#PS_ON always low-signal (PSU keeps running)

Hello,

my Asus A8N SLI Deluxe always has a low-signal on #PS_ON. So my PSU never
shuts down. When shutting down the Computer the USB-Connectors turn off,
Monitors goes to Stand-By,... but PSU and it connected coolers ar still
running. Than it is even not possible to shut the PC on again with the
normal Powerbutton. The only way to turn the PC off or on again is using
the switch on the backside of the PSU.
So I measured the #PS_ON signal and it is constant 0,7 Volt, so means a low
signal which tells the PSU to Power-On.
This is not depending on the OS (tested with Linux + Windows), not depending
on the PSU (tested with 3 working PSUs) and not depending on other hardware
(tested with only MB+PSU connected).

Stefan

"Stefan Heinrichsen" <> wrote in message
news:4698a379$0$5698$...
> Hello,
>
> my Asus A8N SLI Deluxe always has a low-signal on #PS_ON. So my PSU never
> shuts down. When shutting down the Computer the USB-Connectors turn off,
> Monitors goes to Stand-By,... but PSU and it connected coolers ar still
> running. Than it is even not possible to shut the PC on again with the
> normal Powerbutton. The only way to turn the PC off or on again is using
> the switch on the backside of the PSU.
> So I measured the #PS_ON signal and it is constant 0,7 Volt, so means a
> low
> signal which tells the PSU to Power-On.
> This is not depending on the OS (tested with Linux + Windows), not
> depending
> on the PSU (tested with 3 working PSUs) and not depending on other
> hardware
> (tested with only MB+PSU connected).
>
> Stefan

Sounds like a fault on the mobo then. I suppose you
could always fit a manual on/off switch on that line,
and operate it after windows has shut down.
As to a mobo fault, maybe a bad sensor is seeing high
temps and keeping the fans going until it cools (which
it obviously doesn't.) Have a look at what the bios
temp readings are and see if any are way out.
Might be worth a fiddle with bios power settings, too.
Pure guesswork, btw - I've not come across this one
before.
HTH,
--
Rob

I recently experienced an intermittent problem with a homebuilt computer
where the system wouldn't completely shut down (case fan would keep
running and keyboard would appear to have power).

After a bunch of research, I tore the system apart and reinstalled cpu,
memory, boards .... on the assumption that the power problem was related
to a bad connection. It seems to have worked.

It may be worth a try to rule out a simple "bad connection" kind of problem.

Good luck.

Bill

Stefan Heinrichsen wrote:
> Hello,
>
> my Asus A8N SLI Deluxe always has a low-signal on #PS_ON. So my PSU never
> shuts down. When shutting down the Computer the USB-Connectors turn off,
> Monitors goes to Stand-By,... but PSU and it connected coolers ar still
> running. Than it is even not possible to shut the PC on again with the
> normal Powerbutton. The only way to turn the PC off or on again is using
> the switch on the backside of the PSU.
> So I measured the #PS_ON signal and it is constant 0,7 Volt, so means a low
> signal which tells the PSU to Power-On.
> This is not depending on the OS (tested with Linux + Windows), not depending
> on the PSU (tested with 3 working PSUs) and not depending on other hardware
> (tested with only MB+PSU connected).
>
> Stefan
>

Helo,

Oldish Git wrote:
> "Stefan Heinrichsen" <> wrote in message
> news:4698a379$0$5698$...
>> Hello,
>>
>> my Asus A8N SLI Deluxe always has a low-signal on #PS_ON. So my PSU never
>> shuts down. When shutting down the Computer the USB-Connectors turn off,
>> Monitors goes to Stand-By,... but PSU and it connected coolers ar still
>> running. Than it is even not possible to shut the PC on again with the
>> normal Powerbutton. The only way to turn the PC off or on again is using
>> the switch on the backside of the PSU.
>> So I measured the #PS_ON signal and it is constant 0,7 Volt, so means a
>> low signal which tells the PSU to Power-On.
>>[...]
>
> Sounds like a fault on the mobo then. I suppose you
> could always fit a manual on/off switch on that line,
> and operate it after windows has shut down.

The anoying is that I still would always have to wait until Windows/Linux is
down and than press this button.
I nice workaround would be to have a circuit which measures the power for
example at USB and if it's down switch the line of and (like usualy) on
again when powerbutton is pressed. But therefore my knowledge of
electrotechnology is to little.

> As to a mobo fault, maybe a bad sensor is seeing high
> temps and keeping the fans going until it cools (which
> it obviously doesn't.) Have a look at what the bios
> temp readings are and see if any are way out.

I had a look and all sensor have good values (about 35°C / 95°F)

> Might be worth a fiddle with bios power settings, too.

Even already tried this. But I also resetet and updated the BIOS already so
I don't think there is anything misconfigured.

Thanks
Stefan

Bill Jemison wrote:

> I recently experienced an intermittent problem with a homebuilt computer
> where the system wouldn't completely shut down (case fan would keep
> running and keyboard would appear to have power).
>
> After a bunch of research, I tore the system apart and reinstalled cpu,
> memory, boards .... on the assumption that the power problem was related
> to a bad connection. It seems to have worked.

The only thing I didn't reinstalled yet was the CPU so I gave it a try
reinstalling it but it even didn't helped.

Stefan


>
> Stefan Heinrichsen wrote:
>> Hello,
>>
>> my Asus A8N SLI Deluxe always has a low-signal on #PS_ON. So my PSU never
>> shuts down. When shutting down the Computer the USB-Connectors turn off,
>> Monitors goes to Stand-By,... but PSU and it connected coolers ar still
>> running. Than it is even not possible to shut the PC on again with the
>> normal Powerbutton. The only way to turn the PC off or on again is using
>> the switch on the backside of the PSU.
>> So I measured the #PS_ON signal and it is constant 0,7 Volt, so means a
>> low signal which tells the PSU to Power-On.
>> This is not depending on the OS (tested with Linux + Windows), not
>> depending on the PSU (tested with 3 working PSUs) and not depending on
>> other hardware (tested with only MB+PSU connected).
>>
>> Stefan
>>