Date: Wed, 29 Jan 2003 18:58:40 -0800 From: Terry Lambert <tlambert2@mindspring.com> To: Matthew Dillon <dillon@apollo.backplane.com> Cc: Peter Wemm <peter@wemm.org>, Dale Woolridge <dale-list-freebsd-smp-2@woolridge.org>, freebsd-smp@FreeBSD.ORG Subject: Re: Over heating of the ABit BP6 motherboard Message-ID: <3E3894E0.1388D52E@mindspring.com> References: <20030130022752.1872F2A89E@canning.wemm.org> <200301300246.h0U2kTbJ084870@apollo.backplane.com>
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Matthew Dillon wrote: > It's most likely that the capacitors are simply being made from > substandard materials with higher internal resistances. Sometimes you > can get around that by specifying HF (high frequency) caps. Voltage > spikes above the capacitor's rating (or even just near the capacitor's > rating) tend to blow holes in the gap material, greatly reducing their > life span, but won't necessarily make them melt down. If these are electrolytics, not tantalum, then they are polar. One thing we used to do for fun when I was a kid was run a lamp cord with an electrolytic on the end of it, and a power switch on the wall, and connect the things to 125VAC. The things blew with the sound and force of an M-80, much more energetic than your standard firecracker. This sounds like a "shaggy dog story", but it helped me out with a related problem. Later in life, we had a terminal room that wasn't on a line conditioner, at the second college I went to. Chances were good that a Televideo 910 or 915 would smoke at least once a week, and curiously, it always happened on the hour. The problem was that it was a college, and in order to sync all the institutional clocks, it had an hourly voltage spike that would cause the polar electrolytics to blow, letting out all the "secret smoke". It's very common, in my experience, that people having problems with Apple AirPorts or other tight tolerance equipment, are in a place with an institutional clock, with the hourly voltage spike. People putting equipment in an institutional setting really need to be aware of the possibility that there's something endemic to their power supplies that could easily cook their tight tolerance hardware. -- Terry To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-smp" in the body of the message
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