New Brymen BM2257 Multimeter

[EEVblog]

Just found out about this through a Youtube comment.
Basically a BM235 with AutoHold, Bargraph, and serial coms.
US$127

http://www.brymen.com/PD02BM2250_2257.html
http://www.brymen.com/images/ProductsList/BM2250_List/BM2250-manual-Print1-r3.pdf

[Fungus]

96 Euros + Tax

https://brymen.eu/shop/bm2257/

[rsjsouza]

That is one of the most featured (and well rounded) compact meter I have seen. It corrects three weaknesses of its cousin BM257: the autohold, the higher capacitance measurement of 10mF and a decent diode voltage measurement of 3V. The logic level takes a hit, at 200k @ 3V (the other is 500kHz @ 3V and 1MHz @ 5V).

[Fungus]

The four-function Ohms/Diode/Continuity/Capacitance range position is a bit of a turn off. 

Would it have killed them to add an extra click on the dial?

[Furna]

It looks very promising but if it doesn't have a blue holster I won't buy it. 
Seriously, I was thinking about a low cost and compact meter while also "sponsor" somehow EEVblog so I was evaluating the blue BM235.

[EEVblog]

It looks very promising but if it doesn't have a blue holster I won't buy it. 
Seriously, I was thinking about a low cost and compact meter while also "sponsor" somehow EEVblog so I was evaluating the blue BM235.

I've emailed Brymen...

[ArdWar]

The four-function Ohms/Diode/Continuity/Capacitance range position is a bit of a turn off. 

Would it have killed them to add an extra click on the dial?

For double opposite contact you can't have more than 180° turn, and they probably don't want to change the already running 8-notch mold that they also use for many other models.

[J-R]

I wouldn't compare the BM225x models to the BM23x series, would be the BM25x series instead.  So BM251 -> BM2251 and BM257 -> BM2257.
On the BM25x they placed the EF function on the Hold button, which in hindsight was a strange choice.  New models now have EF on the AC V selector position instead along with VFD, allowing for the logical return of AutoHold.
"Multitalented and Compact; Loaded with Nice Up-to-date Features!"
The mV logic level Hz function is found on many of their other models.  So nothing much new about that either.


There are also the new BM280xCSE models:
"This 2800 CSE meter series is a safety Category and EMI Shielding Enhanced (CSE)
version of our popular 800 practical meter series. Apart from the added up-to-date
features and improvements in safety ratings, it is also equipped with EMI shielding on
both sides of the circuitry module to improve measurement stability under harsh
electromagnetic interferences, especially in the electrical and automotive industries."

[Furna]

... and due to the fact that last March I bought a BM869s you can expect soon a BM8869s ...
I am joiking but I'd not be too much surprised 

[EEVblog]

It looks very promising but if it doesn't have a blue holster I won't buy it. 
Seriously, I was thinking about a low cost and compact meter while also "sponsor" somehow EEVblog so I was evaluating the blue BM235.

I've emailed Brymen...

I have the FOB price, it's not much more than the BM235...
Hmm, what to do.
Do I offer yet another meter, (with the new pocket one coming, that would be 5 meters), or do I phase out the BM235 and replace it with this at a slightly higher price?

[electr_peter]

I looked at BM2257 specs carefully - it is very similar and slightly better than BM235 in some aspects, but not in other aspects. Very similar meter overall, not sure if it worth extra price over BM235.
Definitely do not offer both at once, as these models are very similar. Whether to replace or not, not sure, probably not for the same reasons.

[J-R]

... and due to the fact that last March I bought a BM869s you can expect soon a BM8869s ...
I am joiking but I'd not be too much surprised 

A BM2869s...  There are some things they could improve slightly...

I have the FOB price, it's not much more than the BM235...
Hmm, what to do.
Do I offer yet another meter, (with the new pocket one coming, that would be 5 meters), or do I phase out the BM235 and replace it with this at a slightly higher price?

So are they willing to let you brand the BM2257 as-is?  Or would you drop a feature or two and get something like a BM2255?
Seems like you'd have to insist on the blue-adjacent paper white backlight, though.  Amber would clash with blue.

[EEVblog]

I looked at BM2257 specs carefully - it is very similar and slightly better than BM235 in some aspects, but not in other aspects. Very similar meter overall, not sure if it worth extra price over BM235.

Accuracy specs aren't really that important in this lecel of meter, they are all basically the same.
In this case the BM2257 has AutoHold and bargraph like the BM786, plus serial.
I could still offer the BM235 at a permanent discount and make less margin on it for those who are watching every dollar.

[J-R]

I looked at BM2257 specs carefully - it is very similar and slightly better than BM235 in some aspects, but not in other aspects. Very similar meter overall, not sure if it worth extra price over BM235.
Definitely do not offer both at once, as these models are very similar. Whether to replace or not, not sure, probably not for the same reasons.

Comparing the features and specs of the BM235, BM257s and BM2257 it seems a lot of the BM2257 specs follow the BM235 while the physical layout is identical to the BM257s (but different from the BM235).  Also, I see that the BM257s has the full blown AutoCheck feature where it automatically switches between "LoZ DCV, LoZ ACV & OHMS" while the BM235 and BM2257 are just AutoV.

Also the BM2257 has the IR interface (as does the BM25x series).

My opinion on these lower-end DMMs is that features are slightly more important than specs.  The last digit is going to be +/- 2d or +/- 4d on top of the percent-of-reading spec.

[Furna]

A BM2869s...  There are some things they could improve slightly...

Sure BM2869s ... I am not good at understanding how companies name their products series over the years.
The only thing that comes to my mind missing on BM869s is the duty cycle for AC ... I really do not miss it; my BM869s sits on the bench and rarely touches AC.
Sure WiFi ... but I am not a fun of WiFi. I am still over USB for DMMs.

Accuracy specs aren't really that important in this lecel of meter, they are all basically the same.
In this case the BM2257 has AutoHold and bargraph like the BM786, plus serial.
I could still offer the BM235 at a permanent discount and make less margin on it for those who are watching every dollar.

I agree, accuracy IMHO is not a pillar for a small/cheap DMM ... I want something that I can bring easily with me and has as much features as possible.
The feature of BM2257 I most appreciate is the bar-graph; Auto-hold convenient ... serial just a plus.

I like the fact that EEVblog shop has only a few DMMs; I feel like an Electronic Engineer already made a selection on my behalf so I do not have to go through hundreds f pages trying to avoid stuff for electricians, automotive etc.
For this reason I would like to see BM235 removed from the shop ... but I see Dave's point.
So all in all he is right IMO; BM235 discounted and BM2257 offered as his successor.

[EEVblog]

Sure BM2869s ... I am not good at understanding how companies name their products series over the years.

My new pocket meter is the 1980s 

I agree, accuracy IMHO is not a pillar for a small/cheap DMM ... I want something that I can bring easily with me and has as much features as possible.
The feature of BM2257 I most appreciate is the bar-graph; Auto-hold convenient ... serial just a plus.

I like the fact that EEVblog shop has only a few DMMs; I feel like an Electronic Engineer already made a selection on my behalf so I do not have to go through hundreds f pages trying to avoid stuff for electricians, automotive etc.
For this reason I would like to see BM235 removed from the shop ... but I see Dave's point.
So all in all he is right IMO; BM235 discounted and BM2257 offered as his successor.

I don't think the BM2257 will work unless I permanately discount the BM235
Brymen are sending me a sample mid Sept. And they said they can do the same blue holster and rebranding without changing the model number.
FYI, Brymen won't let me just pick any model number as it requires going through the UL certification again.

[EEVblog]

Accuracy specs aren't really that important in this lecel of meter, they are all basically the same.

So much so that I didn't even mention accuracy in my Beginner meter video I just released.

[2N3055]

A BM2869s...  There are some things they could improve slightly...

Sure BM2869s ... I am not good at understanding how companies name their products series over the years.
The only thing that comes to my mind missing on BM869s is the duty cycle for AC ... I really do not miss it; my BM869s sits on the bench and rarely touches AC.
Sure WiFi ... but I am not a fun of WiFi. I am still over USB for DMMs.

Accuracy specs aren't really that important in this lecel of meter, they are all basically the same.
In this case the BM2257 has AutoHold and bargraph like the BM786, plus serial.
I could still offer the BM235 at a permanent discount and make less margin on it for those who are watching every dollar.

I agree, accuracy IMHO is not a pillar for a small/cheap DMM ... I want something that I can bring easily with me and has as much features as possible.
The feature of BM2257 I most appreciate is the bar-graph; Auto-hold convenient ... serial just a plus.

I like the fact that EEVblog shop has only a few DMMs; I feel like an Electronic Engineer already made a selection on my behalf so I do not have to go through hundreds f pages trying to avoid stuff for electricians, automotive etc.
For this reason I would like to see BM235 removed from the shop ... but I see Dave's point.
So all in all he is right IMO; BM235 discounted and BM2257 offered as his successor.

I can tell you what could be done for new gen 869:

- Remembering preferences. I prefer meter to be quiet unless in continuity mode. You can do that, but EVERY single time you power it on. Just remember setup preferences.
- AC coupling in AC mV mode.  That is not a big deal, but a chance to make it better when redesigning.
- Auto Hold. That is not important to me, but lot's of people
- Diode beep ( a lá Fluke) is also something a lot's of people asked for.

