Any fix for User Calibration Failed error on Keysight 3000X DSO? - Page 1
Forum section: electronics / testgear

author: TK
author_rank: Super Contributor
timestamp: April 06, 2017, 04:33:17 pm
content: Hi, I just purchased a DSOX3014A that fails User Calibration. Is there any way to go back to the previous calibration status? Factory Default does not make the error message to go away.Thanks

author: TheSteve
author_rank: Unknown
timestamp: April 06, 2017, 05:03:37 pm
content: Not that I am aware of. You'll probably want to connect to the uart to see what step it fails on. Unless it's under warranty of course.

author: TK
author_rank: Super Contributor
timestamp: April 06, 2017, 05:23:06 pm
content: Unfortunately it is out of warranty

author: TheSteve
author_rank: Unknown
timestamp: April 06, 2017, 06:24:38 pm
content: Sounds like a fun project. Do all channels appear to work?

author: LA7SJA
author_rank: Regular Contributor
timestamp: April 06, 2017, 06:35:56 pm
content: Have you checked the cables used to calibrate?Johan-Fredrik

author: TK
author_rank: Super Contributor
timestamp: April 06, 2017, 07:47:41 pm
content: Quote from: TheSteve on April 06, 2017, 06:24:38 pmEverything was working fine, but decided to upgrade firmware and run user calibration. It is still working fine, except for AutoSet that gives an error that instrument is uncalibrated... and the annoying message when the scope is turned on.

author: TK
author_rank: Super Contributor
timestamp: April 06, 2017, 07:51:14 pm
content: Quote from: LA7SJA on April 06, 2017, 06:35:56 pmYes, I assembled the fixture as recommended in Service Guide (except for one of the BNC wire that is of different length). If the calibration setup is incorrect, it stops with a warning message. With the calibration fixture, it starts calibration and then it makes a lot of relay noises and stops with the error, right at the beginning of the process.

author: LA7SJA
author_rank: Regular Contributor
timestamp: April 06, 2017, 08:06:15 pm
content: Have you tried to perform hardware self test?Pressing  > Service > Hardware Sel f Test performs a series of internalprocedures to verify that the oscilloscope is operating properly.Johan-Fredrik

author: TheSteve
author_rank: Unknown
timestamp: April 06, 2017, 08:17:41 pm
content: I though maybe you bought it in that condition for a good price etc, if you bought it and then it failed that really sucks.You replied that all channels work but have you verified all 4 channels work over there entire range, with and without 50 ohm termination enabled - and that they measure 50 ohms?If it stops near the beginning of the process it seems like it is failing something major.

author: nctnico
author_rank: Super Contributor
timestamp: April 06, 2017, 08:21:07 pm
content: I'd start by checking all the BNC cables first and then all ranges of all channels. It wouldn't surprise me if it turns out to be one of the BNC cables which is flaky.

author: TK
author_rank: Super Contributor
timestamp: April 06, 2017, 08:36:27 pm
content: Quote from: LA7SJA on April 06, 2017, 08:06:15 pmI performed Hardware self test and it passes

author: Keysight DanielBogdanoff
author_rank: Unknown
timestamp: April 06, 2017, 08:37:45 pm
content: I'd also make sure all your BNC cables are the same length, just to be sure it's not causing any issues.

author: LA7SJA
author_rank: Regular Contributor
timestamp: April 06, 2017, 08:51:30 pm
content: If you insert a pulse like the probe cal. signal to the "trigger" cable end of the "User Calibration cable" you can check that the 4 ch. are on the same level and phase by comparing the 4 ch. (short timebase).Johan-Fredrik

author: TK
author_rank: Super Contributor
timestamp: April 06, 2017, 08:59:07 pm
content: Thank you all for the help and suggestions. I will try with a new set of cables as I am not very confident that all of them are 50 ohms and definitely they are not the same length.

author: LA7SJA
author_rank: Regular Contributor
timestamp: April 06, 2017, 09:25:28 pm
content: Use 50W RG58AU or equivalent BNC cables, the short cable < 12 inches (30,48cm) the long < 40 inches (101,60cm). Use the same connectors and RG58AU coax cable (same velocity factor on all cables) for every cable you make and check the assembly according to my last post.PS! Report back when you succeed , thank you in advance.Johan-Fredrik

author: TK
author_rank: Super Contributor
timestamp: April 06, 2017, 10:48:39 pm
content: USER CALIBRATION PASSED!!!!!All suggestions pointed to the same issue: The calibration setup. Thank you ALL for the suggestions and expert opinion. Thank you Daniel, It feels really good to know that the company behind the product is listening.Lessons learned:Used 5 BNC cables, 2 x 12" (CH1, CH2) and 3 x 24" (CH3, CH4, Trigger out). Couldn't measure the phase shift, but measured a delay of 10ns between the signals on the channels with 12" cables and 24" cables. I noticed that at the beginning of the process, the calibration routine activated CH1 and CH3 (sync the 2 ADCs/ASICs?) and it showed some Yellow and Blue traces and it failed. I placed the 12" cables to CH1 and CH3 and the calibration process advanced to more than 50% but failed again (at a different point). So decided to make a new fixture cutting and soldering the BNC cables and it completed the user calibration.I did not think the cable length and quality mattered, but it did. Big time.

author: Keysight DanielBogdanoff
author_rank: Unknown
timestamp: April 06, 2017, 10:51:35 pm
content: Great, glad it worked! You'd be surprised how much of a difference a different length cable will make for calibration stuff.