USA calibration club

[Vgkid]

Yeah, that's significantly different from the older ones I'm accustomed to seeing. Wow, good to know.

It looks like things went even further downhill once IET took over.  https://www.eevblog.com/forum/metrology/teardown-standard-resistors/msg1295900/#msg1295900

That is how the ESI DB-62 is set up.

[cellularmitosis]

I'm curious-- Why don't you just repair this decade box, and add knobs? -- This could be a transfer standard as well-- just get someone with good equipment (3458A or better) to calibrate each value.

So the honest answer is that I'm just having fun    but if I had to justify it, I'd say that by the time I spend money on a few replacement switches (I've already tried some silicone spray and it didn't help), on knobs, etc, I'd just have another decade box, which I already have two of.  Plus, by hacking this into transfer standards, this opens up the possibility of trying to improve the performance, e.g. encasing in silicone oil, possibly adding a 25C heater, perhaps even a copper tempco-compensation resistor (if the tempco's turn out to be negative).

[bitseeker]

Yeah, though it's probably still better than the little IET RC box I have with the thumbwheel switches.

[nikonoid]

I have a garbage condition 1433. It has few good switches with very low and stable contact resistance. CM, I can easily donate a switch.
Now we can fit it with just 4 binding posts to limit the need for expensive low emf posts.

This decade has 11 positions and each of them can be wired individually with a different resistor going directly to common. This can give us these values from the same box:

10ohm, 20, 100, 200, 1k, 2k, 10k, 20k, 100k, 200k, and 1M.

This sequence covers full range on most meters and also allows us to check linearity of a meter, by having known non full scale values.

I also have some resistors from 1433. Tempco of these resistors is not the best, but not horrible also.

Another thing to consider is that 1433 switch has 4 individual wiper blades. If we can separate them as 2 and 2 we can bring 4 terminal kelvin connections right to the contact, eliminating contact resistance at all.

This would be fairly compact and light traveling 4 terminal resistance standard covering much of a useful range.

Is this something you would want to try? I have a milling machine and can help with making precision holes in a casing.

[cellularmitosis]

Sorry mate, definitely appreciate the offer, but I have already sacrificed her in the name of science

https://www.eevblog.com/forum/metrology/t-c-measurements-on-precision-resistors/msg1449156/#msg1449156

Tempco of these resistors appears to be in the neighborhood of -5 to -6ppm/C, so its not ideal for a transfer standard anyway (unless we tried to ovenize the whole thing which is an interesting idea...    )

[cellularmitosis]

This is ideal for our desired 1, 2, 3-value transfer standards, as we can simply parallel 2 of the 2-values to make a 1-value, then put that in series with the other 2-value to make 1, 2, and 3.

Edwin Pettis was kind enough to point out that there are many meters which call for e.g. 1.9x values for Ohms calibration, and that I'd probably want the value to be just under the 1x, 2x, 3x nominal values for maximum compatibility.  He inspired me to start digging into the service manuals of a bunch of meters and figure out what they require.

I've started working on a few tables with this info and other general info about meters which hobbyist volt-nuts are likely to have: https://github.com/USACalClub/gear/blob/master/dmms/README.md

If you have a meter you'd like me to add to this growing list, give me a shout, especially if you have a meter which has possibly problematic calibration requirements (e.g., it looks like the Keithley 192 had no "over-range" ability -- its max reading was 1.999999, so a transfer standard sitting at 2.000123 wouldn't work).

[bitseeker]

Nice tables, CM! I thought the K199 was 5.5 digits. Oh, I see you have it in both sections.

Is the HP 3458A pending?

[cellularmitosis]

Nice tables, CM! I thought the K199 was 5.5 digits. Oh, I see you have it in both sections.

Is the HP 3458A pending?

Oops, thanks!

Yeah, this table grows a bit haphazardly, as finding info out about one meter leads to discovering another.  By the time I started adding a 8.5-digit section, I realized I was a bit off-track from filling out the 6.5-digit section

Edit: oh yeah, and I remembered that someone created a similar table here on the forum with details about all of the 8.5-digit meters.  I should link to that for starters.

[bitseeker]

Links to additional reference materials are certainly welcome. There's also the DMM comparison spreadsheet thread. Although not specifically targeting metrology, it has a lot of good feature info.

[SirAlucard]

Nice tables, CM! I thought the K199 was 5.5 digits. Oh, I see you have it in both sections.

Is the HP 3458A pending?

Oops, thanks!

Yeah, this table grows a bit haphazardly, as finding info out about one meter leads to discovering another.  By the time I started adding a 8.5-digit section, I realized I was a bit off-track from filling out the 6.5-digit section

I was going to say isn't there already a pretty extensive list of DMMs, which include handhelds as well as bench DMMs. In fact wouldn't this list suffice? https://www.eevblog.com/forum/testgear/multimeter-spreadsheet/

I mean I suppose your listing is different, and it is nice to see what they look like.
Edit: oh yeah, and I remembered that someone created a similar table here on the forum with details about all of the 8.5-digit meters.  I should link to that for starters.

