I suggest you add common mode chokes on HDMI, Ethernet, and USB. And on any additional connectors you have coming from the board.
Gerald On Wed, Mar 4, 2015 at 8:41 AM, Jonathan Mash <[email protected]> wrote: > Gerald, > > Thanks for the speedy response. We do have an enclosure for our product > but it is made of PC so it doesn't help much with EMC. The test lab also > tried "painting" it with this conductive paint but it didn't help enough. > I'll take up your offer and take this offline and contact you directly. > > Thanks, > > Jon > > On Tuesday, 3 March 2015 19:05:56 UTC-5, Gerald wrote: >> >> A lot depends on SW as well. Best way to pass is to put it in a box, but >> thee are some other things you can try that involve $$. >> >> You can contact me directly and we can have a lively discussion about >> your issues. >> >> Gerald >> >> >> On Tue, Mar 3, 2015 at 1:24 PM, Jonathan Mash <[email protected]> wrote: >> >>> Good Afternoon, >>> >>> First off, thanks to the BB community for making this such a great >>> resource for those working on the BBB and other boards. I have personally >>> spent hours on this forum. >>> >>> I am hoping that someone monitoring this group may be able to help me >>> and my company solve an EMC problem that we are facing the the BBB. *We >>> are open to paid consultations to aid in solving this issue (Gerald?)*. >>> We are building a product around the BBB that needs to pass FCC part 15 >>> Class B. We are having trouble passing the tests mostly around the 625 MHz >>> range. We were only 1-2dB above the limit in one lab and almost 10dB over >>> at another lab (yes, test equipment makes a big difference!). We tried it >>> with and without our custom shield attached. >>> >>> There is another thread here: https://groups.google. >>> com/forum/#!searchin/beagleboard/625/beagleboard/ >>> Y6BhtzKx2oY/YQ_xjmmkWusJ that seems to have the same problem. That >>> thread seems to have lost attention of the key players in this group so I >>> thought I would create another thread to bring more attention to this >>> critical issue. >>> >>> We have done some pretty aggressive modifications to the board and the >>> only way we can get the board to pass is by completely disabling (and >>> depowering) the LAN PHY. This was accomplished by removing FB4 and mangling >>> part of the device tree so we don't get a kernel panic on startup. Not an >>> elegant solution, I know. >>> >>> As suggested in the other similar thread, we tried shorting R136 but it >>> actually made the noise worse. >>> >>> We also tried disabling (removing Y4) the McASP oscillator as that was >>> also generating quite a bit of noise. Didn't help enough. >>> >>> Has anyone other than CircuitCo been able to successfully pass FCC with >>> the BBBw/Ethernet enabled as part of a system? CircuitCo was probably able >>> to pass because they could isolate the BBB with big filters on all cables >>> because they aren't selling the BBB as as system but as a component. >>> Because ours is a "Commercial System", we need to test with all cables as >>> they would be typically installed. No giant chokes for us. >>> >>> Thoughts? Comments? Suggestions? >>> >>> Thanks! >>> >>> Jon >>> >>> >>> -- >>> For more options, visit http://beagleboard.org/discuss >>> --- >>> You received this message because you are subscribed to the Google >>> Groups "BeagleBoard" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to [email protected]. >>> For more options, visit https://groups.google.com/d/optout. >>> >> >> >> >> -- >> Gerald >> >> [email protected] >> http://beagleboard.org/ >> http://circuitco.com/support/ >> > -- > For more options, visit http://beagleboard.org/discuss > --- > You received this message because you are subscribed to the Google Groups > "BeagleBoard" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/d/optout. > -- Gerald [email protected] http://beagleboard.org/ http://circuitco.com/support/ -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
