From owner-freebsd-hardware Mon Sep 29 22:51:55 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.7/8.8.7) id WAA04708 for hardware-outgoing; Mon, 29 Sep 1997 22:51:55 -0700 (PDT) Received: from wall.jhs.no_domain (vector.muc.ditec.de [194.120.126.35]) by hub.freebsd.org (8.8.7/8.8.7) with ESMTP id WAA04698; Mon, 29 Sep 1997 22:51:36 -0700 (PDT) Received: from flip.jhs.no_domain (localhost [127.0.0.1]) by flip.jhs.no_domain (8.8.5/8.8.5) with ESMTP id TAA24022; Sun, 28 Sep 1997 19:16:30 +0200 (MET DST) Message-Id: <199709281716.TAA24022@flip.jhs.no_domain> To: richard@pegasus.com (Richard Foulk) Cc: freebsd-hardware@freebsd.org, Mark Mayo Subject: Re: My monitor's got the Shakes... From: "Julian H. Stacey" Reply-To: "Julian H. Stacey" X-Email: Home: Work: X-address: Holz Strasse 27d, 80469 Munich, Germany X-web: http://www.freebsd.org/~jhs/ (including PGP key) X-address: Holz Strasse 27d, 80469 Munich, Germany X-tel: Work: +49.89.607.29788 Home: +49.89.268616 X-fax: Work: +49.89.607.32158 Home: +49.89.2608126 X-data-coms: Home: ISDN +49.89.26023276 X-company: Vector Systems Ltd, Unix & Internet Consultants. X-mailer: EXMH 1.6.9 on FreeBSD (Unix) In-reply-to: Your message of "Mon, 22 Sep 1997 00:24:45 -1001." <199709221025.AAA03297@pegasus.com> Date: Sun, 28 Sep 1997 19:16:29 +0200 Sender: owner-freebsd-hardware@freebsd.org X-Loop: FreeBSD.org Precedence: bulk Reference: > From: richard@pegasus.com (Richard Foulk) > Date: Mon, 22 Sep 1997 00:24:45 -1001 > Message-id: <199709221025.AAA03297@pegasus.com> Hi, Richard Foulk wrote: > > You might try opening it up and cleaning all the dust away with a soft > brush. Dust can make in run hot and encourage arcing. > > Don't get zapped by the high voltage. Unplug the monitor for a while > before opening it. _If_ you really must open the monitor ... Be aware some capacitors recharge on their own, without needing to be connected to a supply ! As I recall that's electrolytics, but it may apply to the tube as well, which is also a capacitor in its own right (think Leyden Jars & look in old Physics books etc :-) Look to see if the heat has cracked the discharge resistors that are usually strapped for safety across inbuilt (or even stored-in-a-drawer) high voltage capacitors. If they're cracked they should be replaced, but you must think about what voltage is on them first, even unplugged. Fiddling with the back of televisions & monitors can kill you if you get it wrong ... do a lot of thinking ... never use sweaty hands bear in mind your blood conducts a lot better than your skin ... so avoid being punctured by solder spikes ... never touch anything dubious with the inside of your hand, 'cos of tendency to reflex grip it, if you must touch, use outside of hand, dont even think of touching the HT section, & the big thick cable out of the side of the monitor. DC will electrocute you better than AC from the outlet, High voltages obviously more so too :-) ... best way to kill yourself ? .. current up one arm, throught the heart ... down the other arm ... try to avoid that scenario: Think rubber mats & shoes, have wooden sticks to prod with, not screwdrivers, keep one hand behind your back (not leaning on the table) If in doubt ... don't ! don't even think of it ! PS I spent a minute or 2 in the High Voltage lab at Leeds University years ago scared in the extreme ... in pitch dark, with about half a MegV or something ridiculous in the room, powered up .. some idiot's idea of a prank, I've also worked on the back of live colour TVs ... neither experiences are ones to relish ... I love 5V TTL & the feeling I'll blow the CPU, not me :-) "Take care" seems the best form of parting salutation ;-) Julian -- Julian H. Stacey jhs@freebsd.org http://www.freebsd.org/~jhs/