This was a long time ago but I believe it was the HDMI clock. We were able to disable HDMI clock output by recompiling the device trees.
Hope this helps. Jon On Friday, 5 January 2018 19:56:06 UTC-8, [email protected] wrote: > > Was the culprit for the 625Mhz noise found? We have a similar issue and > we suspect the USB. > > On Wednesday, March 4, 2015 at 7:07:19 AM UTC-8, Gerald wrote: >> >> 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]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/b6a3e0a6-4fae-4110-baca-a95b4e905478%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