For me literally remembering preferences is only annoying thing about the meter. That shows you how good it is.

[0Anonym]

I have looked into getting a Quality meter over the past few Weeks and my choices where the BM235, the 257s and the 2257. I didn’t quite understand why I couldn’t find anything about the BM2257, but I didn’t know at the time that it was so new.
That means I will have to wait a bit longer until the new EEVBlog edition comes out.

[Furna]

I can tell you what could be done for new gen 869:

- Remembering preferences. I prefer meter to be quiet unless in continuity mode. You can do that, but EVERY single time you power it on. Just remember setup preferences.

I see your point ... indeed it already remembers every function you set.

- AC coupling in AC mV mode.  That is not a big deal, but a chance to make it better when redesigning.
- Auto Hold. That is not important to me, but lot's of people
- Diode beep ( a lá Fluke) is also something a lot's of people asked for.

Never had a Fluke so I not missing that feature 

For me literally remembering preferences is only annoying thing about the meter. That shows you how good it is.

Agree

[Furna]

My new pocket meter is the 1980s 

I am not so lucky; EE passion went Lo&Hi, moved apartment/house multiple times across different continents.
The oldest meter I have is the MAS-345; I date it back to 2005-2006 but not sure.

I don't think the BM2257 will work unless I permanately discount the BM235
Brymen are sending me a sample mid Sept. And they said they can do the same blue holster and rebranding without changing the model number.
FYI, Brymen won't let me just pick any model number as it requires going through the UL certification again.

OK I took a note: part 2 of the Beginner meter video is scheduled for the end of last week of Sept and will feature a blue BM2257 

BTW I see no reason why you might want to change the model number

[cv007]

Note the backlight time listed in the manual- 16 minutes. I was happy when I discovered my 857s had 256 seconds, which is better than others but sometimes still not long enough (I do like my 857s).

[RFDx]

What's the display backlight colour? On the EU website it shows a paper white backlight but in the datasheet it's amber.

[HKJ]

Where it has a big advantage over BM235 is the computer connection. I often find it useful to link a meter to a computer and record data.

[RAPo]

Currently, the BM2257 is out of stock.
I received a mail from Brymen (Adrian Wieczorkowski) stating that it will be in stock again around 27 September.
Then you can order it from www.brymen.eu.

[0Anonym]

Sorry if this is a stupid question, but would you guys choose the Gossen Metrawatt METRALINE DM62 over the BM 2257?

[EEVblog]

I didn’t quite understand why I couldn’t find anything about the BM2257, but I didn’t know at the time that it was so new.

Given that Brymen can't send me one for a few weeks means that it's not ready yet. Does anyone actually have stock? Wouldn't surprise me if there are delays. The original BM235 was something like 9 months late from when they promised. And the BM786 was delayed too.

[EEVblog]

Sorry if this is a stupid question, but would you guys choose the Gossen Metrawatt METRALINE DM62 over the BM 2257?

Seems like a much bigger meter.
The thing I like most about the BM235/257/2257 is that it's small, and it has big digits.

[Fungus]

Sorry if this is a stupid question, but would you guys choose the Gossen Metrawatt METRALINE DM62 over the BM 2257?

No. It's much more expensive and it's a horrible color.

[0Anonym]

Thanks for the responses.

Can someone explain why some Multimeters have joined AC and DC switch Positions (for example the BM235) and some have split AC and DC switch Positions (like the BM2257)?

To me it seems like, even though its only a very small detail, it seems like a simplification when working in a rush.

[HKJ]

Can someone explain why some Multimeters have joined AC and DC switch Positions (for example the BM235) and some have split AC and DC switch Positions (like the BM2257)?

To me it seems like, even though its only a very small detail, it seems like a simplification when working in a rush.

It a design decision, there is a certain number of modes that a meter has and they must be distributed over a number of switch positions. Some can be combined, others need a separate position. Then it is up to the designer how to distribute them, some prefer shared AC/DC (May not be possible on a good meter), some prefer to combine ohms/diode/cont. in a single position.

[xKertx]

What's the display backlight colour? On the EU website it shows a paper white backlight but in the datasheet it's amber.

On the brymen.com site it says "Warm Amber Backlight".

[RFDx]

What's the display backlight colour? On the EU website it shows a paper white backlight but in the datasheet it's amber.

On the brymen.com site it says "Warm Amber Backlight".

Thanks. On brymen.eu it's displayed with a (paper)white backlight unless that's just a picture with the backlight turned off. The datasheet however shows the BM2257 with the "warm" amber backlight.

[Furna]

I didn’t quite understand why I couldn’t find anything about the BM2257, but I didn’t know at the time that it was so new.

Given that Brymen can't send me one for a few weeks means that it's not ready yet. Does anyone actually have stock? Wouldn't surprise me if there are delays. The original BM235 was something like 9 months late from when they promised. And the BM786 was delayed too.

The polish distributor brymen.eu listed it as available for a few days ... currently it is not possible to order it.
Official distributors Welectron and Eleshop do not list at all.

I guess we can expect some delays and probably your sample could be one of the first.

[EEVblog]

I guess we can expect some delays and probably your sample could be one of the first.

I assume I'm getting the first production batch run.
I wonder if it will have a firmware programming port like the BM786 has?

[0Anonym]

Does it make any sense to contact the Polish reseller even though someone else from the forum contacted them before or is Brymen known for not sharing Information in advance?

[Furna]

Does it make any sense to contact the Polish reseller even though someone else from the forum contacted them before or is Brymen known for not sharing Information in advance?

What inforamtion are you looking for?
Why buy from a Polish reseller/distributor if you are German and there are reseelrs/distributots in your own country?
I guess every reseller/distributor will anser you ...

[EEVblog]

Got it!
Orange backlight is very nice, as is the very fine bargraph.
I note that CATII marking is missing as per the new standard.

[J-R]

What does it look like without the backlight on?  Just a white LCD?
Are they able to offer it with the paper-white backlight or just the amber?

[EEVblog]

What does it look like without the backlight on?  Just a white LCD?
Are they able to offer it with the paper-white backlight or just the amber?

Same transflective sceen as the BM235. BM235 is slightly better at higher angles.
Haven't asked about backlight.

[nidlaX]

EEVblog BM2257 waiting room

[Ice-Tea]

Am I the only one bothered by the A <-> mA inversion? 

[J-R]

Am I the only one bothered by the A <-> mA inversion? 

Well, the 2257 is basically a newer 257, so in that regard the jacks haven't moved.
Also, the BM78x series has this arrangement, so it's probably their current standard.

[EEVblog]

Am I the only one bothered by the A <-> mA inversion? 

Teardown might be interesting...

[Ice-Tea]

Am I the only one bothered by the A <-> mA inversion? 

Well, the 2257 is basically a newer 257, so in that regard the jacks haven't moved.
Also, the BM78x series has this arrangement, so it's probably their current standard.

Still bothered 

[tautech]

Am I the only one bothered by the A <-> mA inversion? 

Yeah it's 100% dumb on the same class of DMM.

The world is already confusing enuf......

[J-R]

Am I the only one bothered by the A <-> mA inversion? 

Yeah it's 100% dumb on the same class of DMM.

The world is already confusing enuf......

Talk about confusing; for the third time, the 2257 is based on the 257, not the 235, so there are no jack changes as you can see from this review 12 years ago: https://www.eevblog.com/forum/testgear/brymen-bm-257-pictures-and-mini-review/

[robert.rozee]

Talk about confusing; for the third time, the 2257 is based on the 257, not the 235

but is the 257 not based on the 235? or is the 235 based on the 257? or is there some other intermediate model that we have not seen yet that links them all together?   


cheers,
rob   :-)

[shapirus]

... and due to the fact that last March I bought a BM869s you can expect soon a BM8869s ...
I am joiking but I'd not be too much surprised 

A BM2869s...  There are some things they could improve slightly...

Yeah definitely. I want a BM869s with auto hold, LowZ voltmeter, maybe faster autoranging and 60k counts, beep in diode mode if the diode is shorted, and... and... I guess that's all: unfortunately, the BM869s is good enough as it is, there's not much to improve upon.

[Furna]

Teardown might be interesting...

Definitely! 

[EEVblog]

but is the 257 not based on the 235? or is the 235 based on the 257? or is there some other intermediate model that we have not seen yet that links them all together?   

The BM235 came after the BM257.
I wanted to sell the orignal BM257 but they said no, and to wait for the BM235 they were working on, which took about a year BTW.

[J-R]

A thought on the jack placement:

If you line up all of the Brymen DMMs you can see that they really only have to keep track of a handful of building blocks: enclosures, PCBs, jacks, LCDs, etc.  And I'm confident the final assembly is done by hand.  So it's trivial to add another product to their lineup because they just need to spray the top cover a little differently, apply different stickers and have the pick/place machine add or remove components as the PCB goes by.  Then it's all brought together for assembly/calibration/etc.  They don't have to place an order for a million units and hope they sell over the next 5 years; they can make just enough for that quarter's demands.

