NOTE: That should have been 5.6M, but I tried that and it's fine. Definitely only 560k. The new BM786 switches ranges very cleanly at about 650k, no signs of this ranging hysteresis noise effect at all.

That's one of the perils of autoranging meters. If you're on the transition between two ranges it can start toggling between them. Fortunately it's rare that you're measuring something bang on the edge like that.

Does it start oscillating at 555 k?

It happens near the boundary between two ranges, the device can't decide which range to use.

It's because you had the red cable in the COM plug, of course :)

You sure it’s the shirt and not the belly?

Have reproduced on a BM869 with a 565k6 (as measured) resistor. Interestingly, the mains cable I used was an extension cable with no device/load attached, so it appears to be electrostatic coupling (although that does comport with the shirt rubbing stuff). I'm not too worried though, I'm sure the whole dual slope (whatever it's called) DAC technique often has certain values/frequencies that it doesn't like. I'm guessing the dual slope cycling hits a frequency near some multiple/divisor of 50 Hz at 560k. Would be fascinating to see if folks in the US see a slightly different range at 60 Hz mains.

Replicated on three out of three meters at work. Made our company metrologist freak out. :D

DAMMIT, I just bought the EEVBlog BM235, now you are coming out with the BM786. My old Fluke 87 died and I needed a new meter. So I just received my EEVBlog BM235, I wish I could have waited for the 786.

On my Brymen BM867s I was able to replicate the same fault at 560k, 556k, and 529k, but not at 508.5k, where it's back to showing 5 digits. Probably an issue with the bottom of that low MOhm range, specifically.

Surely somebody would have already informed Brymen of this issue during the last 10 years of service

Dude I've run across so many bits of hardware and software than end up having the most obscure quirks imaginable. This is just giving me PTSD :^)

Dave by day, Electrostatic man by night

As the kohm and Mohm segments are flashing, i guess it messes up the autorange part of the software. I've seen 510K and 0.53M on the display. I expect some problems between ohms and kohms too. I'm guessing they need some (more) hysteresis in the range determination before switching and clearing the display.

I wonder if one found their sweet spot in between the range change thresholds if other meters might exhibit the same behavior under similar conditions. Each meter might very well have different ranging thresholds/hysteresis algorithms.

Interesting, my Brymen BM839 has an issue at the lowest voltage range where it is randomly resetting once it switches to it.

Hello, great video, do you by any chance have the complete manual of the multimeter in question?

Sounds like RLC resonance problem. More specifically, oscillation. If so, it will happen in some other values other than 560k!

I did some testing on my BM869s and it seems that there are still some capacitive and inductive input problems. I used a resistance decades and I varied values between 510K-600K, it seems that these areas are the most affected. I used different cables, some shielded and others I shielded myself, in vain, the defect (anomaly) did not disappear. But to shorten the discussion I will tell you what I managed to get after a few hours of testing. I put a capacitor with a value of 47nF - 100nF at the input of BM869s and the device became very stable regardless of the position of the cables or the touch with my hand of its active parts or of the resistive decade. (First, I made measurements in Manual Mode and here it seems to be fine).

Enhorabuena me lo paso genial 😉 contigo y con Joe Smith. Enhorabuena 👏

I just ran into issue today with two BM867s and BM869s when testing some 18650 cells. There was not any AC power within 30 feet from where I was testing. They will not read 67M ohms. Screen just flashes. I ended up having to revert back to using my Fluke 289’s for testing. I cant get any of my Brymen’s to read over 51M ohms. Shouldn’t they be able to read above that with decade box?

I assume that these meters use some variation of the good old dual-slope-integration measurement technique. If that is the case, I could imagine that they may be a lot more sensitive at certain frequencies. Doesn't excuse poor shielding design, grounding etc of course!

