Calibratory D-105 DC Precision Voltage Reference Standard

[HighVoltage]

You guys have it all wrong ....

May be because of the "special soldering" and spots on the pcb and "amazing" workmanship, this 03458-66509-LTZ1000 reference has ultra special drift and accuracy abilities, surpassing any modern keysight reference.

[ManateeMafia]

I noticed that 732A and knew it was him. I also wondered if someone else caught it but I can see it was obvious.

Thanks for the link. eBay is certainly full of scammers and I consider myself lucky there is a well educated community keeping everyone else informed.

MetroPhool? I like it. Every auction that uses the word NIST will make me think about it.

[HighVoltage]

Nice investigation work here, butterfly
Hopefully lots of people will find this, before they buy anything of this MetroPhool
 

[Awesome14]

But the standard is designed to be operated in a controlled environment not to exceed 50% RH, and with a temp between 17-26C.

This is the first time, as far as I am aware, that you have specified this humidity limitation and, having just checked your ebay sale offer, there is no mention of that limitation there. I find that rather odd, to not mention a basic, critical design parameter. Heck, even my TV comes with that information clearly supplied.

You say:

I haven't done any testing at RH above 50%, because I work in a standards lab with a controlled environment (RH 30-40%). I wasn't aware there was a market for high-humidity, low-cost standards. But, in any event, the unit is not designed to operate above 50% RH or above 26C.

Didn't it ever occur to you that: 1) Buyers of cheap voltage references aren't likely to be people running standards labs with highly controlled environments (if you can afford the air-con you can afford the 732), 2) that 50% RH is quite average for much of the temperate world, indeed it's most definitely not a "high-humidity" environment.

Both Flukecal and NIST specify that in the USA, DC standards labs be < 50% RH. But I think I'll add that to the item description.

[Awesome14]

I asked my Dad where he read the ap note on the LTZ1000, and he didn't remember. He only mentioned it in passing over the telephone when I was working on a LTZ1000 reference. But I did mock up a LTZ1000 reference and push on the IC a bit, and the voltage output changes.
Now, for Lars graphs; Good, solid work. I'm happy to have the info. If the unit was designed to operate at over 50% RH, I'd have a problem. But the standard is designed to be operated in a controlled environment not to exceed 50% RH, and with a temp between 17-26C.

Hello Tom K. (awesome14) - Oooh it was you working on this LTZ1000 reference ... ? We observed this ad with your great soldering artwork on Flebay - "used briefly for a prototype" 

https://www.ebay.com/itm/HP-3458A-Voltage-Reference-Board-REV-A-03458-66509-LTZ1000/263337867308?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D49452%26meid%3Dfa21f476378b41c3b41e43bb691f0928%26pid%3D100675%26rk%3D1%26rkt%3D15%26sd%3D263337867308&_trksid=p2481888.c100675.m4236&_trkparms=pageci%253Af8c65513-cfbf-11e7-8aec-74dbd18045d9%257Cparentrq%253Ae55276b115f0ab6ac789a120fffb06cc%257Ciid%253A1

A true craftsman at work ... 

Relative humidity
Both Fluke (8060A,...) & Keysight (U125XB,...) warrant in their manuals that their handheld DMMs function at a relative humidity up to 80% ... so probably your toys were addressing the market of the high end DMMs such as 8508 - 3458A - 1281 and alike ?

Well, I didn't solder on the board. I just dropped it onto some pins.

[Awesome14]

OK, I thought perhaps I could appeal to the civilized side of the members on this board, but there doesn't seem to be one. I've seen bad manners and quarrelsome individuals, but nothing close to what I've witnessed on this board.

I'm embarrassed for you. I don't know how anyone can get along in life with such a rude demeanor. It's utterly pathetic. But, it will keep you down where you belong and make more room for civilized people at the top.

One thing I find universal among fools: they are to the mechanism of cooperation what sand is to the mechanism of a watch. Didn't anyone teach you people how to behave?

It is no reflection of me what occurred in this thread. You have no idea who it is that you criticize. I suffered warrantless accusations of lying, without a shed of proof! Fools realize the truth after it's too late. And the thing is, you people go out of your way to create trouble for me!

Because of that, and because you couldn't be content abusing just me, and because no amount of sound instruction has proven sufficient to correct your behavior, I turn you over to the one you failed. Hopefully your souls can be saved through abject adversity. But I think it will just kill most of you.

You've failed! I gave you enough rope to hang yourselves, and you did. May God have mercy on you.

[beanflying]

Keep on going your imaginary friend will keep you making your pseudo science speak a reality if you believe and wish hard enough.

If you overstate manufacturers claims and accuracy specifications you need to back it up with FACT and LOCIC and not BABBLE!

BTW how many other accounts do you run here or on other forums

[Echo88]

Can we please close this thread and not feed this troll anymore?

[MK]

Item does not meet spec, end of story, lets close this one

[bopcph]

Here is two screen shoots from excel with about two years of measurements of two D-105, two SVR-T and one VREF10. As reference I have an REF102CM (metal case) with temperature compensation that has been powered for 17 years. The VREF10 is compensated with the value 1.3ppm/C I got from the manufacturer. The others are not compensated. The room temperature has varied between 19 and 29 °C.

In the beginning I did a humidity test as can be seen in the graphs. Both D-105 and SVR874 were in a box with a large amount of silica gel prepared to get about 80-85%RH. As can be seen from the quick drop the box was not very tight. The VREF10 was in a plastic bag with a silica gel bag.

The D-105 and SVR874 were continuously powered about the first year. The last year it has been in a shelf in a box between measurements so now with a humidity of 35%RH in the room but above 50%RH most of the last two months the references probably have acquired humidity. This can be clearly seen on the D-105's as they dropped about 5ppm the last week when powered in the about 35%RH environment.

The VREF10 has only been powered about 15 minutes at every measurements. The original batteries are still ok!

Lars

If you give that REF102C a stable environment it ani't that bad, isn't it !?
Look at Lars' nice graphs and compensate for the humidity its actually quite nice considering a price tag of 1/20th of a LTZ1000A 

Thanks Lars 

[Awesome14]

OK, everyone, thanks for all the help.