Blew a fuse in my Agilent DMM... just replace it and it will be fine? - Page 1
Forum section: electronics / general

author: shadewind
author_rank: Frequent Contributor
timestamp: February 28, 2011, 07:16:38 pm
content: Hi,I was careless when measuring and blew the 440 mA fuse in the mA and µA current terminal (it seems, anyway, since it has no continuity and measuring mA and µA no longer works) in my brand new Agilent U1242B DMM. Will it work and measure properly as before if i simply replace the fuse or will it be damaged or need recalibration?

author: hacklordsniper
author_rank: Frequent Contributor
timestamp: February 28, 2011, 07:45:29 pm
content: Quote from: shadewind on February 28, 2011, 07:16:38 pmIn 99.99 % it should

author: shadewind
author_rank: Frequent Contributor
timestamp: February 28, 2011, 08:03:15 pm
content: Work fine or need calibration?Anyway... I imagine it was something like 450 mA. I can't be the first one to blow a fuse in a DMM.

author: Strube09
author_rank: Regular Contributor
timestamp: February 28, 2011, 08:11:08 pm
content: Shade,It should be fine. You only blew the fuse. Replacing the fuse would not need a new calibration as the meter monitors a voltage across the sense resistor (which should have been protected by your fuse) and not the fuse.At least you know the fuse that was in you meter worked correctly... About the only way to really know if a fuse worksStrube

author: Sionyn
author_rank: Frequent Contributor
timestamp: February 28, 2011, 08:19:40 pm
content: agreed its fine

author: PetrosA
author_rank: Frequent Contributor
timestamp: March 01, 2011, 12:24:22 am
content: There might be a test you can do to check the fuses. Look in the service guide which can be downloaded from Agilent's website. For the U1272A it involves using the test lead between the V/Ohm terminal and certain parts of the A and mA terminals.

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: March 01, 2011, 03:05:46 am
content: I bet that you can use the Fluke fuse 440mA in it ...But in any case, let us know what pricing did you find, for the new fuse.And I will agree with the many, no calibration needed for the small fuse.Or even for the large , if the multimeter pass the fuse test ( specific resistor measurement )as PetrosA suggests .

author: Unknown
author_rank: Unknown
timestamp: March 01, 2011, 11:26:38 am
content: Quote from: Kiriakos-GR on March 01, 2011, 03:05:46 amI believe the Agilent specs require a higher interrupt current rating than Fluke, although I'm not sure if this was for the 440mA or the 11A fuse. Pricing directly from Agilent seemed quite reasonable last time this subject came up.Quote from: Kiriakos-GR on March 01, 2011, 03:05:46 amWhen in doubt, check with the manufacturer. Calibration is mostly about covering your ass and having someone else to blame if your measurements turn out wrong, so the validity of calibration is solely determined by the manufacturers specs. If it was my own money, I'd probably do a sanity check with another DMM with similar accuracy (put them in series and feed them with a lab supply), but wouldn't shell out the $$$ for a new calibration unless it failed this check. Calibration isn't usually worth the costs for hobbyists anyway.

author: shadewind
author_rank: Frequent Contributor
timestamp: March 01, 2011, 03:41:31 pm
content: I'll get this fuse:http://se.farnell.com/jsp/search/productdetail.jsp?sku=1827166The stock fuse was from the same manufacturer and had the same markings so I assume this is identical.

author: Kiriakos-GR
author_rank: Super Contributor
timestamp: March 01, 2011, 06:50:19 pm
content: Well this link works better for me , the price is in EURO .And it does not look cheap in my end .http://it.farnell.com/siba/5021006-0-44/fuse-for-dmm-1000vac-dc-10x35-440ma/dp/1827166?Ntt=5021006.0%2C44In any case , get more than just one , and if possible buy a spare, and for the one who is still good.