From owner-freebsd-questions@FreeBSD.ORG Sat Jul 28 18:37:39 2007 Return-Path: Delivered-To: freebsd-questions@FreeBSD.ORG Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id ECE7E16A419 for ; Sat, 28 Jul 2007 18:37:39 +0000 (UTC) (envelope-from erikt@midgard.homeip.net) Received: from ch-smtp02.sth.basefarm.net (ch-smtp02.sth.basefarm.net [80.76.149.213]) by mx1.freebsd.org (Postfix) with ESMTP id 70ED713C45A for ; Sat, 28 Jul 2007 18:37:39 +0000 (UTC) (envelope-from erikt@midgard.homeip.net) Received: from c83-253-10-135.bredband.comhem.se ([83.253.10.135]:50318 helo=falcon.midgard.homeip.net) by ch-smtp02.sth.basefarm.net with smtp (Exim 4.66) (envelope-from ) id 1IErAY-0003yB-7i for freebsd-questions@FreeBSD.ORG; Sat, 28 Jul 2007 20:37:38 +0200 Received: (qmail 76255 invoked from network); 28 Jul 2007 20:37:35 +0200 Received: from owl.midgard.homeip.net (10.1.5.7) by falcon.midgard.homeip.net with SMTP; 28 Jul 2007 20:37:35 +0200 Received: (qmail 14887 invoked by uid 1001); 28 Jul 2007 20:37:35 +0200 Date: Sat, 28 Jul 2007 20:37:35 +0200 From: Erik Trulsson To: fbsd2 Message-ID: <20070728183735.GA14756@owl.midgard.homeip.net> Mail-Followup-To: fbsd2 , "freebsd-questions@FreeBSD. ORG" References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.14 (2007-02-12) X-Originating-IP: 83.253.10.135 X-ACL-Warn: Too high rate of unknown addresses received from you X-Scan-Result: No virus found in message 1IErAY-0003yB-7i. X-Scan-Signature: ch-smtp02.sth.basefarm.net 1IErAY-0003yB-7i f098ab3893f073194d979722d6b11b65 Cc: "freebsd-questions@FreeBSD. ORG" Subject: Re: OT: pc power on X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 28 Jul 2007 18:37:40 -0000 On Sat, Jul 28, 2007 at 01:56:13PM -0400, fbsd2 wrote: > After a power outage my FBSD server does not restart automatically. > Someone has to push the PC power on button on the front of the case. > I tried to jumper the motherboard pins the wires from the power on button > go to but that did not work. It starts for 3 seconds then goes off. Of course, since the power button in front of the PC is not just a 'power on' button, but also a 'power off' button. The way it works is that when the machine is in a 'soft off' state then the PSU (Power Supply Unit) constantly delivers a small amount of stand-by power to the motherboard. When the power button on the front is pressed the motherboard will detect this and send a signal to the PSU to start running for real, after which the machine starts. If you then press the power button when the machine is running the motherboard will usually detect this and send a signal to the PSU to power down. (Although if the machine is fully up and running this action can sometimes be overridden by software.) > > How do I make the pc boot automatically after the power comes back on???? There is usually an option in the BIOS governing how the machine should react when power is returned. There are usually three choices labeled 'Soft off', 'Last state' and 'Power on' or similar. Not all BIOSes have such an option, but many do. Another option if you are not afraid of messing around with electrical stuff is to simulate the signal the motherboard sends to the PSU telling it to start. This can done by connecting pin 14 (PS_ON) and pin 15 (GND) of the 20-pin cable going from the PSU to the motherboard. (For a 24-pin connector the lines are numbered 16 and 17 instead.) Do be careful if you try this route though, and don't blame me if you damage something. -- Erik Trulsson ertr1013@student.uu.se