Oh, there’s some reasonably high risk circuitry in these things. For starters, the input supply voltage range is 100 – 240V, it’s a 300W power supply so it’s going to be a switching supply with some nasty volts and switching currents in there. Then it’s a reasonably powered home audio unit, 30/40 volts maybe at an amp or two flying around. Plenty of potential to cause a fire in there if the design or manufacturing’s not quite spot on. T
----- Original Message ----- From: John Woodgate Sent: 12/06/12 06:56 PM To: [email protected] Subject: Re: [PSES] interesting recall by CPSC <snip> >Would love to see the root-cause analysis. There aren't many things these days that are likely to cause a fire in an audio unit. It's the subwoofer that burns up, and perhaps the most likely thing to burn is the cone of the driver; maybe the sound absorbent filling contributes. Diver cone fires have been known in the past, caused by audio amplifier output stage device(s) failing, passing DC through the driver voice-coil. Separate amplifiers now have protection against this, but it might be left out of a powered subwoofer. Of course, this is pure speculation. -- OOO - Own Opinions Only. See www.jmwa.demon.co.uk The longer it takes to make a point, the more obtuse it proves to be. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> ! All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: < [email protected] > - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]>
