Brymen BM869s noise on readings  - Page 1
Forum section: electronics / beginners

author: EEreloaded
author_rank: Newbie
timestamp: December 16, 2017, 01:07:00 am
content: Hi there,I just received my new Brymen BM869s and wonder in there is anything wrong with it.It has quite someone noise on the readings in all modes and ranges.It‘s especially annoying when I try to use the min/max. When set to mVolts there can be a MAX of 200 mV just by moving around the probes/leads. I use the ones it came with.Any ideas or remarks on that. Thanks, support appreciated!Kai

author: joeqsmith
author_rank: Super Contributor
timestamp: December 16, 2017, 01:31:47 am
content: To be clear, are you saying you are waving the probes around with them hooked to nothing and you are seeing all sorts of noise?

author: EEreloaded
author_rank: Newbie
timestamp: December 16, 2017, 07:40:58 am
content: Exactly so. Works even in ohms setting. The meter’s reading drops from OL down to 5MOhms in min/Max setting just by waving the probes around. The probes are attached to the meter but open circuit. I wouldn‘t mind capturing a little statics, but when I‘m moving the probes to the DUT and get false readings on the way there is more than a minor issue...Thanks for your replyKai

author: joeqsmith
author_rank: Super Contributor
timestamp: December 16, 2017, 03:44:48 pm
content: I assume with you posting in the beginners area, this may be your first DMM. It's a good choice for an all around general purpose handheld meter. You are not the only one to post about this. This is a pretty big site with a lot of information and this topic comes up from time to time. I just searched "open leads" and this was the eighth one down:https://www.eevblog.com/forum/testgear/why-would-a-working-dmm-read-non-zero-with-no-input-connection/msg1187895/#msg1187895I have a German made Gossen that is not stable with a shorting bar across its inputs if you get anywhere near the meter. Spend some time reading about how to use your new meter and have fun with it.

author: EEreloaded
author_rank: Newbie
timestamp: December 16, 2017, 05:35:04 pm
content: Thanks taking the time to respond. Well, it’s not my first meter, but the first proper one.I assumed that the other gear I got just wasn’t sensitive enough to show such behavior. Anyway, I was quite surprised about the voltage level, fair enough though.But what I did not (and honestly still do not) understand is that the effect happens also in resistance and capacitance mode. I never observed something like that.I will take your advice and just start working with it and get familiar with the behavior. Thanks again!

author: IanB
author_rank: Super Contributor
timestamp: December 16, 2017, 05:42:46 pm
content: If you put it in resistance mode with the probes unconnected the meter in autorange should settle on .OL and stay there.If you put it in capacitance mode with the probes unconnected the meter should settle on 00.00 nF.If the display jumps around in these ranges something doesn't seem right.

author: joeqsmith
author_rank: Super Contributor
timestamp: December 16, 2017, 06:31:21 pm
content: I'm not so sure without seeing what they are doing. For example, I place two meters on my ESD mat and install one lead in the ohms jack. I set both meters to ohms. I then hold the two probes and rub one foot across the carpet without wearing a strap. I am not touching the metal tip, just the handle. It's winter here and the house is starting to get dry. The Fluke 189 measured a minimum of 14M, the Brymen BM869s, 10M. Not a real great experiment but just saying that I am not too concerned without knowing more about what they are doing.

author: EEreloaded
author_rank: Newbie
timestamp: December 16, 2017, 06:55:20 pm
content: I try to describe the situation: I have the meter on my bench, both leads installed, set to resistance mode and min/max activated with view on the min for the pseudo-auto hold function.Before I was about to start the measurements I had both probes in my left hand (no contact to the tips at all, neither my hands nor the tips touching each other) and then “combed” the leads with my right hand from left to right to untangle them. Right in this moment the meter beeps and min read jumps down to 5 Megs. That’s basically it. It’s kind of like a habit, so I don’t think about this “move”. Maybe my old meters just weren’t that sensitive...Sounds pretty much like the effect Joe described. It actually is dry in my hobby room and I didn’t wear my strap.

author: Terry01
author_rank: Frequent Contributor
timestamp: December 16, 2017, 07:10:58 pm
content: I am very new to electronics and all the meters and other pieces of equipment that go with it.I have the Brymen 867s and it does the same as yours (869s), jumps around a bit. I also have the fluke 177 which jumps around a little too with just the probes connected and open circuit but not as much as the Brymen.The Brymen is much more sensitive (and accurate) than the Fluke but when I measure something with both they are very close if not identical although the Brymen jumps around more just sitting on my bench not connected to anything than the Fluke.I have a couple voltage reference modules I use and again the Fluke and Brymen are almost identical when I measure these with both meters. The Fluke settles much quicker than the Brymen so at first I thought the Fluke was a quicker (better) meter, not so!The Brymen just has more resolution and so shows every little blip where the Fluke does not so much. Do as I did and read up on this and things will be much clearer for you. There's a couple guys on YouTube do some excellent videos that are very informative and great viewing too! You'll love it!This is normalYou can relax!The 869s is a great meter (as long as it's not broken) with loads of features to learn about!