power distrabution

i have a dell 8400, and it seems if i unplug it, and plug it back in, that the computer comer automatically back on, but the dvd drives light up and my fan and cooling fan make a super lod sound, as if there rpms were turned way up. but the computer doent do anything else, so i unplug it because the fan are roaring so loudly, then if i play with it for a few seconds, it keeps doing it, untill 1out of 100 times, it actually starts like it suppose to.

summary: i unplug computer, only fans and drives get power it seems, the fan get really loud,as if they were supercharged, and it does this untill i unplug it, it happens like 50 times, utill it actually starts working.

Firstly a word of warning. You aren't doing your PSU any favours by constantly switch the power on and off, that's the time of maximum stress and you could end up blowing the power supply if you continue.

Now your "problem".

There's usually a setting in the bios to choose what to do after power failure (which is effectively what it sees). The three options are: off; previous state; on. It sounds like yours is set to on or (more likely) previous state. That's normal.

The other thing is that the fans are supposed to come on at full speed initially. For safety the default setting is full speed, with overrides according to the bios setting. At that time it hasn't loaded the bios, so the default (full speed) is used. That's normal too.

If you leave it alone (ie don't pull the power back out) does it eventually boot? If so, you'll probably find that the fan speeds settle down. That's still normal.

Also, unplugging power then restoring it very quickly may not allow the power supply to properly discharge. In that case the system may not have detected the power fail situation properly. It may think the processor is still running normally so doesn't go through a boot sequence. The solution is to allow a few seconds for the PSU to discharge. Again, that's probably normal.

If it doesn't boot and you've given it a few seconds for the PSU to discharge, then you've potentially got a problem. Try seeing what happens if you change the setting for state after power failure to "off". It may mean you have to press the power button to get it to come back on but it may also solve the problem.

oooooh......new lab.........
see how many times I can rapidly unplug/reconnect my PSU before it blows :w00t:

I should do this on my Win2k box
the PSU in it already blows :dry: :lol:

but seriously now.....

We are missing part of the story. Why do you unplug the computer in the first place? When you want to turn it off you should tell windows to shut down by pressing the button on the front or selecting shutdown from the start menu.

Unplugging your computer while it is dong somthing can result in data loss and other problems.

Quote:

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Originally Posted by zaphodiv

We are missing part of the story.

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No shit, Sherlock...we are always "missing part of the story".
That's what makes this fun.

A true story....
Customer spends half an hour describing the various symptoms her laptop is afflicted with.
No two issues are consistent or point to a common root.
Random reboots...
Garbled keystrokes....
Video either goes blank or artifacts...
"NTLDR missing or corrupt"...

"What are you doing when this happens and have you done anything differently of late- new software, plugged in a new printer...ANYTHING?"

"No."

"K then, we'll check it in under a diagnostic and try to see what's going on."

Pause....

Pause....

Wait for it....

"Well, my cat peed on the keyboard and I washed it off...do you think that might have something to do with it?"

:sick:

hahahahhaha