Desktop power on surge when power strip switched on

I have had a couple of computers that do that.  From what I remember since a computer never 'shuts off', the computer looses power when the power strip is turned off so its doing a quick test to make sure things are working.  I think its something in the BIOS.  I wouldn't worry about it honestly.  I would ask why you turn off the power strip?

>> BeamerMT79 said:

I have had a couple of computers that do that.  From what I remember since a computer never 'shuts off', the computer looses power when the power strip is turned off so its doing a quick test to make sure things are working.  I think its something in the BIOS.  I wouldn't worry about it honestly.  I would ask why you turn off the power strip? <<

I turn the power strip off:

1. To remove a/c power to everything plugged into the power strip, especially the monitor.

2. To lessen the chance of a power flux to my equipment should there be a power failure during the night like a car hitting a telephone post.

3. To lessen the chance of damage due to a lightning strike while I'm sleeping without having to get up if a storm starts, or when I'm away from home.

Been turning off the power strip every night or when away from home for many, many years now.  This XPS-8900 is the first PC that I've owned (or helped friends with) that powers on momentarily when the power strip is turned on.  All of my previous PCs have been self built.  This is my first Dell desktop but I've helped 3 friends buy Dell desktop XPS-8500 and XPS-8700 and give them ongoing tech support.  None of their Dell PCs power on momentarily when the power strip is turned on.  

Wondering if the newer Dell PCs have low quality power supplies that have this characteristic.  My XPS-8900's power supply doesn't even have an on/off switch on it.  Just a receptacle for the power cord.  That's a first for me too.

Thanks,

Raptor88

*** RoHe said:

That's entirely  normal!

BIOS has an AC Recovery option which tells the PC what to do when it recovers from a "power failure". Since you turn off the power strip at night, that's the same as a power failure.

So when you turn the strip on in the morning, the PC powers on briefly to see what it's supposed to do when recovering from a power failure. If BIOS is set to "do nothing", the PC powers off again, and you have to press the power button to boot.

If you're lazy like me, you can set that BIOS AC Recovery option to "reboot". So as soon as I turn the power strip on the PC starts booting and I don't have to press the power button.  Just make sure your strip can handle the load of the PC booting plus monitor and HDD all powering on at the same time. ***

Thanks for your info!  I changed the BIOS AC recovery option to "reboot" like you and it works great.  Actually saves me from having to press the power on button on the PC so one less step.  And it alleviates my concern about a power on/off surge causing possible damage.  IOW, why create a power flux like circumstance in a normal power strip turn on every morning.

Thanks!

Raptor88

Glad that works for you.

Been turning my surge protector off for this vintage 2004 Dell PC since the beginning, with AC Recovery set to reboot. Press one button on the surge and everything turns on and PC boots. Lazy is good!

NOTE: If your friends aren't disconnecting the power to the PC at the mains, like you do, they won't see the PC power on briefly when they press the power button. It will just reboot when they press the power button...  

Don't want to argue, but BIOS setup for both those PCs have the same AC power recovery option as yours. I don't know if this feature is unique to Dell BIOS or if other PC brands have it too. I do know my 12-year old Dell Dimension 8400 has this feature so it's not something new, at least not for Dell.

Quoted from their service manuals:

XPS 8500
Power Management: AC Recovery — Power Off; Power On; Last Power State (Power Off by default)

XPS 8700
AC Recovery Allows you to select the action the computer takes when power is restored

Maybe you just never noticed the brief power up when the strip is turned on for those other PCs...?

Happys to you too.

EDIT: I wouldn't expect an AC Recovery option in BIOS on any laptop, Dell or otherwise...

RoHe said:

Maybe you just never noticed the brief power up when the strip is turned on for those other PCs...?

----------

Hi RoHe,

Definitely, no momentary power on/off when a/c power first applied on any of my friend's (or any other PC) that I've worked on.

I've verified that the momentary power on/off thing on my XPS-8900 is a function of the motherboard and not the power supply.  I connected two other known working power supplies taken from my previous PCs and my XPS-8900 still does the momentary power on/off thing with both.  Both of those power supplies never did that with the PCs that they were previously installed in.

Not a concern for me anymore since your tip about setting AC recovery in the BIOS to "on" works well.

Thanks so much for your help.  Your tip is so, so valuable to me.  Even with intensive Googling, I never saw that tip anywhere else.

Keep it warm,

Raptor88

I use a optiplex 620 and a optiplex 960 and both nave the bios set to stay off with loss of power.  I do not want them turning off and on with the way the power is here.  I just replaced a computer and 2 surge protectors  because of the electicy.  All the computers i have owned including the ones o have built have a setting for the machine to reboot or sty off.  That doesn't mean all do just the ones i have owned.  And when the power goes out theyy turn off of course and when it comes back on there is a power up and if just starts up.