Issues with the Agilent U1253A meter, can someone else check their unit? - Page 1
Forum section: electronics / general

author: toli
author_rank: Frequent Contributor
timestamp: November 18, 2011, 08:26:03 am
content: Hello everyone,I've bought the U1253A at the Grainger sale, and over time noticed a few issues with the meter. I'veposted it on the Agilent forum, and after a looooooong wait they've finally posted a reply saying the problem is with my unit (at least with one of these issues).The 2 main issues are the following:1- Measuring very small capacitance (tens of pF's - like 33pF) takes about 30second for the reading to settle on the right value.2- Measuring output ripple of PS's is affected significantly by the intensity of the display. It happened on my bench PS (Horizon DHR 40-1), on my sigma11 (www.amb.org), and the regulator I've designed (ToliReg). The reading is about 0.6-0.7mV with the display at max or half of that, but dropping the intensity to the third and lowest setting causes the reading to drop down to 0.4mV. I've measured one of the PS's at work with the Kithely 2010 bench DMM and it reads 0.4mV. It can't be directly compared since they also have a very different BW.Can someone else check these issues and let me know if its the same with their unit as well?

author: hacklordsniper
author_rank: Frequent Contributor
timestamp: November 18, 2011, 08:57:40 am
content: If you have warranty on it try to replace it. In my opinion Agilent is one pretty crappy manufacturer, look the last Dave-s video about measuring resistors and he could not read the data anymore with PC. Agilent should leave multimeters to kiddies that know their work.

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: November 18, 2011, 09:10:10 am
content: toli what test leads did you use for the capacitance measurements ?

author: ejeffrey
author_rank: Super Contributor
timestamp: November 18, 2011, 09:52:29 am
content: Quote from: toli on November 18, 2011, 08:26:03 amI have tested two separate units, and they both display this problem. I believe it is a design flaw with their capacitance measurement.

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: November 18, 2011, 09:55:47 am
content: About pF measurements, this link will probably help.https://www.eevblog.com/forum/index.php?topic=5143.0

author: ejeffrey
author_rank: Super Contributor
timestamp: November 18, 2011, 10:10:29 am
content: No it won't. The 1253A meter has a flawed capacitance function that takes 10s of seconds to respond when the capacitance is < 100 pF. This is even true with no leads at all. I have tested several other meters with exactly the same setup and they don't display this problem. I found one other meter that had the same problem, but I don't remember which brand.

author: PetrosA
author_rank: Frequent Contributor
timestamp: November 18, 2011, 01:29:14 pm
content: Have you contacted their tech support per the recommendation? My experience with Agilent has been that they are very helpful and are willing to find solutions with customers. I would dig a little deeper to find the right channel especially considering that this is a $450 meter, not their $99 fieldwork special. If there is a problem with your unit, it's best to get it figured out and let them get a new one to you.I would also recommend that you write a very clear, detailed description of your test setup so that they (and others) can reproduce it. Use video if need be.

author: toli
author_rank: Frequent Contributor
timestamp: November 18, 2011, 07:17:04 pm
content: I've looked around their web-site and couldn't find the online support, lots of FAQ's, but no real supportCan someone help me find the right channel of support?The capacitance isn't something that's limited to my meter, I read it some where else as well. Regarding the main issue I'm not sure what's the cause and if it's just my unit. I've used the leads that are shipped with the meter, and other than that there's not much to tell actually. PS->DMM directly.Edit: I've sent a support request using the form on Agilent's web-site, I assume it'll be forwarded to the local branch here in Israel (which I'm not sure will be able to help as the meter was purchased in the US). If anyone knows of a different contact at Agilent who could help, please let me know.

author: PetrosA
author_rank: Frequent Contributor
timestamp: November 19, 2011, 12:45:11 am
content: Found this, maybe it will help:Repair & CalibrationFor general service enquiries or to arrange for a repair or calibration of your equipment.phone: +972 3 9288 600fax: +972 3 9288 601hours:08:00 - 17:00 , Sun - Thuaddress:Agilent Technologies Israel Ltd.Azorim Business Park,Dekel building-Floor 7th94 Em-Hamoshavot Road, Kiryat Arie49527 Petach-TikvaIsrael

author: toli
author_rank: Frequent Contributor
timestamp: November 19, 2011, 06:27:19 am
content: I think these are the guys I've emailed

author: saturation
author_rank: Super Contributor
timestamp: November 19, 2011, 12:57:37 pm
content: Just for info, I have the similar performing 1252a, which is just an LCD, which works fine in all modes and does not have the issues Toli raised. Its a stellar DMM.Quote from: toli on November 18, 2011, 08:26:03 am

author: toli
author_rank: Frequent Contributor
timestamp: November 20, 2011, 06:53:03 am
content: Quote from: PetrosA on November 19, 2011, 12:45:11 amJust gave them a call. Turns out the meter is under warranty until December 2012, and the warranty is worldwide so Agilent Israel can take care of it. They said I should send the meter to them explaining the issue and they'll test it. The representative also said that usually with these type of meters they simply replace the unit instead of repairing it.So once I get back home I'll send it over to Agilent, and hopefully they'll be able to solve the issue.

author: PetrosA
author_rank: Frequent Contributor
timestamp: November 20, 2011, 06:08:54 pm
content: That's good news about the international warranty. Sounds like you're on the road to a fixMazel tov!

author: toli
author_rank: Frequent Contributor
timestamp: November 20, 2011, 06:09:54 pm
content: I sure hope so

author: toli
author_rank: Frequent Contributor
timestamp: December 08, 2011, 08:48:02 am
content: Got an initial reply from the local Agilent branch, at the moment no good news. According to their technician the problems aren't really technical problems, as the specs are for full range and not for such low values. However he said he'll try and contact the Agilest support abroad to verify the issue is widespread and not limited to my unit only.I've posted once again on the Agilent forum (with some videos as well). I'll update once I know what's the verdict.Hopefully they'll be able to solve the issue. I can understand why a meter won't be able to measure 500uV riding a DC signal, but 40 seconds to measure caps and 40 second to go back down to zero seems too much, especially from such an expensive meter. What's even stranger is that if I measure a larger cap (say 100nF) and right after that (a few seconds apart) measure the same 33pF cap as in the video it reads the right value in an instant

author: PetrosA
author_rank: Frequent Contributor
timestamp: December 08, 2011, 12:41:40 pm
content: I get a similar response on AC voltage measurements with my U1211A clamp meter. It can take up to 20 seconds to get a voltage reading from a magnetic transformer (low voltage lighting). I don't really use it much anymore except for measuring current on large cables because of that. I never really pursued getting it checked out because I have other DMMs, but it is definitely annoying.

author: toli
author_rank: Frequent Contributor
timestamp: December 20, 2011, 06:59:08 am
content: An update:I've received the meter back from Agilent. They've informed me there's nothing wrong with the meter and that this problem is widespread for all U125x meters (which according to saturation isn't the case with his unit), and that there nothing else they can do. Obviously not the solution I was hoping forBTW, here are the videos I've posted on the Agilent forum as well:http://dl.dropbox.com/u/37472979/Voltage.3gphttp://dl.dropbox.com/u/37472979/Capacitors.3gp