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General discussion

Power switch

Nov 30, 2004 9:11AM PST

This is my first time build. So far I have an IntelD865PERL motherboard with an Intel Pentium 4 2.26GH processor installed. I powered up the system to make sure the fans are working, my HDD LED and Power LED and reset work, but, the front panel power switch has no effect, it will neither turn the power on or off. I have checked the connections and they are right. Is this normal, do I have to wait until the OS is installed or should the switch work as things are?

Discussion is locked

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No. DO NOT add anything
Nov 30, 2004 10:01AM PST

solve the problem first. The switch should work from moment one.

If the switch doesn't turn it on, how does it get turned on [powered up]??? This is the clue.

Give us some answers. i can think of a few possibilities, but need your inputs first..

If there is any question about the switch itself, disconnect the wires from the mobo pins and MOMENTARILY short the two pins together with the blade of a small slot screwdriver.

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Re: No. DO NOT add anything
Nov 30, 2004 10:03AM PST

It powers up when I plug it in and flip the switch on the power supply in the back to on.

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In that case, if
Nov 30, 2004 10:51AM PST

the power button will shut it down if you hold it depressed for 4 to 5 seconds, the problem is that you have, in the BIOS, the "power up on power restore" [or wording to that effect] ENABLED. I run mine that way all the time so that the computer turns on as soon as I turn the UPS power switch on.

Not all BIOS's have this option, but it looks as if yours does. You can also change the power switch setting in the BIOS for instant off rather than the 4 second bit.

Let me explain how an ATX power supply works [when connected to a mobo].Any time that the power supply is plugged into a hot 120 VAC outlet [and the switch on its rear is ON], there is 5 volts [standby power] applied to the mobo [many have an LED on the mobo that lights from this]. This is why you can power up by LAN, modem, keyboard et al, and why the power switch is only a momentary contact. The logic circuits turn the other supply outputs on, the momentary contact simply starts the logic circuit to perform the full turn on.

So basically when you use the normal turn OFF procedure to turn the system off, it simply never goes completely OFF. The only way to turn that 5 volts off is to turn off the switch on the rear of the power supply or unplug the supply from the wall.

When you do that the internal mobo logic interprets that as a loss of AC power [a power failure]. If the BIOS is set to restore the system [turn it on] after restore of power failure, your system turns on. [that's you turning on the switch on the rear of the supply]

If you can't get in to see the BIOS yet turning it on by the PS and OFF by the 4 second hold in is just fine, until you get to set the power management the way that you want it.

An aside. If you have spread spectrum option in the BIOS be sure that it is disabled.

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Re: In that case, if
Nov 30, 2004 12:34PM PST

Yeah that did the trick, thanks alot for your info, it really eased my mind!!!!!

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(NT) (NT) Thanx, much for letting us know.
Nov 30, 2004 9:59PM PST
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Re: Power switch
Nov 30, 2004 11:56PM PST

check once more. follow the diagram for the connectors such diagram come with the motherboard this connectors can be very tricky to first time builders.