To bring that paragraph together, I think they are always going to be adding new products on a regular basis to cover even the furthest corners of the market.  There are probably just as many people who insist on having the A jack next to common as there are people who want mAuA next to common.

Looking back through DMM design, it seems a lot of them don't have a mA jack at all, only A - COM - V, in that order.  So when a designer was initially adding mAuA they probably placed to the side to avoid offending existing users.  Eventually, designs came out with the order changed to what is maybe a more common arrangement of A -mAuA - COM - V, of which Fluke and Brymen's high-end DMMs currently follow.

Ultimately, test equipment is SO different, it's never going to be realistic to standardize on this or even things like selector switch order.  You always need to think before you leap...

[EEVblog]

They don't have to place an order for a million units and hope they sell over the next 5 years; they can make just enough for that quarter's demands.

Brymen don't even do that, they never carry excess stock. They literally make to order, and there is at least a two month lead time on all orders. Dealers like myself have to plan ahead and work around this.
Many times I have forgotten this and been left without stock for months.

[EEVblog]

Teardown photos:
https://www.flickr.com/photos/eevblog/albums/72177720320285816

[Fungus]

What's with all the wires?

[EEVblog]

What's with all the wires?

PCB routing constraints I would presume. Probably compliance reasons forcing a certain layout and they have to work around that.

[Furna]

What's with all the wires?

PCB routing constraints I would presume. Probably compliance reasons forcing a certain layout and they have to work around that.

Compliance with?
I have the idea that the more cables you put in a DMM the less compliant with anything.

From the functionality perspective I do not really care; if it measures within specs I am fine.

[EEVblog]

What's with all the wires?

PCB routing constraints I would presume. Probably compliance reasons forcing a certain layout and they have to work around that.

Compliance with?

The various CAT requirements and the Low Voltage Directive (LVD) 2006/95/EC etc

For example, my new 1980s pocket meter from Sanwa has just had to have some PCB changes in terms of creepage distances due to the LVD requirements.

[floobydust]

Teardown photos:
https://www.flickr.com/photos/eevblog/albums/72177720320285816

From the pic, confirm the ferrite bead L4 is actually soldered, it looks bad. Likely for current measurement function.
No offense Dave but Brymen still has poor PCB design. El crapola footprints the wrong size, as always. I think they are better with this board but there is a limit as to how oversized a footprint can be. No idea why a bunch of traces have removed soldermask on them. Hint: not a guard-band lol.

[EEVblog]

From the pic, confirm the ferrite bead L4 is actually soldered, it looks bad. Likely for current measurement function.

Joint looks fine from that photo, the pad likley extends under the component.

[blue_lateral]

Do I offer yet another meter, (with the new pocket one coming, that would be 5 meters), or do I <snip>

Sure BM2869s ... I am not good at understanding how companies name their products series over the years.

My new pocket meter is the 1980s 

<snip> For example, my new 1980s pocket meter from Sanwa has just had to have some PCB changes in terms of creepage distances due to the LVD requirements.

I've googled the crap out of this and got nowhere. I gather there is a new EEVblog pocket meter in the works? The only references I can find are to a Sanwa pocket meter from about 6 years ago that is no longer in the store. I'm just curious. Is there a thread somewhere?

[EEVblog]

I've googled the crap out of this and got nowhere. I gather there is a new EEVblog pocket meter in the works? The only references I can find are to a Sanwa pocket meter from about 6 years ago that is no longer in the store. I'm just curious. Is there a thread somewhere?

No thread. It's my own branded updated version of the PM3

[J-R]

I've googled the crap out of this and got nowhere. I gather there is a new EEVblog pocket meter in the works? The only references I can find are to a Sanwa pocket meter from about 6 years ago that is no longer in the store. I'm just curious. Is there a thread somewhere?

No thread. It's my own branded updated version of the PM3

Have you considered branding these Sanwa kits:
https://overseas.sanwa-meter.co.jp/products/teaching_materials/kit-8d.html
https://overseas.sanwa-meter.co.jp/products/teaching_materials/pc20tk.html

[EEVblog]

I've googled the crap out of this and got nowhere. I gather there is a new EEVblog pocket meter in the works? The only references I can find are to a Sanwa pocket meter from about 6 years ago that is no longer in the store. I'm just curious. Is there a thread somewhere?

No thread. It's my own branded updated version of the PM3

Have you considered branding these Sanwa kits:
https://overseas.sanwa-meter.co.jp/products/teaching_materials/kit-8d.html
https://overseas.sanwa-meter.co.jp/products/teaching_materials/pc20tk.html

Interesting. Didn't know they had kits.
Don't know why they have the DCV adjust pot, that seems kinda dumb from a practicality point of view.
The one problem with Sanwa is that their FOB prices are not cheap.

[Fungus]

Don't know why they have the DCV adjust pot, that seems kinda dumb from a practicality point of view.

I assume they aren't calibrated. 

[Kleinstein]

The PCB for the BM2257 looks a bit simpler (less chips) than the BM257. In the data sheet the AC frequency range is quite limited. I wonder if the meter uses some digital RMS internal to the DMM chip - still not mentioning the fast response typical for digital RMS.

The input jack-PCB looks rather similar to the 257 version where I have found pictures.  An update for additional slots and likely possible to fit the new version also to the 257 (or already used in later versions of the 257).

[Fungus]

TRMS bandwidth isn't something I'd go out of my way for in a DMM these days.

I'm sure a $25 FNIRSI oscilloscope can run rings around any DMM when it comes to measuring AC over a couple of kHz, and 12-bit oscilloscopes are under $400.

It's not the 1980s. 

[floobydust]

I won't use a low bit scope to measure ACmV when I'm looking for small dB losses. Love the 80's and multimeters good for over 1.5kHz when needed. The Sanwa kit and pocket meters are not true-RMS, 400Hz spec. as well.
It's OK I'm not expecting the world in something low cost and compact. I'm more worried about them (Sanwa) passing the BBQ lighter test lol

[EEVblog]

The PCB for the BM2257 looks a bit simpler (less chips) than the BM257. In the data sheet the AC frequency range is quite limited. I wonder if the meter uses some digital RMS internal to the DMM chip - still not mentioning the fast response typical for digital RMS.

Yes, all the low end meters from every brand have on-chip true RMS conversion these days.

[floobydust]

I find the low-end multimeters are usually running 8-bit clunker MCU's with the true-RMS done as a H/W DSP section AC-coupled and good to around 1.5kHz
Not sure what silicon-base Brymen is running in this BM2257 but AC freq. response seems to be 40-1,000Hz.

Sanwa pocket multimeters using e.g. Fortune Semiconductor FS9721-LP3 is just a basic rectifier 40-400Hz rated.

[EEVblog]

I find the low-end multimeters are usually running 8-bit clunker MCU's with the true-RMS done as a H/W DSP section AC-coupled and good to around 1.5kHz
Not sure what silicon-base Brymen is running in this BM2257 but AC freq. response seems to be 40-1,000Hz.

Actually, a 32bit clunker, probably the same as in the 78x series, as they seemed to have switched from ROM based devices to flash now, so makes sense to standardise.

[Kleinstein]

For a modern DMM chip including digital RMS makes absolute sense. SD ADCs can work up to the audio range and the extra math to calculate the RMS result is not that much (e.g. can be done even with a 8 bit µC).
The simple digital RMS is also not that bad. On the positive side They could also work ok close to zero, with correct subtraction of it's own noise. They can be fast responding and no issue with lower frequencies.
The analog RMS chips have have to compromise between low frequency accuracy and response speed. Already the need to work well at mains frequency makes them a bit sluggish to respond. So accuracy usually drops, not much below 40 Hz.
So both ways have there pros and cons and a good digital implementation can outperform the old style analog in most aspects. Fast sampling could still add a bit to the power consumption.

Good higher frequency response would however also need compensation at the divider / input amplifier.
Somwhere in the kHz range is a cross over from the resistive to capacitive divider part. With several taps the compensation may not be easy.
So no need for the cheap RMS to work to much higher frequencies and limiting the frequency can reduce the noise.

[EEVblog]

For a modern DMM chip including digital RMS makes absolute sense. SD ADCs can work up to the audio range and the extra math to calculate the RMS result is not that much (e.g. can be done even with a 8 bit µC).

The interesting thing is the modern design Brymens don't even have a DMM chipset, it's just a micro with some analog functionality.

[Fungus]

The interesting thing is the modern design Brymens don't even have a DMM chipset, it's just a micro with some analog functionality.

It's the logical next step.

[mihaip]

Dave, thanks for all your work.

Are you planning a review of this multimeter ?
I'm quite interested in buying this instead of BM257s, but I want an expert opinion first.

Regards

[EEVblog]

Are you planning a review of this multimeter ?
I'm quite interested in buying this instead of BM257s, but I want an expert opinion first.

Maybe eventually, but if I'm going to sell it, then doesn't make sense to do a review unitl I have it in the store.
I've been using it and I haven't found any issues. Worth the bit extra over the BM235 IMO.

[Furna]

Are you planning a review of this multimeter ?
I'm quite interested in buying this instead of BM257s, but I want an expert opinion first.

