From owner-freebsd-questions@FreeBSD.ORG Tue Mar 23 08:10:15 2010 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 ADC511065673 for ; Tue, 23 Mar 2010 08:10:15 +0000 (UTC) (envelope-from freebsd-questions@m.gmane.org) Received: from lo.gmane.org (lo.gmane.org [80.91.229.12]) by mx1.freebsd.org (Postfix) with ESMTP id 3B80D8FC18 for ; Tue, 23 Mar 2010 08:10:15 +0000 (UTC) Received: from list by lo.gmane.org with local (Exim 4.69) (envelope-from ) id 1NtzBm-0005Rq-4F for freebsd-questions@freebsd.org; Tue, 23 Mar 2010 09:10:14 +0100 Received: from pool-71-166-134-186.washdc.east.verizon.net ([71.166.134.186]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Tue, 23 Mar 2010 09:10:14 +0100 Received: from nightrecon by pool-71-166-134-186.washdc.east.verizon.net with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Tue, 23 Mar 2010 09:10:14 +0100 X-Injected-Via-Gmane: http://gmane.org/ To: freebsd-questions@freebsd.org From: Michael Powell Followup-To: gmane.os.freebsd.questions Date: Tue, 23 Mar 2010 04:09:31 -0400 Lines: 58 Message-ID: References: <20100321101137.GA8202@melon.esperance-linux.co.uk> <4BA601B6.1050807@onetel.com> <1269327949.3708.75.camel@redwood.bukolt.lan> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7Bit X-Complaints-To: usenet@dough.gmane.org X-Gmane-NNTP-Posting-Host: pool-71-166-134-186.washdc.east.verizon.net Subject: Re: Also have a dead box [ WAS: Re: OT: dead box ] 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: Tue, 23 Mar 2010 08:10:15 -0000 Corey John Bukolt wrote: > On Sun, 21 Mar 2010 11:23:34 +0000 (06:23 CDT) Chris Whitehouse wrote: >> When you press the power button does the cpu fan or the power supply fan >> spin for a moment then stop? That's a sign that something on or plugged >> in to the motherboard has blown. Unplug things and test again. >> >> Chris > > Just a few days ago, I was helping a friend build a system (with all > brand new components, I might add) and we had this very problem. After > sticking in the CPU and RAM and hooking up and turning on the PSU, the > green LED on the motherboard turns on. However, the second the power > button is pressed, everything flashes for a second, then turns back off. > The green LED on the motherboard also remains on. The only way to get > it to flash again is to turn off the PSU, wait, then turn it back on. > We tried re-seating everything, to no avail. > > Reading this thread, someone else mentioned beep codes and that if there > were none, it's most likely a fried motherboard. > > Can anyone else confirm this? > Beep codes may be available, but the nature will depend upon the manufacturer and the BIOS. Different manufacturers will produce different products. In the bad old days the most common beep codes were designed to indicate a video BIOS did not initialize, and then the main area of codes indicated something wrong in the memory subsystem. Pretty much if they made it past these two points the board would boot. And, of course, you need a speaker hooked up which I commonly don't because I don't want any beeps. One thing to be aware of with regard to modern day motherboards and power supplies. I don't recall the exact standards nomenclature, but they are spelled out in a spec. Modern day motherboards will have a main power connector with either 20 or 24 pins. Some are wired so that a 20 pin power supply cable can only go into some of the pins of a 24 pin connector, leaving 4 open. Some power supplies have a split cable which has a 20 pin and a 4 pin that can be hooked together and will occupy all 24 pins of a 24 pin connector. In either case, there is also another second power connector which is usually fairly close nearby to the CPU socket. With slightly older boards this will be a 4 pin and newer boards it will be an 8 pin. On older power supplies there may be only one 4 pin cable designed to plug into this connector. Newer models will usually have a cable that splits into two 4 pin plugs, so as to be able to plug both into an 8 pin socket while retaining backwards compatibility with the older 4 pin boards. This second connector goes to a high current 12volt rail within the power supply and drives all those 'multi-phase' regulators near the CPU. One thing that is consistent is motherboards will not even attempt to boot if this second power cable is not connected or cannot supply sufficient amps. Some power supplies may even beep or have an LED that flashes red. Overlook this and the board will never boot. -Mike