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- Won't wake up from stand by
December 29, 2006, 12:21 pm
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I decided to put my pc into stand by.
However I can't wake it up. No response from keyboard or mouse, or even the
on/off and reset buttons.
It is obviously in stand by as the psu fan is running.
I had to power off and reboot.(at least it fired up without the
aforementioned power problem recurring)
Is there some config change I should be making?
Re: Won't wake up from stand by
If your power supply has not been changed, and you still have your
apparent problem, is there any way to predict how a dodgy PSU
will behave ?
For "sleep" problems, the normal approach is to verify that an
ACPI HAL was installed during the install process. The BIOS has
to have ACPI enabled, and preferably set to some state like
S3 (which is suspend to RAM) versus S1 (which is blank the monitor
only). In S3 the PSU fan stops spinning, but the RAM is still powered.
In S1, the machine is in a higher power state, the PSU is still
running, the PSU fan runs, most likely the CPU fan runs.
If a motherboard has a bad BIOS (I had one), the OS will install
without ACPI. That is supposed to be pretty hard to put right,
via repair methods, but I could be wrong. I certainly never managed
to fix that machine's power states.
If Device Manager, when you check properties of "Computer", shows
ACPI blah blah, then that part of the process is in good shape.
For many people, they get that far, as only older motherboards
will have a completely wacked BIOS.
If your Device Manager shows ACPI, your next repair step, is to find
a copy of Dumppo.exe . Check Google for a download from ftp.microsoft.com .
The program is 12KB and runs in a DOS window. Via its "Administrative
Override", you can change the sleep state used by the OS. Typically,
this kind of repair is required, if a user changes the BIOS ACPI
setting from S1 to S3. On motherboards featuring the "overclock
recovery" procedure in their BIOS, sometimes the user's BIOS settings
get changed behind their back, and then when the user changes ACPI
from S1 ro S3, the OS needs to be "helped a bit", to set things right.
That is where dumppo.exe comes in handy.
But in your current situation, either your PSU by itself is defective,
or sometimes it can be a fault in the motherboard, overloading the PSU,
that can upset things. As I have a clamp-on DC ammeter, it only takes
a minute to check all the DC rails for improper consumption. It is
much harder to do that with garden variety $30 multimeter from
Walmart, as the currents flowing in a PC can be more than the meter
can handle, and with a garden variety meter, you'd have to interrupt
the current flow in some set of wires, for each measurement. That
would mean taking an ATX extender cable and hacking it to bits,
to measure the current. And decent current shunts, for making
precision high current measurements, cost a lot more than they
should (getting some manganin wire and making your own is a cheaper
way to fashion one, but it still needs to be calibrated somehow -
manganin has a low tempco and the resistance doesn't change with
Anyway, Google on dumppo, for more info on fiddling with ACPI.
But preferably, after your PSU issues are sorted. Since at this
point, it could be a voltage used for standby, that is overloading.