Maybe eventually, but if I'm going to sell it, then doesn't make sense to do a review unitl I have it in the store.
I've been using it and I haven't found any issues. Worth the bit extra over the BM235 IMO.

So now the question is: when do you think to make a choice to sell it or not?
Also are you aware when Brymen is releasing it on the market?
Thank you

[EEVblog]

Also are you aware when Brymen is releasing it on the market?

One supplier was supposed to have stock end of this month I think.

[xKertx]

tme.eu has 4pcs in stock.

[mihaip]

From your experience do you guys think that first batch of a Brymen multimeter can have issues and I would better wait a while (how long) to get the BM2257?

Also Dave, what chip do you think is that BTCS26A. I could not find any 102 pin chip that matches.

Regards
Mihai

[J-R]

From your experience do you guys think that first batch of a Brymen multimeter can have issues and I would better wait a while (how long) to get the BM2257?

Also Dave, what chip do you think is that BTCS26A. I could not find any 102 pin chip that matches.

Regards
Mihai

The BM78x had a few minor issues at release that were slowly fixed over time.  Personally, I bought one of the early BM789 units and it has a few known issues.  The only issue I was able to fix myself was to install the shield over the speaker.  The other issues are in firmware and it would cost too much to try to get it updated by a dealer.

While the BM2257 appears to be an evolution of the BM257, it may have some new issues that will take time for buyers to discover.  So if that is a concern for you, then it is probably better to wait as long as possible before buying it.

[EEVblog]

From your experience do you guys think that first batch of a Brymen multimeter can have issues and I would better wait a while (how long) to get the BM2257?
Also Dave, what chip do you think is that BTCS26A. I could not find any 102 pin chip that matches.

I still use an original batch BM235 meter that's has like a half dozen firmware updates since then and it's fine. The updates are usually obscure stuff that most people will never encounter.

Sorry, can't tell you what the chip is, I'm under NDA.

[EEVblog]

FYI, I've ordered the BM2257 under my branding. Not sure if I'll continue to offer the BM235 long term as a result, but I still have a lot of stock left.

[J-R]

People will probably always be looking for both the BM235 and the BM2257, depending on what they do frequently.  There are quite a few differences.

[EEVblog]

People will probably always be looking for both the BM235 and the BM2257, depending on what they do frequently.  There are quite a few differences.

Exactly the same size and shape, the BM2257 just has some extra features. So apart from a relatively small cost difference, the BM2257 looks better in every regard.

[xKertx]

Got it!
Orange backlight is very nice, as is the very fine bargraph.

What about the viewing angle of the screen?
The 235 had contrast issues when viewed at angles. Have they improved that?
And are the digits the same size on both models? To my eyes the digits on 2257 looks slightly smaller on the photo.

[mihaip]

Can I update the Firmware myself on BM2257? Does Brymen publish fw updates?
I'm quite skilled with computers so it wouldn't be a problem for me.

[rsjsouza]

People will probably always be looking for both the BM235 and the BM2257, depending on what they do frequently.  There are quite a few differences.

Exactly the same size and shape, the BM2257 just has some extra features. So apart from a relatively small cost difference, the BM2257 looks better in every regard.

Being top of its range of general purpose compact meters, that is a meter that has very little compromises and it is the one to have IMO.

[Furna]

People will probably always be looking for both the BM235 and the BM2257, depending on what they do frequently.  There are quite a few differences.

Exactly the same size and shape, the BM2257 just has some extra features. So apart from a relatively small cost difference, the BM2257 looks better in every regard.

Being top of its range of general purpose compact meters, that is a meter that has very little compromises and it is the one to have IMO.

in blue

[EEVblog]

Got it!
Orange backlight is very nice, as is the very fine bargraph.

What about the viewing angle of the screen?
The 235 had contrast issues when viewed at angles. Have they improved that?
And are the digits the same size on both models? To my eyes the digits on 2257 looks slightly smaller on the photo.

Same 20mm digits.
Slightly less viewing angle above than one BM235 I tried, not very noticable.

[EEVblog]

Can I update the Firmware myself on BM2257? Does Brymen publish fw updates?
I'm quite skilled with computers so it wouldn't be a problem for me.

No, you can't. Only dealers can update the firmware.

[mihaip]

I still use an original batch BM235 meter that's has like a half dozen firmware updates since then and it's fine. The updates are usually obscure stuff that most people will never encounter.

Bummer that I can't update fw myself.
So how did you update the firmware of your BM235 if only the dealer can do it?

How are normal people like me update the firmware if there is something serious? Are they sending the meter back to the dealer?

Thanks all again for all your feedback !

[mihaip]

One more question: it seems it does not work well with Eneloops. BM2257 Low battery triggers at 2.5V, while BM257 at 2.3V. BM235 also 2.5V, so BM2257 would behave about the same as BM235 with Eneloops.

Any comments about this?

[EEVblog]

So how did you update the firmware of your BM235 if only the dealer can do it?

The BM235 is an older design with an OTP ROM, it can't be upgraded.

How are normal people like me update the firmware if there is something serious? Are they sending the meter back to the dealer?

Basically, you don't. No differen to countless other multimeters that have fixed firmware.

[Furna]

So how did you update the firmware of your BM235 if only the dealer can do it?

The BM235 is an older design with an OTP ROM, it can't be upgraded.

How are normal people like me update the firmware if there is something serious? Are they sending the meter back to the dealer?

Basically, you don't. No differen to countless other multimeters that have fixed firmware.

I can see more and more (young) people thinking fixed firmware is not accpetable.
@mihaip there are scenarios where a fixed firmware is the right choice. for a multimeter is a matter of where/what situation you use it

[rsjsouza]

So how did you update the firmware of your BM235 if only the dealer can do it?

The BM235 is an older design with an OTP ROM, it can't be upgraded.

How are normal people like me update the firmware if there is something serious? Are they sending the meter back to the dealer?

Basically, you don't. No differen to countless other multimeters that have fixed firmware.

I can see more and more (young) people thinking fixed firmware is not accpetable.
@mihaip there are scenarios where a fixed firmware is the right choice. for a multimeter is a matter of where/what situation you use it

Indeed. Especially if the hardware goes through revisions, which can be hard to track especially years after the initial releases.

[EEVblog]

I can see more and more (young) people thinking fixed firmware is not accpetable.
@mihaip there are scenarios where a fixed firmware is the right choice. for a multimeter is a matter of where/what situation you use it

Presumably that's why Brymen don't want to make it publicly available or even reference it's possible.
What percentage of multimeters on the market have publicly upgradable firmware? It's probably only a handful of meters.

[EEVblog]

Just got an email from Brymen saying the BM2257 uses an OTP ROM like the BM235.
So the programming port must just be for assembled PCB programming. Makes sense because the BM78x uses a header accessable through the battery compartment, but the BM2257 is internal.

[AVGresponding]

I can see more and more (young) people thinking fixed firmware is not accpetable.
@mihaip there are scenarios where a fixed firmware is the right choice. for a multimeter is a matter of where/what situation you use it

Presumably that's why Brymen don't want to make it publicly available or even reference it's possible.
What percentage of multimeters on the market have publicly upgradable firmware? It's probably only a handful of meters.

I can't imagine any do, that have (genuine) CAT ratings. Happy to be proved wrong though

[EEVblog]

What percentage of multimeters on the market have publicly upgradable firmware? It's probably only a handful of meters.

I can't imagine any do, that have (genuine) CAT ratings. Happy to be proved wrong though

My 121GW does, UL listing.
Fluke 289
I forgot the BM869s does
Keysight U1272A
Uni-T 181A

Basically only the high end high feature packed ones that have USB or SD card interfaces that make it easy.
I don't know of any low or mid range meters that do and rely on a factory micro programmer header.

[2N3055]

What percentage of multimeters on the market have publicly upgradable firmware? It's probably only a handful of meters.

I can't imagine any do, that have (genuine) CAT ratings. Happy to be proved wrong though

My 121GW does, UL listing.
Fluke 289
I forgot the BM869s does
Keysight U1272A
Uni-T 181A

Basically only the high end high feature packed ones that have USB or SD card interfaces that make it easy.
I don't know of any low or mid range meters that do and rely on a factory micro programmer header.

METRIX MTX3293 and whole that family of meters also have updatable FW and full listing.
Manufacturer guarantees changes in FW did not impact performance in a way that testing is invalidated.
In case it does, they need to retest and then new measurements apply to meters with new FW.

[rsjsouza]

What percentage of multimeters on the market have publicly upgradable firmware? It's probably only a handful of meters.

I can't imagine any do, that have (genuine) CAT ratings. Happy to be proved wrong though

My 121GW does, UL listing.
Fluke 289
I forgot the BM869s does
Keysight U1272A
Uni-T 181A

Basically only the high end high feature packed ones that have USB or SD card interfaces that make it easy.
I don't know of any low or mid range meters that do and rely on a factory micro programmer header.

METRIX MTX3293 and whole that family of meters also have updatable FW and full listing.
Manufacturer guarantees changes in FW did not impact performance in a way that testing is invalidated.
In case it does, they need to retest and then new measurements apply to meters with new FW.

