fuse blown indicator on multimeters? - Page 1
Forum section: electronics / beginners

author: ledtester
author_rank: Super Contributor
timestamp: June 13, 2018, 02:25:49 pm
content: I just junked a couple of power supplies because I thought they weren't any good.Then I discovered that my multimeter fuse was blown.So that got me to wondering if any multimeters sport an indicator that your fuse used for current measurements is blown. I haven't noticed such a feature on any meters, so perhaps there is reason for it?

author: helius
author_rank: Super Contributor
timestamp: June 13, 2018, 03:59:00 pm
content: I have some with an indication, some without. When provided, it is sometimes combined with the probe detection feature.So if either the fuse is blown, or the + probe is not in the correct mA or A socket, an error indication and tone appear when the meter is set to mA or A.If the probe detection also works the other way, i.e. an error indication if the + probe is in an amps socket with the meter set to a different mode, it can give warning before the user makes a connection mistake that might blow the fuse.These probe detection features rely on a split pin inside the amps sockets, so they work even before you connect to the circuit under test.

author: Mr. Scram
author_rank: Super Contributor
timestamp: June 13, 2018, 04:09:08 pm
content: A second multimeter would do the job. Any time an unexpected result turns up on a number of units you should be wary of the equipment you're testing with. In my experience you should be anyway, as even the best stuff breaks and does odd things. Or sometimes it's simply a wrong assumption or piece of knowledge that trips you up.

author: TomS_
author_rank: Frequent Contributor
timestamp: June 13, 2018, 04:16:11 pm
content: Quote from: Mr. Scram on June 13, 2018, 04:09:08 pmUnless you do the same silly thing and blow the fuse in both of your meters leading to the same unexpected result.

author: tpowell1830
author_rank: Frequent Contributor
timestamp: June 13, 2018, 04:23:40 pm
content: Training... experience...Hope this helps...

author: Mr. Scram
author_rank: Super Contributor
timestamp: June 13, 2018, 04:30:15 pm
content: Quote from: TomS_ on June 13, 2018, 04:16:11 pmAt least you can use the second DMM to measure the condition of the fuses of the first. I'm not going to say I've been there, because that would be embarrassing.By the way, the answer to that is having a third DMM. Now you now why they say you can never have enough DMMs.

author: Shock
author_rank: Super Contributor
timestamp: June 13, 2018, 04:53:17 pm
content: You normally don't need a second meter, it's as simple as this.

author: Mr. Scram
author_rank: Super Contributor
timestamp: June 13, 2018, 05:19:15 pm
content: Quote from: Shock on June 13, 2018, 04:53:17 pmHere too it pays to double check what you see.Man it's painful to see the lad poking the sides of the socket repeatedly.

author: Shock
author_rank: Super Contributor
timestamp: June 13, 2018, 08:39:12 pm
content: Quote from: Mr. Scram on June 13, 2018, 05:19:15 pmPlease explain what you are talking about, what needs double checking?He is poking to find the hole because he is standing off camera and pointing the probe upwards to avoid triggering the socket alert which is on the bottom side of the socket.

author: Mr. Scram
author_rank: Super Contributor
timestamp: June 14, 2018, 01:23:42 am
content: Quote from: Shock on June 13, 2018, 08:39:12 pmUsing two methods to measure a blown fuse. Check, check and double check. Never trust a thing you see. Even if just to save you from tearing an 87V apart when it's not needed.

author: Shock
author_rank: Super Contributor
timestamp: June 14, 2018, 03:39:09 am
content: Quote from: Mr. Scram on June 14, 2018, 01:23:42 amGet 3 multimeters to test a fuse you suspect is bad, check 4 times and don't trust anything you see. Gotcha.