Author Topic: Brymen BM789  (Read 23531 times)

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Offline groovesonshuntTopic starter

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Brymen BM789
« on: January 16, 2023, 06:20:51 pm »
I just got my new Brymen BM789 today, and I am very pleased with the build quality.

The first thing that I did noticed was, that the meter moves a lot when it's on the stand while I use the dial.
Can anyone tell me if your 789 has a rubber ring around the edge of the stand?
Mine came with the 789011 firmware, and when I look at the picture on the .eu website, there seem to be a rubber ring around the edge of the stand.

What about your 789.....does it have a non-slip coating?
 

Online J-R

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Re: Brymen BM789
« Reply #1 on: January 16, 2023, 10:21:05 pm »
Nothing on mine.  I don't see anything in any photos either.

You could probably find a small bit of rubber hose, split it open and attach it to the stand.
 
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Offline Fungus

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Re: Brymen BM789
« Reply #2 on: January 17, 2023, 03:06:12 am »
The first thing that I did noticed was, that the meter moves a lot when it's on the stand while I use the dial.

All meters do that.  :-//
 

Offline Neutrion

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Re: Brymen BM789
« Reply #3 on: January 26, 2023, 02:33:16 pm »
Also nothing on mine.
 

Offline BillyO

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Re: Brymen BM789
« Reply #4 on: January 26, 2023, 03:39:35 pm »
Nothing on my 786 (same form factor) either.

I use a non-slip anti-static mat on my bench.  As such it (nor any other meter) does not move when I use it on the stand.

Don't see anythjing in the picture either.  This shot is from Brymen's EU site.

« Last Edit: January 26, 2023, 03:44:11 pm by BillyO »
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Offline Fungus

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Re: Brymen BM789
« Reply #5 on: January 26, 2023, 03:46:55 pm »
The first thing that I did noticed was, that the meter moves a lot when it's on the stand while I use the dial.

I think all multimeters do that.  :popcorn:

AFAICT the stand is there for the viewing angle, not for using it one-handed.
« Last Edit: January 26, 2023, 04:06:29 pm by Fungus »
 

Offline Pfriemler

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Re: Brymen BM789
« Reply #6 on: April 25, 2023, 04:44:04 pm »
I just got my new Brymen BM789 today, and I am very pleased with the build quality. ...

I am not. I got one from Welectron with a crooked amps socket and frayed red insulators. Nevertheless, the leads plug in well and everything is functional.
But no chinese crap I ever got was like that.
Besides this, my BM789 is - related to my AD584 reference, checked with a well calibrated HP 34401A - on the lower side of the 0,03% tolerance. Even 30$ stuff from Amazon is more accurate, not to mention my older (but self calibrated) cheapos.
Nevertheless, it's fine and fast. I love the fast resistor autoranging and the low-Z mode.
once you do it right, it works :-)
 

Online J-R

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Re: Brymen BM789
« Reply #7 on: April 25, 2023, 07:20:40 pm »
Can you post some photos of the areas in which this is not very accurate?
 

Offline Pfriemler

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Re: Brymen BM789
« Reply #8 on: April 26, 2023, 02:14:43 pm »
I gave it a closer look. It's more on the upper side. And it's well within the specs as expected, no doubt. But it could be better...

Given a AD584 with its test protocol  (measured with an Agilent 34401A), and a measurement with an well calibrated HP 34401A (which values are slightly above), I referred to the average of both to calibrate my meters (if possible)
The average values of the 2.5/5/7.4/10V thus are 2,49961, 5,001085, 7,50091 and 10,00183 volts
My Brymen BM789 reads
2,4999 (+0,01%), 5,002 (+0,02%) in the 6V range and
2,500 (+0,02%), 5,003 (+0,04%), 7,503 (+0,03%) and 10,005 (+0,03%). If I had 5.001, 7.501 and 10.002, it would be perfect.  :)
I'll watch this... maybe the values will get more accurate with a longer on time and near to 20 °C (it's ~24 °C in my hobby room)

And: Most of my cheapos simply do not have that resolution. So a 2.50, 5.00, 7.50 and 10.00 looks better on the first view, but does not have to.

