Either there is a bad connection somewhere between the barrel jack and the header pins (unlikely), or one of the power supplies is causing the problem. I would check the resistance between the jack contacts and the corresponding header pins, and then try powering via the headers with the known-good supply. If that's ok, then (with the load connected) look for sag and ripple on the other supply.
-- 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 beagleboard+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.