On the topic of out of the ordinary I have seen a product that passed and then 1 1/2 - 2 hrs later it fails.
The problem was oxidation that occurred between the head of a screw and a piece of gasket material. The screw material was changed and presto, it passes. Regards, Josh Eric Lifsey wrote: > Dave et al, > > I'd suggest consideration of one other factor - ambient temperature. > > One experience I had, an EUT was failing emissions during OATS > measurements. After placing it in the conditioned OATS control room > to warm up, it was then returned to the turntable where it then > produced a passing result with margin. Until it chilled again. > > I believe many labs record temperature during measurements for their > reports. It might be worth a look. > > Eric Lifsey > > At 3:13 PM -0700 3/24/05, [email protected] wrote: > >> I was thinking about the recent US/Taiwan EMC issue discussed here >> and I thought I would apply "Inference to the best explanation" to >> it. There was much conjecture about what is going on but we still >> have no more than the original evidence. >> >> Inference to the Best Explanation: >> >> Evidence: >> >> E1: The device passed at the US lab >> E2: The observed signal frequencies, at the US lab, correspond to >> known clock frequencies >> E3: The device failed at the Taiwanese lab >> E4: The observed signal frequencies, at the Taiwanese lab, do not >> correspond to known clock frequencies (they are different) >> E5: The device passes at the Taiwanese lab when a ferrite is placed >> on the USB cable >> E6: The identical device was tested at both labs >> >> Hypotheses (rank ordered by me from best to worst): >> >> T0: The US lab is correct and the Taiwanese lab is in error >> T1: The Taiwanese lab is correct and the US lab is in error >> T2: The device has changed between the US lab and the Taiwanese lab >> T3: Both labs are in error >> >> How one ranks the hypotheses depends on how they rate the evidence. >> >> Dave Cuthbert >> Micron Technology >> >> ---------------------------------------------------------------- >> 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/listserv/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: >> >> Richard Nute: [email protected] Jim Bacher: [email protected] >> >> All emc-pstc postings are archived and searchable on the web at: >> >> http://www.ieeecommunities.org/emc-pstc > > > ---------------------------------------------------------------- > 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/listserv/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: > > Richard Nute: [email protected] > Jim Bacher: [email protected] > > All emc-pstc postings are archived and searchable on the web at: > > http://www.ieeecommunities.org/emc-pstc > -- Josh Wiseman Owner, A2Z Compliance CE Lab Manager, L F Research 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/listserv/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: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