[kj7e]

Just in case any one here needs a bench DMM upgrade for cheap;
https://www.ebay.com/itm/HP-AGILENT-KEYSIGHT-3456A-DIGITAL-VOLTMETER/253463397941?_trkparms=pageci%3A9afa0f65-27d0-11e8-9345-74dbd1808459%7Cparentrq%3A2676f9851620a8608e4b4673fff982b5%7Ciid%3A1&_trksid=p2481888.c100651.m4497

[bitseeker]

Maybe. Their listings always start at $9.99 with the balance made up for in the shipping. Due to the low apparent starting price, they tend to get lots of bids that often drive the total cost too high.

[cellularmitosis]

I was going to say isn't there already a pretty extensive list of DMMs, which include handhelds as well as bench DMMs. In fact wouldn't this list suffice? https://www.eevblog.com/forum/testgear/multimeter-spreadsheet/

I mean I suppose your listing is different, and it is nice to see what they look like.
Edit: oh yeah, and I remembered that someone created a similar table here on the forum with details about all of the 8.5-digit meters.  I should link to that for starters.

Ah, thanks so much!  I think that spreadsheet only had handhelds when I last saw it.

[SirAlucard]

I was going to say isn't there already a pretty extensive list of DMMs, which include handhelds as well as bench DMMs. In fact wouldn't this list suffice? https://www.eevblog.com/forum/testgear/multimeter-spreadsheet/

I mean I suppose your listing is different, and it is nice to see what they look like.
Edit: oh yeah, and I remembered that someone created a similar table here on the forum with details about all of the 8.5-digit meters.  I should link to that for starters.

Ah, thanks so much!  I think that spreadsheet only had handhelds when I last saw it.

When I went through it I was pretty sure it had bench meters too. It also looks like he includes a separate list of bench and hand held meters.

Maybe. Their listings always start at $9.99 with the balance made up for in the shipping. Due to the low apparent starting price, they tend to get lots of bids that often drive the total cost too high.

Yea those shipping prices are always killer. I always love finding items that are $.99 Buy it now, with $150 shipping. They really shouldn't be allowed to do that. I think that's how they get away with having to pay Ebay's 15% of sale price.

[kj7e]

I see $59 for shipping from Texas to CA, that's not unrealistic for a 3456, its big heavy.  A heck of a good 6.5 digit meter though.  Looks clean and the bid is only $35 (as of now) with less than two days to go. 

[bitseeker]

Yep, definitely a good meter to keep an eye on. Just wanted to be sure folks were aware of the shipping. I've shipped HP 856x and 859x spectrum analyzers across the country for less, but anyway, YMMV.

[orin]

So has anyone worked out how they got it to display "+ 500000" with the SHIFT and EXT TRIGGER LEDs lit?

[Vgkid]

I'm going to bed ( and on my phone) , but it might be one of the error codes.

[bitseeker]

So has anyone worked out how they got it to display "+ 500000" with the SHIFT and EXT TRIGGER LEDs lit?

Shift + ~V = AC+DC volt mode. It's supposedly measuring some kind of voltage in auto-ranging mode via external trigger, but I'm not sure what the 500000 is indicating since there's no decimal point displayed.

For self-testing, a negative number on the display indicates the self-test number (1–12) that failed. The AC converter is test 12.

[orin]

So has anyone worked out how they got it to display "+ 500000" with the SHIFT and EXT TRIGGER LEDs lit?

Shift + ~V = AC+DC volt mode. It's supposedly measuring some kind of voltage in auto-ranging mode via external trigger, but I'm not sure what the 500000 is indicating since there's no decimal point displayed.

For self-testing, a negative number on the display indicates the self-test number (1–12) that failed. The AC converter is test 12.

I'll have to dig one of mine out and see if I can make it display that - perhaps setting one of the registers?  If not, I'd be expecting to have to do repair work on this unit.

[kj7e]

So has anyone worked out how they got it to display "+ 500000" with the SHIFT and EXT TRIGGER LEDs lit?

Shift + ~V = AC+DC volt mode. It's supposedly measuring some kind of voltage in auto-ranging mode via external trigger, but I'm not sure what the 500000 is indicating since there's no decimal point displayed.

For self-testing, a negative number on the display indicates the self-test number (1–12) that failed. The AC converter is test 12.

I'll have to dig one of mine out and see if I can make it display that - perhaps setting one of the registers?  If not, I'd be expecting to have to do repair work on this unit.

Your close, I just played with mine, all you have to do is enter 500000 and not store it, the display will show +500000 with out a decimal.  Since there is no input to the unit, I suspect he is just trying to show a displayed value.  I see nothing to indicate there is a fault and it is listed a guaranteed with returns accepted.

[bitseeker]

How peculiar (showing that instead of a measurement). Thanks for solving the mystery, kj7e.

[RandallMcRee]

Is anybody here bidding on this?  I'm thinking of it, but I won't if anyone else is...

My way is always to put in a bid in the last two seconds. I think the current bidders aren't following this forum's ebay bidding thread 

[bitseeker]

Yeah, most eBay bidders don't know how to bid properly. C'est la vie.

I'm not bidding on that listing, so no worries here.

[orin]

Is anybody here bidding on this?  I'm thinking of it, but I won't if anyone else is...

Not me.