[volt-nuts] [Bulk] Re: 3458A reference boards on ebay

[Hendrik Dietrich]

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