Teardown: Voltage Standards - Page 1
Forum section: electronics / general

author: zlymex
author_rank: Frequent Contributor
timestamp: March 24, 2016, 03:33:00 pm
content: Summary before teardown- The years of release and stop are estimate. Correct me if anyone know the accurate.- Oven: small dot for chip level, large for board level- There are evidents indicating that the voltage of most LTZ1000 and LTFLU-1 go down with time while SZA263 go up.- The order of the teardown is roughly chronological- The order on the list is according to the annual drift(and the time of release of same)- The teardown will focus to the most important part: the 7V reference and the 7V to 10V conversion.- Of course I don't have the teardowns of all listed(the list is not complete on its own). If anyone has, contribute.- There is no release of new voltage standard for sometimes now, until recently by ADCMT, 'The highest performance 6900 in the world':http://www.adcmt.com/news/press/press-2015/press20150624.htmlFluke 731AOne of the basic circuit.If delete R3 and R4, connect neg input of the opamp to base of the refamp, then we get the simplest refamp circuit.Fluke 731BThere are three major modifications compare to 731A- output current limiting circuitry added- use hermetic WW. Those WW became widely used by Fluke later- use SZA263 as refamp. This refamp became widely used by Fluke laterFluke 732A(See attachment)There are some modifications compare to 731B- board ovenized.- use lead-acid batteries instead of NiCad.- small-sized hermetic WW were used- refamp protected by Q5(for later version of LTFLU-1, the protection is build-in)- formalize the output as 'series pass'- use 'binary' scheme on major part of the 10V adjustment, but not all.The basic circuitry is not changed even for the designator

author: zlymex
author_rank: Frequent Contributor
timestamp: March 24, 2016, 03:34:34 pm
content: Guildline 4400Datron/Wavetek 4910see attachment

author: zlymex
author_rank: Frequent Contributor
timestamp: March 24, 2016, 03:36:00 pm
content: 4910 continuedFluke 732BThere are some modifications compare to 732A- more compact- battery: one 12V instead of four 6VThe crucial components unchanged. Those pair of hermetic WW contribute to most of the drift and there are many knock out 732B units because it.

author: alanambrose
author_rank: Frequent Contributor
timestamp: March 24, 2016, 04:54:58 pm
content: Very nice, thanks for putting in all the workAlan

author: zlymex
author_rank: Frequent Contributor
timestamp: March 24, 2016, 04:56:20 pm
content: Datron/Wavetek/Fluke 7001A lot of new technology used in it:- Low chip temperature to minimize drift- Taitanium-Nitrate(TaN) "statistical" resistor arrays- 8 bit DACs to adjust 10V- NiMH battery(10 AA)- Patented Hysteresis Safeguard- Patented high-isolation DC/DC Converter- Electronic(rather than electromechanical) switches were usedA practical approach to maintaining DC reference standardswww.elcal.ch/files/11749-eng-01-a.pdfStrange enough, the teardown revealed that they use TDP1603 resistor array, the material Passivated nichrome instead of TaN.www.vishay.com/docs/60045/tdp.pdf(The End)

author: quarks
author_rank: Frequent Contributor
timestamp: March 24, 2016, 06:07:40 pm
content: Bookmark

author: dr.diesel
author_rank: Super Contributor
timestamp: March 24, 2016, 06:11:32 pm
content: Most excellent

author: lowimpedance
author_rank: Super Contributor
timestamp: April 04, 2016, 12:22:04 pm
content: @ ZlymexDont know how I missed this thread, but most excellent as usual.As for the Guildline 4400 It is also the same as the Statronics VS4 which was from a design developed at CSIRO.I have a prototype and a VS4 (now operational again), will post some pics tomorrow.

author: Vgkid
author_rank: Super Contributor
timestamp: April 04, 2016, 10:41:42 pm
content: On a related note, does snyone have any information on the koep transportable standards. I bought one on ebay, and it was stolen from the guys store.

author: ManateeMafia
author_rank: Frequent Contributor
timestamp: April 05, 2016, 12:44:25 am
content: I have a little info on the Koep standards. Attached are a couple of photos, I have the triple reference. Sorry, I need to take more pictures of mine and put them on xDevs. I have a few of the internal construction but each reference is potted.There is also a datasheet for their zeners presumably the best were used in the standards.I also have a scanned copy of the VTS4007 manual but it is too large to fit here but I will upload it to ko4bb.Of note, the only one I know of that is in use is at IET labs. It is listed under their scope of accreditation.http://www.a2la.org/scopepdf/2073-01.pdf

author: lowimpedance
author_rank: Super Contributor
timestamp: April 05, 2016, 01:59:06 am
content: Quote from: lowimpedance on April 04, 2016, 12:22:04 pmOkay here are the photos of the VS4 and the NML01 prototype.I see it looks like the Guildline version does not have the 1.018V outputs ?The oven runs at approx 33 deg C. The heating 'elements' are the LM395

author: zlymex
author_rank: Frequent Contributor
timestamp: April 05, 2016, 06:17:35 am
content: @lowimpedance Very nice photo. Guildline also has the similar version called 4410, must be the same origin.

author: lowimpedance
author_rank: Super Contributor
timestamp: April 05, 2016, 06:55:07 am
content: Quote from: zlymex on April 05, 2016, 06:17:35 amI was not aware of the Guildline versions, most interesting.Forgot to mention the prototype only used 6 lm329s not the 8 as in the 'production units', also the precision card resistors were made by ESI iirc.

author: manganin
author_rank: Regular Contributor
timestamp: April 05, 2016, 09:20:46 am
content: Quote from: lowimpedance on April 05, 2016, 06:55:07 amQuote from: lowimpedance on April 05, 2016, 01:59:06 amThere were two versions manufactured by Statronics in Australia, but distributed under the Guildline brand. The 4410 with 1.018V outputs and the economy 4400 without. The 4400 was identical to the 4410 except the front panel and the zener buffer op-amps and the 1V dividers not assembled on the printed circuit board.Quote from: lowimpedance on April 05, 2016, 01:59:06 amYour VS4 is the late version with the Guildline face lift (note the "grid" on the right side of the front panel), but Statronics branded. The original Statronics was not as pretty, see the photo attached.

author: MegaVolt
author_rank: Frequent Contributor
timestamp: March 23, 2020, 12:52:10 pm
content: A little bit of beauty 732A