From owner-freebsd-questions Sun Feb 6 11:56:53 2000 Delivered-To: freebsd-questions@freebsd.org Received: from jason.argos.org (a1-3b058.neo.rr.com [24.93.181.58]) by builder.freebsd.org (Postfix) with ESMTP id 865143DF6; Sun, 6 Feb 2000 11:56:33 -0800 (PST) Received: from localhost (mike@localhost) by jason.argos.org (8.9.1/8.9.1) with ESMTP id OAA06575; Sun, 6 Feb 2000 14:57:01 -0500 Date: Sun, 6 Feb 2000 14:57:01 -0500 (EST) From: Mike Nowlin To: Jim Manley Cc: freebsd-questions@FreeBSD.ORG, freebsd-stable@FreeBSD.ORG Subject: Re: Zip Drive Weirdness In-Reply-To: <4.2.2.20000206092657.00a34580@127.0.0.1> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG > I installed a parallel port zip drive on my 3.4-stable BSD box. With the > zip drive powered up and connected to the FBSD box, the FBSD box will > not start (Turn on the power, the box doesn't boot). I can hear the power > supply start up but nothing else happens. > > If I power down the zip drive, the FBSD box fires up normally. I have seen similar problems with both serial and parallel ports.... We bought a set of 20 identical 486's a while back that would refuse to start up if the external modem was turned on. If you start the computer, THEN turn on the modem, they'll run just fine until the next power cycle. After lots of head-scratching, it turns out that there was a fair amount of voltage feeding back into the power supply, and the cheap "self-protection" circuitry in the PS was getting tricked into thinking that the PS had failed. We found two ways to fix this: 1) Put some beefy diodes in series with the +5V lines coming off the power supply... Bad idea, but it proved where the problem was (sort of) coming from... You probably wouldn't want to run it this way normally. or... 2) Get a real power supply. It's amazing how we'll spend $12000 on our latest 1900MHz Quad-Xeon Super-Duper game machines, but trust them to a $29 power supply that's about as well-designed as a Ford Pinto. --mike To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message