If I compare the AD584 test protocol to the HP 34401, all deviatons are 0,02% or less.
Brymen to AD584 is again within specs (+0,02% @2.5V, +0,03% @5V (+0,04%) in the 6V range. +0,04% at 10V in 60V range.
Absolutely nothing to blame.

I try not to look at the amps socket and everything will be fine ... :clap:

once you do it right, it works :-)
 

Online J-R

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Re: Brymen BM789
« Reply #9 on: April 27, 2023, 06:43:23 am »
I have concerns with taking the average of two 34401A units.  Do you have the calibration data for each?  One is probably better than the other depending on the input provided.  So an average may make things worse.
What about calibration data for the AD584?

Regardless, 3 counts away on this 66,000 count DMM is not an issue that needs to be corrected in my opinion.  It is not valid to compare how many counts it is out vs. another DMM that is only 6,000 counts, for example.

Also, I am not sure if it is possible to get this any better since the calibration points appear to be at 0 and +/- 3V for the 6V range.

I tested my BM789 and it was 3.0001V and 6.0002V at 21C.  I experimented with the DC calibration but am not sure if it completed.  After the +/- 1,000V calibration point, it entered the AC+DC calibration and I did not have the information on what to input so had to exit the calibration.  Afterwards it still read the same as before.
 

Offline Pfriemler

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Re: Brymen BM789
« Reply #10 on: April 27, 2023, 10:47:29 am »
I respect your concerns. To make it more clear:
a) My experience is that even cheapos are shipped almost perfect calibrated (within their limits, but far better than the specs). That's what I expected with the Brymen. Of course it's possible that both devices are wrong and the Brymen is right ...

b) The Agilent meausurements _are_ the calibration data delivered with the AD584.
The HP data I do not know, but I was told it is calibrated regulary.
Taking the pure AD584 calibration data, my BM789 is even a bit worse (but also within the specs) - the HP taken into average makes it better :-)

once you do it right, it works :-)
 

Offline NoisyBoy

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Re: Brymen BM789
« Reply #11 on: April 27, 2023, 07:13:55 pm »
I echo J-R's comments.  BM789 is pushing the accuracy limit for handheld in this price range, so I consider it to be really good as long as it is within spec for a factory calibration.  60,000 count does not help, had it been a 6000 count meter, you would probably think it is perfect.

You can always send it to Welectron for a separate calibration, but I doubt it will get any better.  Most cal labs adjust the meter to be within spec, but not necessarily optimized for the smallest error across the entire range. 
 

Online Hydrawerk

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Re: Brymen BM789
« Reply #12 on: April 29, 2023, 06:21:09 pm »
It seems that Brymen BM789 is rebranded as Metrel MD 9055. https://www.metrel.si/en/shop/DMM/digital-multimeters/md-9055.html
The picture on website and in the datasheet was probably manipulated... The actual product has 60 000 counts not dual lcd.
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Online Hydrawerk

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Re: Brymen BM789
« Reply #13 on: April 29, 2023, 06:23:08 pm »
Actual photos of Metrel MD9055 show the real LCD! It is not a dual readout lcd.
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Online Hydrawerk

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Re: Brymen BM789
« Reply #14 on: August 05, 2023, 11:44:18 pm »
I am wondering about buying a Brymen BM789. But is there a competitive DMM in this price category? Some Appa, UNI-T, CEM, Extech? I need some 40 000-60 000 readouts, LoZ, proper input protection and beepjack.
Keysight and Fluke are too expensive for me.
Edit:
I have a BM829s since 2016 and it is quite OK. I just want one more DMM.
« Last Edit: August 06, 2023, 12:05:50 am by Hydrawerk »
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Offline Fungus

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Re: Brymen BM789
« Reply #15 on: August 05, 2023, 11:49:12 pm »
I am wondering about buying a Brymen BM789. But is there a competitive DMM in this price category?