The Keysight U1282A also has upgradable firmware. But updates were very minimal throughout the initial years and now they are non-existent. It is a mature product.

[Furna]

[...]
I forgot the BM869s does
[...]

I am not aware you can upgrade the firmware on BM869s; I own one and did some research on it before buying.
The only person I know about that was able to "upgrade" the firmware on BM869s was Joe Smith replacing the chip thus loosing the calibration.

[Kean]

I am not aware you can upgrade the firmware on BM869s; I own one and did some research on it before buying.
The only person I know about that was able to "upgrade" the firmware on BM869s was Joe Smith replacing the chip thus loosing the calibration.

Yes, and that required pre-programmed chips sent by Brymen (probably OTP parts).
That is not something they would normally do, but as I understood it Joe was helping them diagnose some issues he encountered.

[EEVblog]

[...]
I forgot the BM869s does
[...]

I am not aware you can upgrade the firmware on BM869s; I own one and did some research on it before buying.
The only person I know about that was able to "upgrade" the firmware on BM869s was Joe Smith replacing the chip thus loosing the calibration.

Ah, yes, I stand corrected.

[mihaip]

Since the fw of BM2257 is not updatable, I will wait until Dave will start selling it, so I'm confident that he tested it thoroughly and everything works fine and any early production bugs have been fixed.

[kwass]

I just received a BM2257 from TME and it's quite nice.

It love everything about this meter (you know the specs and at meets them all so not comments on that) it's very fast to auto range and test continuity (the best continuity tester I've can remember on any multimeter), great visibility, remembers some settings between power cycles, is small and feels just right in my hand, etc..  I have only two minor gripes: (1) - the diode test/beep is easily fooled by resistors in the range of 1K ohms, so make sure you're actually testing a diode and that it's out of circuit.  (2) - The autohold works great but when you diastole the button/warning beeps (hold RANGE when powering on) it disables the autohold beep.  It does not disable the continuity beep nor diode test beep, this seems inconsistent to me.

[SeoulBigChris]

How does this compare, physical enclosure size wise, to the 121GW and the BM-786? I can’t quite put my finger on it, but the 121GW always feels a little unbalanced to me. Even though I like the features of the 121GW best, I find myself reaching for the BM-786 more often than not, just because of the shape.

I have often wondered if the 121GW would benefit from a redesigned bail / stand. When I do use the 121GW, I usually figure out how to prop it up or lay it flat without extending the stand.

[EEVblog]

How does this compare, physical enclosure size wise, to the 121GW and the BM-786? I can’t quite put my finger on it, but the 121GW always feels a little unbalanced to me. Even though I like the features of the 121GW best, I find myself reaching for the BM-786 more often than not, just because of the shape.

Same as the BM235

[SeoulBigChris]

I read from the spec sheets, the 121GW is 60 mm thick and these others are 50 or 51 mm thick.

[EEVblog]

(2) - The autohold works great but when you diastole the button/warning beeps (hold RANGE when powering on) it disables the autohold beep.  It does not disable the continuity beep nor diode test beep, this seems inconsistent to me.

Cofirmed and reported to Brymen.

Also, when you release the probes after hearing the AutoHold beep in Ohms mode, the display resets and autoranges before displaying the captured reading. This is rather confusing. It doesn't do this in voltage mode. Also reported.

[EEVblog]

I read from the spec sheets, the 121GW is 60 mm thick and these others are 50 or 51 mm thick.

Yes, the 121GW had to be thicker because it uses AA batteries.

[EEVblog]

(2) - The autohold works great but when you diastole the button/warning beeps (hold RANGE when powering on) it disables the autohold beep.  It does not disable the continuity beep nor diode test beep, this seems inconsistent to me.

Cofirmed and reported to Brymen.
Also, when you release the probes after hearing the AutoHold beep in Ohms mode, the display resets and autoranges before displaying the captured reading. This is rather confusing. It doesn't do this in voltage mode. Also reported.

Brymen's response:

After checking, I found they are not bugs. They are their original design definitions.

When the AutoHold conditions are confirmed, the annuciator - "A-H" will flash to confirm that the reading is stable. The beep sound is just the auxiliary. That is the reason why its design disables beep simultaneously in the AutoHold function when beep is disabled. EEVblog BM786 has same AutoHold design definition for this.

The input signal may still change or fluctuate after AutoHold reading is got. To avoid misleading user, the AutoHold design displays all read-time readings (we call it as Real-ReadTM readings in manual) before ensuring the measurement is removed. That is the reason why there may be some intermediate display readings before the confirmed AutoHold reading is displayed. EEVblog BM786 has same AutoHold design definition for this too. Just because the inputs are different or the measurement responses of different functions are different, the intermediate display readings may be different.   

[rsjsouza]

You got to give many props for Brymen's interest in answering questions from the customer base.

[LinusSch]

Finally, some discussion on the 2257! I first saw this in May or so, on one of the Brymen websites. It eventually appeared on TME for preorder and for sale but until now I've seen no discussion, no comments from users or reviewers. I was starting to think I might have to bite the bullet and do that part myself. Alas, I'm out of funds for such things at the moment.

Riddle me this: why are all compact multimeters more or less low-end? The 121GW seems to be the only exception. The Fluke 110 series is very limited in functionality, perhaps most notably missing AutoHold which I think is a killer feature in many of the same situations where a compact meter is the one to have. The Keysight 1230 series do have AutoHold (with 10 measurements of memory, nice) but are still limited to three input jacks and the general sentiment seem to be that they are disappointing quality-wise. So... the Brymen 2250 series seems to me as if it has very limited competition.

Brymen's response:

After checking, I found they are not bugs. They are their original design definitions.

When the AutoHold conditions are confirmed, the annuciator - "A-H" will flash to confirm that the reading is stable. The beep sound is just the auxiliary. That is the reason why its design disables beep simultaneously in the AutoHold function when beep is disabled. EEVblog BM786 has same AutoHold design definition for this.

It is great that we get answers, this is a large reason that I hold Brymen as my preferred meter-making company!

To keep on updating the display until surely no reading, only then showing the hold value - that makes sense to me and is another of the reasons I felt good about buying my BM789. A rare occasion for sure, but if the meter is reading something when I don't expect it to I'm grateful that it would show me.

But to disable the AutoHold beep when disabling button beeps, this does not make sense to me.

The real value of the Hold feature is (to me) when you do not have eyes on the display while making the measurement. But it requires you to have a hand on the meter instead which may be equally impossible. AutoHold then makes it possible, on top of making easy what Hold makes cumbersome. Without AutoHold the solution is to have a second person reading the multimeter while the first person executes the difficult-to-reach probing. This probably never happens on a bench, but it is frustratingly common when working on a vehicle or similar.

If I was able to see an indicator on the display I could just as easily read the value without using Hold at all. Right? Unless my short-term memory is having an unusually bad day I don't think I see the point of Hold without a beep, Auto or not.

IME, YMMV, but definitely not a humble opinion in this case.

[EEVblog]

But to disable the AutoHold beep when disabling button beeps, this does not make sense to me.
The real value of the Hold feature is (to me) when you do not have eyes on the display while making the measurement. But it requires you to have a hand on the meter instead which may be equally impossible. AutoHold then makes it possible, on top of making easy what Hold makes cumbersome. Without AutoHold the solution is to have a second person reading the multimeter while the first person executes the difficult-to-reach probing. This probably never happens on a bench, but it is frustratingly common when working on a vehicle or similar.

Agreed, it's the entire point of AutoHold, you aren't looking at the display.

[0Anonym]

Hey,
Are there any updates on a possible release date or the development status?
Looking forward to it!

[EEVblog]

Are there any updates on a possible release date or the development status?
Looking forward to it!

My unit are due late December.
Brymen do not make and stock, they build to order.

[Furna]

Are there any updates on a possible release date or the development status?
Looking forward to it!

My unit are due late December.
Brymen do not make and stock, they build to order.

I guess we will have an announcemnt here on this forum topic (?)

[Furna]

My unit are due late December.
Brymen do not make and stock, they build to order.

It is now late December ... any update?
Thank you.

[BILLPOD]

I have often wondered if the 121GW would benefit from a redesigned bail / stand. When I do use the 121GW, I usually figure out how to prop it up or lay it flat without extending the stand.
[/quote]

    I took the rubbery boot off my 121GW and purchased a 3D printed stand that works
BEAUTIFULLY.  (I don't want to get in the 3D printing rabbit hole).

[EEVblog]

My unit are due late December.
Brymen do not make and stock, they build to order.

It is now late December ... any update?
Thank you.

There was a delay, now due mid Jan

[0Anonym]

Hey, its mid-January so just wanted to ask if there are any updates.
Also, to get one for sure I wanted to ask if its going to be available on Simons Electronics at launch or where Europeans should order instead.
Will the EEV Blog version come with the PC Adapter?

Thanks in advance.

[EEVblog]

Hey, its mid-January so just wanted to ask if there are any updates.
Also, to get one for sure I wanted to ask if its going to be available on Simons Electronics at launch or where Europeans should order instead.
Will the EEV Blog version come with the PC Adapter?

Stock turned up yesterday. Todays job is to get it on the store. PC serial adapter is separate.
It's up to Simon is he's going to sell it locally.

