Posted for Alan Brewster <[email protected]>: ------------------------ From: Alan Brewster <[email protected]> Subject: EMC Detective and Flushing Toilet Date: Fri, 9 Jul 1999 18:06:47 -0700 To: "'[email protected]'" <[email protected]>, "'[email protected]'" <[email protected]>
> This problem is the exact copy of one I had in the UK some years ago and > I am sorry to say that it is not an EMC problem. The issue is one of > reduction of creepage and crawlage on the output to the PC power supply. > Flushing the toilet causes rapid cooling of the soil pipe and hence > condensation to form. The droplets then fall onto the ceiling of the > room below in which the PC is located. The wet ceiling is in a state of > equilibrium saturation and the addition of one droplet causes the > release of one droplet. This then falls onto the PC and is entrained > into the case by capillary attraction. It ultimately finds its way to > the PSU and onto the circuit board. The output thus shorted causes the > supply to the mother board to be interrupted and hence the power down. > The current pulled through the short circuit lasts long enough to flash > off the water but not to cause the means of protection to operate and > the returning output voltage causes the re-boot. > The customer should be encouraged to tip up one end of his PC to cause > the droplets to find another path. > The fix is simple in that PVC plumbing should be made a available to > afflicted users. > The case in question I mentioned earlier actually suffered the short and > open issue at the wall socket which is another, but less endearing, > possibility. > This is the kind of problem that involves anal-ysis into the wee hours > and where being flushed with success brings piles of potential. > > Alan > ________________________________________________________________________ > _ > Alan Brewster > Compliance Certification Services > 1366 Bordeaux Drive > Sunnyvale, CA 94089-1005 > Tel: 408-752-8166 ext. 122 > Fax: 408-752-8168 > e-mail: [email protected] > http://www.ccsemc.com > > > ---------------End of Original Message----------------- -------------------------- Ed Price [email protected] Electromagnetic Compatibility Lab Cubic Defense Systems San Diego, CA. USA 619-505-2780 List-Post: [email protected] Date: 07/09/1999 Time: 17:53:24 Military & Avionics EMC Services Our Specialty Also Environmental / Metrology / Reliability -------------------------- --------- This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to [email protected] with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to [email protected], [email protected], [email protected], or [email protected] (the list administrators).
