From owner-freebsd-questions Wed Dec 25 20:16:35 1996 Return-Path: Received: (from root@localhost) by freefall.freebsd.org (8.8.4/8.8.4) id UAA05889 for questions-outgoing; Wed, 25 Dec 1996 20:16:35 -0800 (PST) Received: from diablo.ppp.de (diablo.ppp.de [193.141.101.34]) by freefall.freebsd.org (8.8.4/8.8.4) with SMTP id UAA05884 for ; Wed, 25 Dec 1996 20:16:32 -0800 (PST) Received: from freebie.lemis.de by diablo.ppp.de with smtp (Smail3.1.28.1 #1) id m0vd7F7-000QadC; Thu, 26 Dec 96 05:16 MET Received: (grog@localhost) by freebie.lemis.de (8.8.4/8.6.12) id EAA26699; Thu, 26 Dec 1996 04:05:31 +0100 (MET) From: grog@lemis.de Organisation: LEMIS, Schellnhausen 2, 36325 Feldatal, Germany Phone: +49-6637-919123 Fax: +49-6637-919122 Message-Id: <199612260305.EAA26699@freebie.lemis.de> Subject: Re: Frying your monitor In-Reply-To: <199612160608.BAA27712@tor-srs1.netcom.ca> from ANDRE BERNARD BAILEY at "Dec 16, 96 01:08:29 am" To: abbailey@netcom.ca (ANDRE BERNARD BAILEY) Date: Thu, 26 Dec 1996 04:05:31 +0100 (MET) Cc: questions@FreeBSD.org (FreeBSD Questions) X-Mailer: ELM [version 2.4ME+ PL28 (25)] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-questions@FreeBSD.org X-Loop: FreeBSD.org Precedence: bulk ANDRE BERNARD BAILEY writes: > Hi, > > I bought a FreeBSD from a book shop and while reading I found out that > I can fry my monitor. I am new to unix os and would like to know what > should I do not to fry my VGA monitor as I am at the stage where I am > ready to install. Well, why don't you read what the book says? Here it is (page 116): How to fry your monitor Remember that a monitor is just a glorified TV? Well, one of the design constraints of real TVs is that they have only a single horizontal frequency and only a single vertical frequency. This simplifies the hardware design considerably: the horizontal deflection uses a tuned circuit to create both the deflection frequency and the high voltage required to run the tube. This circuit is comprised of a transformer (the line transformer) and a condenser. Run a line transformer even fractionally off its intended frequency and it will run much less efficiently and use more current, which gets converted to heat. If you run a conventional monitor off spec for any length of time, it will burn out the line transformer. You don't have to roll your own X configuration to burn out the monitor: ten years ago, the standard display boards were CGAs and HDAs, and they had different line frequencies and thus required different monitors. Unfortunately, they both used the same data connector. If you connected an HDA (18.43 kHz line frequency) to a CGA monitor (15.75 kHz, the NTSC line frequency), you could expect smoke signals within a few minutes. Modern PC monitors no longer use line transformers, and there are few of them which can't handle at least a range of line frequencies, but this doesn't mean you can't damage them--you'll just burn out something else, frequently the power supply. In addition, just because the monitor displays correctly doesn't mean that it is running in spec. I have a rather elderly Eizo 9500 (called Nanao in the US) which has three frequency ranges: (exactly) 31.5 kHz, 48 to 50 kHz, or 64 to 78 kHz. In fact, it will display at any frequency between 48 and 78 kHz, but if it were run at 57 kHz for any length of time, I would be in for a hefty repair bill. The moral of the story: Never run your monitor out of spec. If your display is screwed up, there's a good chance that the frequencies are out, so turn off the monitor. Monitors aren't the only thing that you can burn out, of course. If you try hard, you can also burn out chips on some display boards by running them at frequencies which are out of spec. In practice, though, this doesn't happen nearly as often. > The # on the cdrom is ISBN 1-57176-079-2 Really? Unfortunately, that doesn't identify the book uniquely, but I haven't seen one with this ISBN. I'm assuming that you have "The Complete FreeBSD", but my copy has the ISBN 1-57176-159-4. Greg