Jory and List Jory, You are right about the therminology, I just translated from spanish where we call it "corriente de ruptura" and I tried to explain it to the list in a not so technical way. If you remember, I didnīt say its a computer killer I posted it after looking at this message: >From: Clint Wynne <n5tbs@gte.net> >To: Dick Powell <dbpowell1@juno.com> >Subject: Re: KCW <kw2@acsu.buffalo.edu>: Re: computers >Date: Wed, 05 Aug 1998 17:18:36 -0500 >Message-ID: <35C8DA3C.CEE37DFE@gte.net> >References: <19980805.154658.13742.3.dbpowell1@juno.com> >The reboot is good for the memory. The thing that is bad is thermal >shock. >Thermal shock comes from turning the pc >on and off over and over. I replied to correct the above, but I think I made it worse, whoops ! I am not ofended, Neither I believe in a debate over Internet. But about computers I sell them I service them and sometimes things are not what they seem. Jory, You wrote: >Study, after study on the reliability of electronic circuits has shown that temperature cycling is the major >killer of electronics. In fact, Highly Accelerated Life Test (HALT) systems designed to quickly "age" >products to failure rapidly temperature cycle the system being "aged" while vibrating it. I know quite weel this theory, but I never had a computer fauling due to temperature. Even when the cooler fans stop. The computers nowadays are very well engineered and they take a lot of punishment. I also mentioned that mechanical parts go first. As you are an electric engineer I am going to explain you some facts about my area 90% of the computers sold here are IBM compatible clones, here the parts are dirctly imported mostly from china and they are not UL tested or anything like it. 10% are from major manufacturers as IBM, Compacq, Acer, We donīt see here makes like Del, or Gateway I donīt deal with Mac. Many of the clones and also IBM, Compacq. etc that I have seen got dammaged buy power failures and by switching on and off and I assumed a percentage is due to statics and Inductive kik, but not only because of the computer but for outside reasons and Iīll give you an example. My computers, the ones I sell and service never fail and the way I got down to zero failures was since I adopted the policy of installing the computer at the customers house myself, otherwise I donīt accept warranty. Since I am doing that I found out the following problems: I always go to the site and check the electric instalation. Electric system in Venezuela is based on 110V 60Hz 2 or 3 points sockets I keep having problems with therminology, you can correct me if you want ) You get Live, Neutral and ground. Many instalations either lack the ground, and people lazy enough cut the third prong and use it without grounding. If I am not mistaken the computer switch when you cut the current grounds to chasis and that gets rid of the inductive kick, and also protects the circuit against any statics, but what happens when you have no real ground ? I found other houses where they inverted the polarity and they have the live cable wired to the neutral and viceversa, !! For unknown reasons, sometimes I found live current comming trough the phone cable. Every time I go to a customers house I make sure the electric instalation is correct, I install either a voltage stabilizer or UPS and always make sure they have phone filter, and I check for polarity and grounding. Once everything is solved. I never had computers coming back. My older ones sold by me are about 20 machines sold three years plus, 8 of them are on 24hours a day on. Never had problems by heat, The only problem I had was with Hard disk drives, (normal wear) Four of those machines are still working with their original Hard disk drive, I changed the others before they failed completely. Every time I service them I check them thoroughly If I eve find bad blocks or hear strange noises when they start I change them. Also as I handle a specialized service, every time I assemble a machine for a customer I keep it running for a week, normally defective material will fail during this time. I think that is about what I have to say openly, Anything else we can discuss it if you e-mail me privately, donīt see reason to go on an electrical technical discussion on a piano list. Elian Degen
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