[Furna]

Hey, its mid-January so just wanted to ask if there are any updates.
Also, to get one for sure I wanted to ask if its going to be available on Simons Electronics at launch or where Europeans should order instead.
Will the EEV Blog version come with the PC Adapter?

Stock turned up yesterday. Todays job is to get it on the store. PC serial adapter is separate.

Do you work on Saturdays? Half past midnight now in Germany, will check the store in 8 hours

[EEVblog]

Do you work on Saturdays? Half past midnight now in Germany, will check the store in 8 hours

Not often, but I'm here today as rain has cancelled some kids stuff.

It's now on the store, but I have yet to do the manual and some other stuff ince the serial interface.
https://eevblog.store/products/eevblog-bm2257-multimeter

[Furna]

Do you work on Saturdays? Half past midnight now in Germany, will check the store in 8 hours

Not often, but I'm here today as rain has cancelled some kids stuff.

It's now on the store, but I have yet to do the manual and some other stuff ince the serial interface.
https://eevblog.store/products/eevblog-bm2257-multimeter

Sorry for your kids missing their open air time.
Having issue finalizing the order "No delivery available" 

[EEVblog]

Having issue finalizing the order "No delivery available" 

Odd. Can't see any issue on the listing compared to other products.
DM me your address so I can test it.

[EEVblog]

Having issue finalizing the order "No delivery available" 

Odd. Can't see any issue on the listing compared to other products.
DM me your address so I can test it.

I put a random addres in Germany and got the same message. Can you try another product, I want to see if it's the new product or not.
EDIT: I think it's the new product somewhow...

EDIT2: I think I fixed it, please try again!

[Furna]

Having issue finalizing the order "No delivery available" 

Odd. Can't see any issue on the listing compared to other products.
DM me your address so I can test it.

I put a random addres in Germany and got the same message. Can you try another product, I want to see if it's the new product or not.

I was able to finalize order #2252 *without* BM2257

[EEVblog]

I think I fixed it, please try again.
Stupid Shopify doesn't automatically add new products to the "physical store" 

[EEVblog]

I was able to finalize order #2252 *without* BM2257

Woah, you finalised the order without the meter?
If you did want the meter I'll have tro refund and cancel that order, is that what you want?

[Furna]

I think I fixed it, please try again.
Stupid Shopify doesn't automatically add new products to the "physical store" 

Order #2253 finalized with BM2257 included!

[Furna]

I was able to finalize order #2252 *without* BM2257

Woah, you finalised the order without the meter?
If you did want the meter I'll have tro refund and cancel that order, is that what you want?

I want #2252 + #2253
minus the double shipping expenses

[EEVblog]

I think I fixed it, please try again.
Stupid Shopify doesn't automatically add new products to the "physical store" 

Order #2253 finalized with BM2257 included!

Thanks. But the problem is now that you have paid for two separate shipping charges, and I can't manually add things. Let me cancel the 2251 order for the case and probes and I'll just include a case in the BM2257 order. The probes are already included, unless you need a spare set?

[EEVblog]

I was able to finalize order #2252 *without* BM2257

Woah, you finalised the order without the meter?
If you did want the meter I'll have tro refund and cancel that order, is that what you want?

I want #2252 + #2253
minus the double shipping expenses

I'll refund the shipping on the 2252 order and will ship as one lot. It gets messy.

[Furna]

I was able to finalize order #2252 *without* BM2257

Woah, you finalised the order without the meter?
If you did want the meter I'll have tro refund and cancel that order, is that what you want?

I want #2252 + #2253
minus the double shipping expenses

I'll refund the shipping on the 2252 order and will ship as one lot. It gets messy.

Got the refund already; thank you.
Sorry for the mess ... happy we figured it out.

Hope the rain at your place stops soon!

[mbarszcz]

Dave,

Do you know if the LoZ circuit is the same on the BM2257 as it was on the BM235?  After this interesting discussion: https://www.eevblog.com/forum/testgear/bm235-loz-mode/msg5734755/#msg5734755 I'm curious if the behavior has changed?

[rdenney]

@EEVBlog Dave, you mentioned (somewhere--now I can't find where) this was available on Amazon for a slightly higher price, and you provided a link from your YouTube video. But that link brings up the previous model BM235. Will the new model be supplied? I'm not sure I need yet another handheld DMM, but, of course, that's crazy talk.

Rick "always needs another DMM" Denney

[Furna]

@EEVBlog Dave, you mentioned (somewhere--now I can't find where) this was available on Amazon for a slightly higher price, and you provided a link from your YouTube video. But that link brings up the previous model BM235. Will the new model be supplied? I'm not sure I need yet another handheld DMM, but, of course, that's crazy talk.

Rick "always needs another DMM" Denney

The link to Amazon is on the EEVBlog shop page dedicated to the new BM2257
https://eevblog.store/products/eevblog-bm2257-multimeter
"Americans can now purchase the BM2235 though Amazon!"
and I confirm it brings up the "old" BM235

[floobydust]

Some confusion about the smaller mA/uA range fuse.
BM2257, BM2251 User's Manual (r3) specifies 0.63A fuse (ASTM HV620.0.63)
ASTM website only offer 0.6A fuse (HV620.0.6) and meter face is labelled 0.6A I guess for the range.

Dave can you comment if this is a custom part? Your store has the 0.4A part for the EEVblog BM235, BM786, and 121GW Multimeters.

[EEVblog]

Some confusion about the smaller mA/uA range fuse.
BM2257, BM2251 User's Manual (r3) specifies 0.63A fuse (ASTM HV620.0.63)
ASTM website only offer 0.6A fuse (HV620.0.6) and meter face is labelled 0.6A I guess for the range.
Dave can you comment if this is a custom part? Your store has the 0.4A part for the EEVblog BM235, BM786, and 121GW Multimeters.

It is supplied with a 630mA HV620 1000V fuse from ASTM. No part number on it because that's usually on the bulk box only.
So unless the normal 600mA is actually marked 630mA, yeah, it might be custom.
I can't see why given the BM235 and BM786 also have a 600mA range and use the 400mA fuse.
It's going to be annoying if I have to stock both.
I'll ask them.

[EEVblog]

@EEVBlog Dave, you mentioned (somewhere--now I can't find where) this was available on Amazon for a slightly higher price, and you provided a link from your YouTube video. But that link brings up the previous model BM235. Will the new model be supplied?

No, if you want the BM2257 you'll have the wait for the BM2257 listing which I haven't done yet. The old BM235 link is there because I copied the listing over.

[EEVblog]

Dave,
Do you know if the LoZ circuit is the same on the BM2257 as it was on the BM235?  After this interesting discussion: https://www.eevblog.com/forum/testgear/bm235-loz-mode/msg5734755/#msg5734755 I'm curious if the behavior has changed?

As mentioned here, it's different:
https://www.eevblog.com/forum/testgear/bm235-loz-mode/msg5723763/#msg5723763

I can measure a 1.5V battery at full 1mV resolution on the BM2257. Doesn't work at all on the BM235
I forgot that's an important difference to the BM235, so have added that to the listing.

[Kessler]

I just got my meter today ! I am a beginner and this is the first nice DMM I have had. Everything in the past has been cheap DMMs. Now off to go figure out what relay on my car is failing. 

[EEVblog]

Some confusion about the smaller mA/uA range fuse.
BM2257, BM2251 User's Manual (r3) specifies 0.63A fuse (ASTM HV620.0.63)
ASTM website only offer 0.6A fuse (HV620.0.6) and meter face is labelled 0.6A I guess for the range.
Dave can you comment if this is a custom part? Your store has the 0.4A part for the EEVblog BM235, BM786, and 121GW Multimeters.

It is supplied with a 630mA HV620 1000V fuse from ASTM. No part number on it because that's usually on the bulk box only.
So unless the normal 600mA is actually marked 630mA, yeah, it might be custom.
I can't see why given the BM235 and BM786 also have a 600mA range and use the 400mA fuse.
It's going to be annoying if I have to stock both.
I'll ask them.

Brymen replied and said the fuse is now 630mA because too many people questioned why a 400mA fuse (originally SIBA) was used in a 600mA range meter on the BM230 and BM780 series.
So with this new design BM2257 they submitted the meter with the ASTM 630mA fuse to UL and it was approved under IEC/EN/UL 61010-1/-2-033, so 630mA it is.
Why 630mA instead of 600mA? They didn't say, but the BM2257 does actually measure above 600mA in practice, so maybe they decided it would be nice to have a little over 600mA?

They can't retroactively change the BM230 and BM780 series to 630mA ASTM because technically it would require re-submitting the meter for UL approval again. And Brymen are super fussy about doing UL approval by the book.
Without a doubt the 600/630mA ASTM could also be used in the other models, but they can't officially say that.

[floobydust]

Limiting factor is the shunt resistor clamp-diodes, they must clear the fuse and never go open circuit.
Did you notice BM2257 they went overboard - five of 15A (350A 1/2 cycle surge) SMC parts - biggest diodes ever used there 
Not sure why Brymen upsized when everyone else has been using 1A (4007, M7) parts (Fluke, Agilent, BM235, 786, 857 and others) for many years.
It's great they are huge and safer, not likely to not care at all about clearing bigger fuses.