I just tried it on my AVO 8 no worries

BM786 is absolutely outstanding multimeter. We have attached a clamp meter to BM786 on mV range and set this clamp to 1mV/A. Then we were troubleshooting some small device with very low standby power consumption. The current this meter was able to register using the third party clamp was down to.10mA! This is absolutely great result. Then when the full power was applied the meter registered 0.36mV and it was accurate reading of 360mA. Many other meters would simply not register such low current of idling device and this one was right on the point! Also we found that during repeatative tasks the AutoHold(tm) selection makes a lot easier to trace some sources of voltage without even looking at the display. This model has great potential. Leads would be nice to get with slightly bigger and bolder handles to be honest. In battery compartment we noticed that batteries potentially if they would leak may damage (questionmark) the internals, hence we placed the fire retardant insulation material cut to the size of 3 batteries between the compartment and the main PCB board. Just a great meter. Confidence of using this meter to obtain accurate results increased in 30 min after we have start using this. It is just great. Temperature was accurate and very quickly measured. Capasitonce was somewhat slow at first on 60uF but then we saw improvement in readings it was good. Give us a second one just to put in the drawer as an investment! This is how it feels great about this meter. Switch we believe while looks a bit like a weak part seems does great the rotation etc though we did not go ballistic in this. It is some serious a value for what it cost. Leads we would not mind to get a better set because Cat 4 rating small attachement( red) not seats properly 100$ yet it so minor issue that no point to worry. Dave, please do more tests and make this "true electrical machine" even better with next releases. Would buy again this meter.Tnx

Tugging on your leads causes your meter to reboot? .. well, I'd get that checked out :-)

Brymen should give a 50% discount.

It’s just the auto ranging threshold, every meter will do it at the range changeover point, needs better hysteresis.

my brand new BM 785 - and same issue :-( but only with standard lenght test leads. Above 100k . If You have use very short test leads, its OK.

The error is just at the level where it switches from kOhm to MOhm. A bigger hysteresis would help.

this multimeter is obtained with the green lee brand the DM860A, but the DM830A is the same as the fluke 87 v with a little more functions these green lee multimeter are excellent nothing to compare to fluke

Doesn't really seem like an issue to me, it's just range hunting. Any autoranging meter that is trying to measure something bouncing between borders is going to do that, ISTM.

Would like to see the insides of the substitution box! ;)

I have got a 869S and it happens with 470k, 560k, 680k and 1M. Very strange!

Clearly the wires for the test leads require some shielding from induction.

Maybe it only happens on thursdays too

Anyone tried this on a 60Hz mains system?

Hmm a new eevBlog multimeter. As far as I can see, this is not the one teased in EEVblog #1328. What happened to that one?

Knowing nothing about multimeter design specifically (gotta state the qualifications! 🤣), it seems to me like a firmware bug. The meter never technically fails, but stops providing a reading as it changes ranges in that specific resistance range. Could be as "simple" a fix as extending the autoranging hysteresis in firmware. No idea how updatable a typical multimeter is without hardware changes though -- I'm guessing the answer is "not very."

Put a 0.1uF cap across the meter.

That is really wierd.

What next, test it in a Copper Faraday Cage? =P

So the lesson learned here is when doing an important measurement, don't rub the cables across your belly like a crazy bloke or hold them closely agaist mains leads...🙄

They should change the name to the BS869

My 869s do the same...

better this than some wrong value

I shouldn't have watched this video....

Conclusion: it is not a Fluke, so once in a while you will notice strange behaviour like this...

Response to ac noise? Very likely, most manufacturer don't shield their test probe cable for noise, Is it possible that is the sampling frequency of this meter? Let me guess, it is made in........you know where. Made to fail in critical moments.

First yeaaaaa

An unfortunate error in a precision multimeter that causes a loss of prestige.

hmm your belly must be noisy.

You just discovered static electricity!!! I will also tell you that if you fill the interior with water very curious things happen or if you drop it from 70,000 meters while measuring, but I thought it was an electronics channel and what does this have to do with it? Are you out of ideas to create content? It goes back to the basics that everything we think we know is very questionable and would make us rethink the results in other orders of magnitudes, which is where we are going, it is an idea.