Teardown : ESI DB52 resistance decade check - Page 1
Forum section: electronics / testgear

author: TiN
author_rank: Super Contributor
timestamp: April 14, 2015, 05:46:53 pm
content: RAWR, precision-nuts.Since I got 60% (3 from 5) of my 2001 meters repaired and ready for calibration, its time to get some resistance box. And as I already have some foils in main values, addition of more fine decade resistor was wanted.I had no intention to spend big money, it is also my first ever decade box, so end up winning this ESI 5-decade resistor for a 95$ excluding shipping. Seller state it was good and calibrated January 2013.It is dirty and little rusty outside, but that is fine if the thing performs well.Don't turn it on, take it apaaartThat is well and robust construction, but switches are not as fancy as in higher grade decades, which I saw on web review before.There are no trimpots or jumpers elsewhere, how does such resistance decades are usually calibrated?

author: TiN
author_rank: Super Contributor
timestamp: April 14, 2015, 05:52:43 pm
content: Performance and verificationI had two meters to check this DB52 :Agilent 34970A with 34901A mux card, in 4W ohms mode, 200NPLC (Calibrated in 2013)Keithley 2001 , 4W ohms with offset compensation, 10NPLC (Calibrated February 2014).Not to jam thread with gazillion of photos, here are thumbnails.First connect meter 4W to ESI decade. Set all decades to zero.Null meter using offset(relative) function. This will be our zero reference.Adjust decades, measure resistance.I am impressed as for it's money. Definately a keeper unit.Will use this box for KX project circuits tests, such as ADC, DACs and current sources.

author: TiN
author_rank: Super Contributor
timestamp: April 14, 2015, 05:53:37 pm
content: Measured accuracy for all decades (by 34970A)--1E11E21E31E41E5000.00007 Ohm0.00007 Ohm0.00038 Ohm0.02559 Ohm1.93515 Ohm0110.00067 Ohm99.99229 Ohm999.93156 Ohm9999.91797 Ohm100001.12500 Ohm0219.99982 Ohm200.00353 Ohm1999.89009 Ohm19999.94097 Ohm200016.91667 Ohm0329.99740 Ohm300.00983 Ohm2999.82813 Ohm30000.11719 Ohm300011.90625 Ohm0440.00387 Ohm400.01471 Ohm3999.79818 Ohm40000.22656 Ohm400014.12500 Ohm0549.99859 Ohm500.02953 Ohm4999.77409 Ohm50000.20313 Ohm500017.66667 Ohm0659.99515 Ohm600.03055 Ohm5999.70898 Ohm59999.72396 Ohm600026.75000 Ohm0769.99643 Ohm700.03494 Ohm6999.64355 Ohm70000.16667 Ohm700028.00000 Ohm0879.99512 Ohm800.04053 Ohm7999.60482 Ohm80000.16667 Ohm800028.50000 Ohm0989.99380 Ohm900.04500 Ohm8999.57552 Ohm90000.13542 Ohm900032.16667 Ohm1099.99229 Ohm999.93156 Ohm9999.91797 Ohm100001.12500 Ohm1000029.60000 Ohm--1E11E21E31E41E500Invalid dataInvalid dataInvalid dataInvalid dataInvalid data0167.043 ppm-77.133 ppm-68.420 ppm-8.203 ppm11.250 ppm02-8.965 ppm17.624 ppm-54.932 ppm-2.930 ppm84.609 ppm03-86.594 ppm32.756 ppm-57.292 ppm3.906 ppm39.688 ppm0496.703 ppm36.774 ppm-50.476 ppm5.664 ppm35.313 ppm05-28.305 ppm59.082 ppm-45.215 ppm4.063 ppm35.313 ppm06-80.808 ppm50.964 ppm-48.503 ppm-4.622 ppm44.583 ppm07-51.008 ppm49.874 ppm-50.921 ppm2.344 ppm40.000 ppm08-61.035 ppm50.659 ppm-49.377 ppm2.051 ppm35.625 ppm09-68.834 ppm49.981 ppm-47.201 ppm1.476 ppm35.764 ppm10-77.133 ppm-68.420 ppm-8.203 ppm11.250 ppm29.625 ppmAttached dirty spaghetti code to calculate ppm table from raw data samples.

author: Vgkid
author_rank: Super Contributor
timestamp: April 14, 2015, 06:43:16 pm
content: Nice score, I picked up a DB62 last year for 80tot, and a DB655 for 30tot(still need to put it back together).I noticed my DB62 is pretty stable, my favorite test is to set all dials to '2', and my 3456 reads '222,225' though sometimes it reads 222,222

author: TiN
author_rank: Super Contributor
timestamp: April 15, 2015, 04:57:14 am
content: Added decade tolerance data in third post, based on 34970A measurements.Don't shoot for code.