New regulatory testing costs a lot of money. To save lab time I will submit a few variants for testing at the same time.
Whatever meets spec and survives the tests gets put into the report, so you don't get locked in to using one specialty part.
BM235 pics showed 500mA Siba GZ DMI Prot, 70-172-40/0.5A so that series would likely work too, they have a 630mA part.

[Monkeh]

Some confusion about the smaller mA/uA range fuse.
BM2257, BM2251 User's Manual (r3) specifies 0.63A fuse (ASTM HV620.0.63)
ASTM website only offer 0.6A fuse (HV620.0.6) and meter face is labelled 0.6A I guess for the range.

Dave can you comment if this is a custom part? Your store has the 0.4A part for the EEVblog BM235, BM786, and 121GW Multimeters.

I'd bet money it's exactly the same fuse, they just put a different label on it because someone preferred less rounding (see: Renard series). I can't see the fuse wire being made to tolerances tight enough to actually differentiate at that level, 30mA is in the noise.

E: Then again, they do offer the 315mA and 400mA options, only 30mohm between them..

I wouldn't bat an eyelid at the difference if I needed a replacement, anyway.

[Gyro]

...
Why 630mA instead of 600mA? They didn't say, but the BM2257 does actually measure above 600mA in practice, so maybe they decided it would be nice to have a little over 600mA?
...

Because 630mA is an industry standard value (like 3.15A for instance). Look on a main distributor site and you will find a couple of 600mA fuses but dozens of 630mA.


Edit: Snap.

[mwb1100]

SIBA 7017240 comes in a 630mA SKU that should be an equivalent to the ASTM part:

  - SIBA 7017240.0,63 630mA 1000V  IR 30kA  (6 x 32mm)

The SIBA fuses aren't too hard to find at a reasonable price.

  - https://www.aliexpress.us/item/3256806238128876.html  (if you trust Aliexpress seller) $12 for 10, shipping included
  - https://www.aliexpress.us/item/3256802828651015.html  (if you trust Aliexpress seller) $20 for 20, shipping included

A more trustworthy vendor (but I don't know what the shipping would be):

  - https://www.tme.eu/en/details/zgssh-0.63a/fuses-6-3x32mm-super-fast/siba/7012540-0-63/  $3 each

The 500mA variant is even easier to find and might make an acceptable replacement.

[Furna]

SIBA 7017240 comes in a 630mA SKU that should be an equivalent to the ASTM part:

  - SIBA 7017240.0,63 630mA 1000V  IR 30kA  (6 x 32mm)

  - https://www.tme.eu/en/details/zgssh-0.63a/fuses-6-3x32mm-super-fast/siba/7012540-0-63/  $3 each

For the 11A I am thinking this one DMM-B-11A https://www.welectron.com/mediafiles/datasheets/cooper-bussmann/Cooper-Bussmann_DMM-B_Datasheet.pdf

[mwb1100]

Yes, the 11A fuse in Brymen meters is the same as the Fluke 11A fuse - any Bussman DMM-11, DMM-B-11 or DMM-B-11-r will work.  Also the Littlefuse FLU011 or FLU 11A (I think any 11A Littlefuse with an ID that begins "FLU" will be interchangeable).  These fuses are generally easy to find, but seller's asking price varies widely.  You should be able to find one for around $10 or less without trouble, which looks like Welectron's price.

[Furna]

As soon as my BM2257 arrives, I will take it apart to honour the EEVBlog motto ... and if it really contains an Bussmann KLM-12 I will remove and sell it on EBay
It is 76€ on DigiKey.
That is ridiculos
 

[mwb1100]

[Bussman KLM-12] is 76€ on DigiKey.

Mouser is similar pricing...  everyone else is a more sane $10 each give or take (and I'm not convinced that they are fakes).  I'd bet that the Digikey/Mouser pricing is a mistake where they are quoting the boxed units of 10 as "Quantity 1".  Of course anyone ordering should confirm that with them and have the pricing fixed before ordering.

By the way, what makes you think the BM2257 might come with a KLM-12?  Dave's photos showed the ASTM HV110.

[Furna]

[Bussman KLM-12] is 76€ on DigiKey.

Mouser is similar pricing...  everyone else is a more sane $10 each give or take (and I'm not convinced that they are fakes).  I'd bet that the Digikey/Mouser pricing is a mistake where they are quoting the boxed units of 10 as "Quantity 1".  Of course anyone ordering should confirm that with them and have the pricing fixed before ordering.

By the way, what makes you think the BM2257 might come with a KLM-12?  Dave's photos showed the ASTM HV110.

I checked only DigiKey and Mouser ...
Pag 16 of the manual mentions Bussmann or ASTM (in this order).
I guess ASTM is cheaper than Bussmann so Braimen will use Bussmann only in case of shortages.

[mwb1100]

Pag 16 of the [BM2257] manual mentions Bussmann [KLM-12] or ASTM [HV110.11A] (in this order).

Interesting...  I didn't notice that when browsing the manual. Seems a little strange to specify the unusual Bussman KLM-12 (which is 12A/600V) instead of the DMM-11 which pretty much every handheld multimeter in this class uses.  The Bussman DMM-11 has the same specs as the ASTM H110.11A except that the IR rating of ASTM's is 30kA versus the DMM-11's 20kA (the KLM-12 has IR 50kA).

[EEVblog]

By the way, what makes you think the BM2257 might come with a KLM-12?  Dave's photos showed the ASTM HV110.

I checked only DigiKey and Mouser ...
Pag 16 of the manual mentions Bussmann or ASTM (in this order).
I guess ASTM is cheaper than Bussmann so Braimen will use Bussmann only in case of shortages.

My BM2257 stock has ASTM for both.
I'm the one that found and introduced Brymen to ASTM, they used to use SIBA. It seems that they may have now standardised on them, and yes, that would be because of cost. The ASTM's are very cost effective when you buy in bulk. I buy thousands at a time.

[EEVblog]

Limiting factor is the shunt resistor clamp-diodes, they must clear the fuse and never go open circuit.
Did you notice BM2257 they went overboard - five of 15A (350A 1/2 cycle surge) SMC parts - biggest diodes ever used there 
Not sure why Brymen upsized when everyone else has been using 1A (4007, M7) parts (Fluke, Agilent, BM235, 786, 857 and others) for many years.
It's great they are huge and safer, not likely to not care at all about clearing bigger fuses.

I suspect it's because they knew they were going for a bigger fuse rating for UL testing so they went full belt'n'braces to make sure. They are monsters.

[EEVblog]

Now it's got me wondering if I have to now stock two different fuses (400mA + 630mA) or standardise on either 400mA or 630mA for all meters (BM2257, BM235, BM786, 121GW) 

Obviously the 400mA will work in all, but the 630mA is technically not UL rated for the other meters apart from the BM2257, but of course in practice it will work just fine and be safe for all the 600mA range meters.

[mwb1100]

I buy thousands at a time.

Wow!

Now it's got me wondering if I have to now stock two different fuses (400mA + 630mA) or standardise on either 400mA or 630mA for all meters (BM2257, BM235, BM786, 121GW) 

Maybe change the package to:


    2 x HV110 11A 30kA 1000V HRC (10x38mm)
    2 x HV620 400mA 10kA* 1000V HRC (6x32mm)
    3 x HV620 630mA 10kA* 1000V HRC (6x32mm)

* the ASTM data sheet says H620 fuses are "Self-certified for Breaking Capacity 30kA @ 1000VAC/DC for 800mA and below"

The datasheet also doesn't mention a 630mA H620 fuse, but since Brymen is installing them I'm guessing it is available to the likes of someone who buys thousands.

I'd guess a package like that would make as many people happy as unhappy, making it a wash happinesswise.  People who want to go by-by-the book would be able to and would have a couple "not by-the-book" spares to get them by in a pinch if need be (or forever if they eased up).  No idea how much more trouble it'd be for you.

[EEVblog]

I'd guess a package like that would make as many people happy as unhappy, making it a wash happinesswise.  People who want to go by-by-the book would be able to and would have a couple "not by-the-book" spares to get them by in a pinch if need be (or forever if they eased up).  No idea how much more trouble it'd be for you.

It's trouble either way, guaranteed!
I think the mixed bag is probably a good idea.

[Kleinstein]

The 11 A fuse rarely blows. On the other side the 400/600 mA fuses may blow from time to time. They are really fast and I manged to blow one from inrush current to some electrolytic capacitors.

I would not mind the 600/630 mA difference very much, but the 400 mA fuse is still sufficiently different. It's the users to decide if they want a slightly more robust fuse or the original rating. Chances are it would be better to offer both sizes. There may also be owners of other meters that are looking for a spare fuse. I don't think a mixed bag would make much sense - one either wants the safe / certified way or the slightly more robust version. For those meters that specify 600 mA, very few would settle for a 400 mA fuse.

[EEVblog]

The 11 A fuse rarely blows. On the other side the 400/600 mA fuses may blow from time to time. They are really fast and I manged to blow one from inrush current to some electrolytic capacitors.

