I don't need no stinking calibration - Page 1
Forum section: electronics / testgear

author: staxquad
author_rank: Frequent Contributor
timestamp: June 13, 2013, 04:30:52 am
content: I don't need no stinking calibration22*C, warm up > 8 hoursPrime Technology - General Resistance DAS-47AL, 7 digit 0 to 1V, 0 to 10V Kelvin Varley Dividerresolution 0.1 micro voltaccuracy 0.0015%T.C. typical 0.7ppm/*C, max 1.5ppm/*Ccan select either HP 3478A, connect the +10V reference and it will not twitch for hours, steady +10.0000VDCmy Fluke 87III shows +9.996VDCshielded Kelvin Varley Divider at the top and reference voltage adjust shielded box at the bottomamplifier zero adjust at the top left cornershielded transformer box

author: ftransform
author_rank: Frequent Contributor
timestamp: June 15, 2013, 11:06:04 am
content: are you working on an moth fart detector?

author: staxquad
author_rank: Frequent Contributor
timestamp: June 15, 2013, 03:41:46 pm
content: Quote from: ftransform on June 15, 2013, 11:06:04 amedit: I'm still trying to figure out what you said. So far, either you are saying the unit is old, or it's sensitive. For old, I hope the unit carries on; for being sensitive, right now I only have confidence in 6 of the digits which only covers my meters, nothing more. Hope to eventually check the unit on a calibrated meter to validate the 7 digits.you don't eat pudding?if you don't like old, you can still get it new, only $8570 (most likely updated circuitry), also constant current but only 6 digitshttp://www.newark.com/shurite-meters/das-56a/das-56a-dial-a-source-general-resistance/dp/73K4753http://www.primetechnology.com/PartsDetails.aspx?PartsId=144&Parentid=59&ParentType=Chttp://www.primetechnology.com/cp/images/PartsDocument/83658.pdfnewer versions a little too rich for my blood at $500 used on ebay

author: codeboy2k
author_rank: Super Contributor
timestamp: June 15, 2013, 11:16:51 pm
content: ok.. now you done it... you made me want to build one

author: staxquad
author_rank: Frequent Contributor
timestamp: June 15, 2013, 11:59:06 pm
content: Quote from: codeboy2k on June 15, 2013, 11:16:51 pmthe pdfs then

author: edavid
author_rank: Super Contributor
timestamp: June 16, 2013, 12:38:03 am
content: Does it buzz as much as my DAS-56A's do? I can't leave them on, they drive me nuts.

author: ltz2000
author_rank: Regular Contributor
timestamp: December 02, 2015, 05:59:16 pm
content: Quote from: edavid on June 16, 2013, 12:38:03 amLast week I helped a friend who also has a loud Dial-A-Source.There is no cure for the sound. The transformer key design parameter seems to be the low capacitive coupling and the quietness comes far behind.Quote from: staxquad on June 15, 2013, 03:41:46 pmDoesn't surprise me at all. A real engineers daydream and assemblers nightmare. A number of small printed circuit boards here and there and maximum amount of wire between them. Full of tiny custom metal boxes and mounting brackets needed to solve the design flaws made in the earlier stage of the process.Quote from: staxquad on June 15, 2013, 03:41:46 pmMost likely not. The one that I tried to cure was built in the late 90s and looks exactly the same. Most of the parts from the 90s, modern looking solder masks etc. But here and there components, like operational amplifiers and transistors, from the early 80s or even late 70s.The electrical safety was horrible. Doll house wire used for the internal mains connections. Which were of course tied together with the sensitive low voltage DC wiring. A live turret pin was so close to the metal enclosure wall that I needed an ohmmeter to see if it makes a connection or not. The gap was too tight for a piece of paper.

author: Vgkid
author_rank: Super Contributor
timestamp: December 02, 2015, 06:22:23 pm
content: Show us the KVD already, that is what we really want to see.

author: ltz2000
author_rank: Regular Contributor
timestamp: December 02, 2015, 06:43:19 pm
content: Quote from: Vgkid on December 02, 2015, 06:22:23 pmNothing special. Thumb wheel switches, ten resistors soldered on each of them. The resistors are good stuff *, General Resistance brand of course.http://www.primetechnology.com/cp/images/PartsDocument/163323.pdf* EDIT: If you don't ask Mr. Pettis.

author: mtdoc
author_rank: Super Contributor
timestamp: December 02, 2015, 06:44:25 pm
content: Very nice. Looks like there's a DAS-46 on ebay right now for $149. No DAS-47 though.We don't need no stinking calibration - Ha! I can't resist:

author: fivefish
author_rank: Frequent Contributor
timestamp: December 02, 2015, 06:53:16 pm
content: OP: Nice.Here's another one.