No.

(well, there's some other Brymens...and the blue EEVBLOG meter which is a Brymen)
Keysight and Fluke are too expensive for me.
[/quote]

You're not missing much. Brymens are just as good for measuring and reliability. Flukes are only worth it if other people are going to judge you by the meter you carry.

 

Online Hydrawerk

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Re: Brymen BM789
« Reply #16 on: August 06, 2023, 12:08:18 am »
Flukes are only worth it if other people are going to judge you by the meter you carry.
Or if you want to have it calibrated without problems all over the world. Or you really want to use it in a large factory or so.
(There might be some problems with Brymen calibration... )
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Online EEVblog

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Re: Brymen BM789
« Reply #17 on: August 06, 2023, 02:13:55 am »
You're not missing much. Brymens are just as good for measuring and reliability. Flukes are only worth it if other people are going to judge you by the meter you carry.

 

Offline sonpul

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Re: Brymen BM789
« Reply #18 on: August 06, 2023, 07:59:21 am »
I am wondering about buying a Brymen BM789. But is there a competitive DMM in this price category?
No. I have not seen another such DMM. Even BM869s I will say No.
 

Online J-R

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Re: Brymen BM789
« Reply #19 on: August 06, 2023, 10:06:03 am »
I am wondering about buying a Brymen BM789. But is there a competitive DMM in this price category? Some Appa, UNI-T, CEM, Extech? I need some 40 000-60 000 readouts, LoZ, proper input protection and beepjack.
Keysight and Fluke are too expensive for me.
Edit:
I have a BM829s since 2016 and it is quite OK. I just want one more DMM.
The Flir DM93 has been on sale for $149.99 for a while, seems out of stock currently, not sure if it will be back, maybe keep an eye out.  You could check ebay for both the DM93 and the slightly lesser DM92.

Another option is the 121GW.
 

Offline Fungus

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Re: Brymen BM789
« Reply #20 on: August 06, 2023, 11:26:24 am »
Flukes are only worth it if other people are going to judge you by the meter you carry.
Or you really want to use it in a large factory or so.

Isn't that what I said?

(There might be some problems with Brymen calibration... )

Are you talking about calibration or adjustment? A decent lab can calibrate any meter and produce a certificate.

If adjustment is needed on a meter of this class then you should probably regard it as "damaged" and get a new one.
 

Offline Fungus

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Re: Brymen BM789
« Reply #21 on: August 06, 2023, 11:48:54 am »
I am wondering about buying a Brymen BM789. But is there a competitive DMM in this price category?
No. I have not seen another such DMM. Even BM869s I will say No.

BM869s has a higher CAT rating and a longer history.

The BM789 is much newer and has had a few firmware tweaks since introduction (eg. in autoranging). I think the tweaking stage is over now though.

https://www.eevblog.com/forum/testgear/brymen-bm789/msg4349518/#msg4349518

To their credit: Brymen was extremely responsive to early testing here on EEVBLOG.
 

Online EEVblog

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Re: Brymen BM789
« Reply #22 on: August 07, 2023, 12:57:14 am »
BM869s has a higher CAT rating

That's of little consequence to most people, especially when you consider the 869 is more designed as a precision high count lab meter than a field test meter. And the 780 series already has 600V CAT-IV which is as a good as it gets from other manufacturers like Fluke for example.
And you pay for that with increased size and weight as well.
 

Offline Fungus

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Re: Brymen BM789
« Reply #23 on: August 07, 2023, 01:35:35 am »


If you want a more robust meter than the BM789, Brymen does an "industrial" range.

(I know you know this...but not everybody does).

As for the smaller fuse in the Brymen: I'd trade that fuse for input jack alert any day of the week.
 

Offline floobydust

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Re: Brymen BM789
« Reply #24 on: August 07, 2023, 02:09:39 am »
To be clear - there is no North American support for these Brymen multimeters such as repair, calibration, firmware updates? It's gotta be shipped trans-ocean for any of that?
 


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