The reference module is in a metal box and uses an external linear PS with internal separate regulation. I don't think its external EMI, but anything is possible.
Randy On Wed, Jan 28, 2015 at 10:28 PM, Hendrik Dietrich <don_he...@gmx.de> wrote: > > Am 29.01.2015 04:07, schrieb Randy Evans: > >> I bought two HP-3458A ref boards from John Daly (he no longer has any >> more) >> and they worked fine but have intermittent noise bursts. I suspect they >> were rejects from HP/Agilent. At some point I will probably replace the >> LTZ1000As and reduce the internal temperature set point for better >> stability. Has anyone else had any issues with these units? >> >> BTW, I packaged the units in an enclosure for a stand-alone reference and, >> except for the occasional noise bursts, seem very stable according to my >> HP >> 3458A and fluke 732A/ESI RV722 KVD. >> >> Randy >> >> > Hi Randy, > > Noise bursts, especially if they get back on track again, sound like > electromagnetic interference from your short description. > If applicable, turn of the CFL or LED lighting, replace the switch-mode > power supply with a linear one or even better a battery,, try a known > non-reject in place of the ebay reference module, spread some capacitors > on/around the module and/or invest in a metal box. > > Hendrik > > > > > _______________________________________________ > volt-nuts mailing list -- volt-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/volt-nuts > and follow the instructions there. > _______________________________________________ volt-nuts mailing list -- volt-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts and follow the instructions there.