Computer power problem

[Ps!pHeN]

I just finished my suitcase mod using my old dimension 2400 and now my computer auto boots when I plug it in the wall. I had to redo the Main power harness for the power switch and both leds (power/hd act) and I did something to mess that up, I'll fix it later,but even with the harness unpluged from the motherboard its still boots up? Anyone know what I could have done wrong?

[Frakk]

in the bios there is a setting called "after ac power lost"(in mine at least) that controls this.
how this works: there is always a minimal current through the motherboard (for things like the power switch) no matter if the pc is on or not(if the psu is plugged in and turned on - ac power on). you can usually observ this by the flashing onboard lan connector even when its off. in other words, it knows when you plug it in and unplug it and this setting lets you controll its behaviour after you connect it to the outlet or turn the psu on.

[Tom Farmer]

I had that problem, somehow it sorted itself out.

[Ps!pHeN]

If I reset the cmos it will autoboot when pluged in. I reset the settings in bios to stop it from doing that but when I shut the computer off it will not reboot. I said before that I redid the power button and leds for HD/Power so I have one comming from dell but it worked fine on the bench before install. So now after shutting down the comp I cant turn it back on, and when I unplug and plugit back to ac it starts to boot up then shuts down. The only way I can get it to boot up is to reset the cmos everytime. Anyone know what I am doing wrong?

[Frakk]

seems like your motherboard has problems. you might wanna doublecheck the switch as well, but you shouldnt need to reset the cmos every time.

[Guttenaffe]

Look for anything that can cause shorts on the underside of the mobo.

[Xato]

Shorting out ur mobo sucks... happened to me in my first mod. I could turn my comp on and off by kicking it... it was cool... untill i realised i shouldn't be kicking my comp.

It turns out my motherboard was leaning against a drive cage, as the mobo was too big for the case. I learnt my lesson though.

[Ps!pHeN]

Sorry for the late response I was out of town. I was wondering if I could still have a short on the motherboard if I can still boot up and run my machine after reseting the cmos? I have checked everything I know to check and I am still have the same problem. I will check out other message boards and see if I can come up with a fix, and thanks guys for all the help!!

[Frakk]

try to take it apart again and see if it works out of the case. if it does, its most like being shorted out in it.

[Ps!pHeN]

I fixed it!!! It was the switch all along. The only way I was able to get the comp to startup was to reset the cmos which in turn would reset the bios to the default setting "startup on ac power". So after I reset the bios to stop it from booting when I plugged it into ac, I would no longer be able to reboot after shutting down. I thought I should test my switch (which I should have done it the begining) by jumping the pins on the motherboard and low and behold the computer booted right up!! I hope I explained myself clearly in this and I want to thank all of you for helping me out.

[Frakk]

did you use a momentary or a rocker switch? it might clear things up because if you used a rocker switch and didnt switch it back to "open" after you powered the comp up, then the it would turn off after about 5seconds. after each cmos reset i assume you reconfigured ure bios, therefore you had to reset it before the next boot up.

[Ps!pHeN]

Momentary. I think the reason for the switch failure from the start was way too much heat from the soldering.

[Frakk]

yeah you might melted the contacts together and shorted it out. the great mistery is solved :D