Prema 5017 / 8017

[Kosmic]

Each meter were not exactly at 0 so I removed the DC offset in post processing.

Just curious - what was the average difference from zero for those meters with shorted input?

HP 34401a = -0.63uV
Prema  = 3uV
Solartron = 5.4uV

The prema had my good shorting plug. a clone of the Keithley shorting plug.



The other shorts were improvised and can probably generate some kind of Thermal EMF.

It's also important to note that the 3 DMMs have not been calibrated and adjusted for quite some time.

[guenthert]

Thanks for the story. Now it's the opposite situation, that you can't find thru-hole packaged parts. For example direct replacement for LF356BN ain't easily available, you either have to go expensive hermetic TO-packages or bodge adapters for SOIC8 or SSOP parts.  Sure there are other parts in DIP that can be subbed, but I like to keep repairs as 1:1 when possible , unless I'm convinced in improvement.

Why replacement when you can get the original? https://anchor-electronics.com/price-list.pdf
LF356 in 8 pin dip for $1.50.  But yes, in general you're right, TtH is a thing of the (more and more distant) past.

[maginnovision]

Posting here because it makes sense to me. I have a Prema 5017 and anytime I plug it into the same outlet as my Datron 1082 multimeters(same place as my Datron calibrator) the Datron 1082's almost immediately lose their stability, fluctuating upwards of 100 counts. Has anybody else ever noticed this sort of thing with a Prema 5017 or 8017?

[Kosmic]

Anybody could take some measurements on the feet of their 5017 ? mine came without them and would like to replace them.

thanks!

[branadic]

Kosmic, have you checked:

https://de.farnell.com/okw-enclosures/a9257209/klappfuss-unterbau-schwarz-pk4/dp/775484
https://de.farnell.com/metcase/a9257207/klappfuss-unterbau-grau-weiss/dp/775472

but also the 3D-printed solution: https://www.eevblog.com/forum/metrology/prema-6048-teardown/?action=dlattach;attach=1524067

-branadic-

[dietert1]

Posting here because it makes sense to me. I have a Prema 5017 and anytime I plug it into the same outlet as my Datron 1082 multimeters(same place as my Datron calibrator) the Datron 1082's almost immediately lose their stability, fluctuating upwards of 100 counts. Has anybody else ever noticed this sort of thing with a Prema 5017 or 8017?

I remember looking into the EMI problems of the 5017. There are two switched regulators on the power supply board and one of them uses an open core inductor for storage. That one radiates RF. Somewhere above in this thread i reported more details. In our 5017 i replaced that inductor by a closed core storage choke. In addition i added ferrites for the flat cables running to the analog board and the front panel.
The 5017 meter also has some difficuties in its front end design. And there are reports that occasionally it doesn't turn on.

Regards, Dieter

PS: I reported my findings here: https://www.eevblog.com/forum/metrology/prema-8017-(sick-)-vs-tektronix-dm5120-vs-hp-34401a/msg5010733/#msg5010733

[Kosmic]

Kosmic, have you checked:

https://de.farnell.com/okw-enclosures/a9257209/klappfuss-unterbau-schwarz-pk4/dp/775484
https://de.farnell.com/metcase/a9257207/klappfuss-unterbau-grau-weiss/dp/775472

but also the 3D-printed solution: https://www.eevblog.com/forum/metrology/prema-6048-teardown/?action=dlattach;attach=1524067

-branadic-

Thanks branadic!

[Kosmic]

And there are reports that occasionally it doesn't turn on.

I had that problem too.

[Kosmic]

So, the foot of the 6048 do not fit on the 5017 (the hole and pin are not aligned correctly and the screw on the 5017 are screwed from the outside not inside).

I created a new model for the 5017 that fit nicely.



files are here: https://www.eevblog.com/forum/testgear/replacement-knobs-feet-and-fittings-for-test-equipment/msg5374745/#msg5374745