" value means "switch off the main outputs". Table 16
on page 27 here, shows the voltage levels they expect. A level of
more than +2V on PS_ON#, should cause the PSU to switch off. The
"undefined" zone is for hysteresis and noise immunity. If the
motherboard is doing a good job, the only two voltage values you
should be seeing, is a voltage less than 0.8V ("on") and a voltage
pretty close to +5.0V ("off").
http://www.formfactors.org/developer...public_br2.pdf
If the motherboard signal driver is not working well, that can cause
the problem. Or the input on the PSU can be bad ("blind"). Measure
the voltage on the PS_ON# signal, both when the system is supposed
to be running, and when the system has been told to shut off, and
see what two values are present. You can leave the main ATX connector
plugged into the motherboard, and probe for contact from the backside
of the connector, where the wires enter the connector. You can pick up
GND from a black wire, or my preference is to use an alligator clip on
the multimeter lead, and clip onto a screw on one of the I/O connectors
on the back of the computer. That way, there is one less multimeter cable
to handle while working.
Paul
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