Somebody knows the RFL/Clarke HESS 828 Calibrator?

Marvellous bit of kit!.

Over a 1 minute period I saw 139.88mV to 140.19mV. This ties in with what you see. Even by itself, +/- 0.1% is not bad for the 3.5 digit setting thumbwheels. But ... the noise is not from the RFL but due to low level AC and RF pickup on the leads from the RFL to the DVM. A filter of say 1kohm and 1000uF across the DVM input and (my) display is rock solid at 140.02mV for minutes on end.

Got a 828 manual you could share?.

Hi,

Yes i've manual that i've download from the site of Clarke Hess.If you want i can email to you. The problem is that if i set 100 mV,all time my DMM read a instable value that oscillate continuosly from 100 to 99.5 to 101 to 99.3 etc. In the other range the last digits are more stable. I've tried to put the filter acrossss the input of dmm but nothing the value is always oscillating,in a second it's change 3,4,5 times!!!! "john jardine" ha scritto nel messaggio news:463cc3ff$0$2297$ snipped-for-privacy@free.teranews.com...

want

value

Yes. I'd be very pleased if you could email it!. My address is ... john.jardine [@ sign] idnet.co.uk

Sounds like the voltage 828 control loop itself is a bit unstable. Maybe a capacitor failing. My unit has some internal noise that is coming in from the 240Vac power inlet (LO-GND connecting link 'on' or 'off' it's still the same) but not the amount you are noticing.

PS: Just confirming my filter was wired as this ...

.---------. .---------. | CLARKE | | DMM | | HESS | | | | | | | | | ___ | | | POS o-----|___|--o----o POS | | | 1k | | | | | ---+ | | | | --- | | | | 1000u| | | | NEG o------------o----o NEG | '---------' '---------'