Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!uflorida!stat!fsu!loligo!pepke From: pepke@loligo (Eric Pepke) Newsgroups: comp.sys.mac.hardware Subject: Re: Memory Questions Message-ID: <381@fsu.scri.fsu.edu> Date: 27 Nov 89 14:27:44 GMT References: <4129@phri.UUCP> <3122@jarthur.Claremont.EDU> <5671@umd5.umd.edu> <3231@jarthur.Claremont.EDU> Sender: news@fsu.scri.fsu.edu Reply-To: pepke@loligo.UUCP (Eric Pepke) Organization: Supercomputer Computations Research Institute Lines: 41 In article <3231@jarthur.Claremont.EDU> wilkins@jarthur.UUCP (Mark Wilkins) writes: >I wrote: > >>>touch the power supply's metal case with your working hand and hold onto it >>>with the other hand while you work. > >In article <5671@umd5.umd.edu> jg13@umd5.umd.edu (Allon Stern) writes: > >>My question is, does the computer have to be plugged in to do this? It seems >>that in order to get a ground it would have to be. > > Sorry, forgot to mention that. With all static sensitive circuitry it is >necessary to leave the machine off but plugged into a grounded outlet. This is dangerous, especially if you are grounded through a different path. If the machine is plugged in to the wall, there is always the chance that you will touch the hot, in which case you may die. The best way is to ground yourself and the machine to a common ground that has nothing to do with power. You can use the grounding hole of an outlet, but only if you are absolutely sure that it is a true ground. There are a lot of outlets out there with floating grounds or grounds that are just tied to the neutral. If you do use a wall ground, be sure to use one of those plugs where the flat prongs are non-conductive plastic and only the ground prong conducts. Also be sure to use a ground strap that contains a resistor for safety; in theory, it is supposed to lower the current to below what usually causes fibrillation in a healthy person. In practice, those that live the longest tend to be those who avoid tempting fate and safety mechanisms. Better than a grounding outlet is a real ground, such as a cold water pipe. When you are connected to a ground, never go anywhere near anything that could be live. When you want to plug in the Macintosh to test it, first disconnect yourself completely from the ground. Eric Pepke INTERNET: pepke@gw.scri.fsu.edu Supercomputer Computations Research Institute MFENET: pepke@fsu Florida State University SPAN: scri::pepke Tallahassee, FL 32306-4052 BITNET: pepke@fsu Disclaimer: My employers seldom even LISTEN to my opinions. Meta-disclaimer: Any society that needs disclaimers has too many lawyers.