Hi group I hope I can get some advice on an issue with a power supply. It was supplied, as a separate unit, with a Maxtor portable hard disk drive that we use for backups in the office (UK based). The drive sits on a pc case. The supply is manufactured by DVE, model number 0421S. It provides 12V dc at 3A. Rated input is 100-240V, 50/60Hz, 1.2A. Its CE marked, UL listed and has a TuV mark stating BSEN60950. It's marked as double insulated. I guess its around 18 months old and has had an "easy" life in the office, with no visible case damage.
After connecting the data cable (Firewire, already connected to the pc) to the drive, I touched its metal case while touching the outer of the dc connector and got an unpleasant tingle. I measured 230 V from the metal case to the outer of the dc connector (not connected to the portable hard disk). To isolate the drive from ac ground, I removed the data cable from the drive and measured 230V from the metal case to ac power ground (the drive is insulated from the pc case by plastic feet). Current was around 0.2mA. When the dc connector is connected, the drive performs normally. The drive was removed for secure storage when we left the office over the Easter holiday. In normal use it remains connected to one pc for weeks at a time. It would be exciting to move the drive from pc to pc! I couldn't find a recall notice for the DVE part number on Google. I'm interested in possible failure modes (I'm not a switch mode power supply expert) that could result in this shock hazard. I assume its due to degrading components and will get worse! Many thanks in advance Stuart Miller Ablewisp Limited www.ablewisp.com ph: 01803 843502 -- - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] 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] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
