Keithley 2015 THD - How to get the BUILT-IN self tests, finally! - Page 1
Forum section: electronics / testgear

author: Macbeth
author_rank: Super Contributor
timestamp: May 15, 2019, 11:47:13 pm
content: For years nobody has came up with a reasonable explanation as to why the 2015 only has the KEY and DISP tests but lacks the well documented* K2000 BUILT-IN mode. Keithley and Tek have not been forthcoming with the info when asked either. Everyone outside of Keithley has resigned themselves to no proper testsSome had suggested there was no room in the ROM for the built-in tests due to the THD board. But anyone looking at a ROM dump can see there is plenty of room. A 'strings' dump shows the tests are still in there. But that could just be left-over garbage from K2000 code. What convinced me is that there are 2x TEST menus in the ROM. One with just the TEST: KEY and TEST: DISP and another one with the same strings again but with TEST: BUILT-IN too. Why have 2x menus? What a waste of bytes?So I just spent the evening playing with IDA and to cut a long story short it has been staring us all in the face for some time, it is as simple as...K2015 powered off. Hold the SOURCE button and power on.(The same procedure as documented in the calibration manual for doing a factory cal.)Now press SHIFT and TEST and there isBUILT-INflashing in all it's glory.Sadly my K2015 fails on the same 306.2 and 306.4 errors that I have on my K2000. I know this is not considered a fault by Keithley as long as the meter still meets specs and is probably why they hidden the damn' test after they introduced the 306 bank anywayTime to replace some JFETs...FWIW from my IDA investigation I found that the keyboard/display to mainboard interface appears to be using nothing more fancy than simple serial TTL 9600,8,N,1(* Well documented, except for the bloody 306 tests)ETA: Firmware B17 here.

author: msquared
author_rank: Regular Contributor
timestamp: May 17, 2019, 04:43:41 pm
content: Thanks for digging this up.Worked for me on B09 A02, all tests passed.

author: jpb
author_rank: Super Contributor
timestamp: May 17, 2019, 05:13:44 pm
content: Thanks for the info.I was a little confused by the BIT:AUTO followed by BANK:FULL followed by FAULT:CONT which I thought was a fault until some fiddling around showed that you have options for how many tests you want and what to do on a fault.So mine passed ok.

author: Macbeth
author_rank: Super Contributor
timestamp: May 18, 2019, 01:44:37 am
content: Mine passes OK too on switch on but after about 15 minutes I get the 306 "faults".Earlier firmwares do not have the 306 tests which are looking for excessive pA input bias currents (ie. the >10G ohm impedance is closer to 10G than 100G+) I think the fault is triggered when the input is under 33G ohm. But I'm just going on the meters 306.1,2 reported values and I don't have a picoammeter.

author: minsik
author_rank: Contributor
timestamp: October 30, 2024, 01:59:20 am
content: New for me (s/h) owner of a Keithley 2015 THD.I can perform the inbuilt self test routine. Power up holding source firstly.Fails (are well documented) 306.2 and 306.4 and 500.1, 500.2.Shift button does reveal the text description of the item failing, but I cant get an actual reading of the error amount like the K2000. (just for interest really)Any clues how to display the actual reading on the 2015 THD?Also discovered one new link on the display pcb to increase VFD drive current, which was not advised on purchase. Let the byer beware! Seems the VFD is on the end section of its life. However that does not concern me too much. I will try for a replacement DD-52 but not hopeful from TEK.Otherwise amazing multimeter. Internal sine wave generator seems much better than the spec if measured by the internal THD. Spec is only .05% and yet measures .002% 1khz, 1V