That's why my mixed bag has 2 x 11A and 5 x 400mA

I would not mind the 600/630 mA difference very much, but the 400 mA fuse is still sufficiently different. It's the users to decide if they want a slightly more robust fuse or the original rating. Chances are it would be better to offer both sizes. There may also be owners of other meters that are looking for a spare fuse. I don't think a mixed bag would make much sense - one either wants the safe / certified way or the slightly more robust version. For those meters that specify 600 mA, very few would settle for a 400 mA fuse.

Either way I've just ordered 1000 of both.
I might just offer two different mixed bags. Although I can see the emails now "you sent me the 400mA and I wanted the 600mA"

[mihaip]

Dave, when will you get new stock of BM2257 ?

[Fungus]

Pop quiz: How many mA does it take to blow a 400mA fuse?

[geralds]

Hi, I am new to electronics, and new to this forum - thus apologies if I am missing any convention (or if I am posting in the wrong thread).

I need a DMM for electronics repairs, primarily home electronics (laptops, hifi equipment, possibly some dehumidifiers, etc.). I have been looking at the BM2257, mainly because of the reviews and comments by Dave and others on this blog. Alternatives in my selection are AN870, ZT219, and H118E (though not my preference as they seem to be less solid and less accurate?). Or the Fluke 115 as a set with TLK-225-1 as this seems to be on promotion at the moment (but I understand functionality may be less than the BM2257?).

Against this backdrop / intended use, would the BM2257 be fit for purpose? Would you recommend another DMM? BM2257 is more or less top end of my intended budget. Fluke 115 cost more, but it already has the test lead set included (which I would need to add to the price of the BM2257 for a fair comparision). I would rather spend this money on the BM or the Fluke if the higher quality justifies when compared with the cheapos.

Many thanks for your help and input,
Gerald

[EEVblog]

Hi, I am new to electronics, and new to this forum - thus apologies if I am missing any convention (or if I am posting in the wrong thread).
I need a DMM for electronics repairs, primarily home electronics (laptops, hifi equipment, possibly some dehumidifiers, etc.). I have been looking at the BM2257, mainly because of the reviews and comments by Dave and others on this blog. Alternatives in my selection are AN870, ZT219, and H118E (though not my preference as they seem to be less solid and less accurate?). Or the Fluke 115 as a set with TLK-225-1 as this seems to be on promotion at the moment (but I understand functionality may be less than the BM2257?).
Against this backdrop / intended use, would the BM2257 be fit for purpose? Would you recommend another DMM? BM2257 is more or less top end of my intended budget. Fluke 115 cost more, but it already has the test lead set included (which I would need to add to the price of the BM2257 for a fair comparision). I would rather spend this money on the BM or the Fluke if the higher quality justifies when compared with the cheapos.

Welcome to the forum.
I might be biased, but the BM2257 is probably the most feature packed you will get the for the price in a top brand. Plenty for electronics and home repair. The Fluke 115 is an excellent meter, but doesn't have the handy EF function or TouchHold.
Both are plenty for home electronics and repair use.
THat being said, there might technically be better bang-per-buck to be had in the lower priced tools like the AN870, which would also suit your purpose.
https://www.eevblog.com/forum/testgear/looking-at-three-very-different-multimeters-(aneng-an870-and-eevblogs-meters)/
You can get cheap probe adapters of various sorts from Aliexpress if you need those. e.g.
https://youtu.be/tz4cYPj3Kls?si=LWfqDO8283CIK-V7&t=864

[mwb1100]

I have been looking at the BM2257, mainly because of the reviews and comments by Dave and others on this blog.

The BM2257 is very newly released.  As far as I know it hasn't been reviewed by anyone, more or less just comparisons of the specs and build when compared to the BM235 (and to a lesser extent the BM257s).  It's expected that the BM2257 will  perform and have a robustness similar to the BM235/BM257s.  I believe it has all of the features of the BM235 and the BM257s plus more.  The specs are very similar, but there are some differences - minor ones in my opinion.

Probably the biggest features over the BM235 are PC connectivity, which requires an additional purchase of a interface cable, (the BM257s also had PC connectivity) and autohold.

The BM2257 look like it will cost about $25 - $40 more than BM235. I think the consensus is that the BM235 is considered a pretty good value considering design and build quality and feature set.  I'd expect the BM2257 to be similarly regarded, but that's just my expectation, but it is at a higher price point.

The Fluke 115 looks to have a similar feature set to the BM235 (i haven't done a point-by-point analysis of the datasheets though), but costs more than twice as much.

The other meters you mention are significantly less expensive, and are probably a better way to go when starting out.  After using them for a while you'll have a much better idea of what you might be willing to pay  more for. They should be pretty darn accurate, where they might be lacking is in robustness and safety.  For electronic work those aren't too much an issue, for mains work opinions differ.

[EEVblog]

Pop quiz: How many mA does it take to blow a 400mA fuse?

In theory, 401mA after quite some time.
At 400mA the fuse should not break after an infinite time.
In practice, any random value if you bought a fake off ebay, or if genuine follow the parametric charts and add your own window, add salt to flavour.

[EEVblog]

Dave, when will you get new stock of BM2257 ?

Stock keeping error, I have them, check again.

[Furna]

Dave, when will you get new stock of BM2257 ?

Gemini:
A 400mA fuse is designed to blow when the current flowing through it exceeds 400 milliamperes (mA).

**Therefore, it takes slightly more than 400mA to blow a 400mA fuse.**

* **Note:** The exact current required to blow the fuse can vary slightly depending on factors like the fuse's specific design, age, and operating temperature.

[mwb1100]

Pop quiz: How many mA does it take to blow a 400mA fuse?

Depends on the fuse.

According to this datasheet for the SIBA 7017240, a fuse which has been used in Brymen meters and other fast blow ceramic fuses used in meters might be similar to:

  - at 400mA the fuse will last at least 1 hour, but could (and should) last much longer
  - at 1.6A the fuse will blow within  60 ms
  - at  4A the fuse will blow within 6 ms

(assuming I'm reading the table and chart correctly)

[bdunham7]

I need a DMM for electronics repairs, primarily home electronics (laptops, hifi equipment, possibly some dehumidifiers, etc.). I have been looking at the BM2257, mainly because of the reviews and comments by Dave and others on this blog. Alternatives in my selection are AN870, ZT219, and H118E (though not my preference as they seem to be less solid and less accurate?). Or the Fluke 115 as a set with TLK-225-1 as this seems to be on promotion at the moment (but I understand functionality may be less than the BM2257?).

If your budget allows it, avoid the low-end stuff.  Either the Fluke or Brymen will be good. 

What is the promotion Fluke is offering? Fluke stuff is expensive, especially in Europe so waiting for a sale is wise. I'd actually recommend you look at the 116 plus maybe a current clamp.  A while back I got such a set on promotion with a pretty good set of leads, case, etc.  It might seem strange not having a current range, but since the 115 only has a 10A range anyway I don't think you're losing much.  You don't want to be running mains current through the meter like that.  Since you say you're a novice, the 116 has the advantage that it is literally impossible to blow it up by connecting it wrong to any voltage you'll find in your household--except the microwave oven and please don't ever open that up if you don't know exactly what you are doing (and best not even then).  The 116 and BM2257 also have a Low-Z mode that you may not understand at the moment but is IMO a very valuable feature.

If you want good test leads, look at ProbeMaster.  Also, I believe if you buy the Brymen BM2257 from the EEVBlog store you get some pretty good test leads in the package.  The TLK-225 set is nice stuff, but geared more towards industrial electricians.  I have some of those probes and clamps and don't use them all that often.  It seems a bit odd to offer them with the 115 because they're more something you'd use with a 179, 87-V or 287 since those are CATIII/1000V meters. 

[tautech]

Pop quiz: How many mA does it take to blow a 400mA fuse?

In theory, 401mA after quite some time.
At 400mA the fuse should not break after an infinite time.
In practice, any random value if you bought a fake off ebay, or if genuine follow the parametric charts and add your own window, add salt to flavour.

Good topic for a video.

Quality vs no name vs Normal vs Slow blow vs Fast blow.
 

[EEVblog]

Pop quiz: How many mA does it take to blow a 400mA fuse?

In theory, 401mA after quite some time.
At 400mA the fuse should not break after an infinite time.
In practice, any random value if you bought a fake off ebay, or if genuine follow the parametric charts and add your own window, add salt to flavour.

Good topic for a video.
Quality vs no name vs Normal vs Slow blow vs Fast blow.

It would be, except it's basically a statistical thing, so you have to run a lot of them.

[mwb1100]

It would be, except...

But what's more popular than a YT where things blow up?

(though fuses popping might not be so exciting)

[EEVblog]

It would be, except...

But what's more popular than a YT where things blow up?
(though fuses popping might not be so exciting)

Sadly you don't get to see anything with sand filled HRC fuses

[mwb1100]

Sadly you don't get to see anything with sand filled HRC fuses

of course...   

[geralds]

@eevblog, @mwb1100, @bdunham7 (not sure whether "@" + user works like in Outlook?)

Many thanks for your super fast replies, which are very helpful indeed! What a forum!

I will then look again at the AN870, despite my tendancy for the BM2257 as it seems more robust and thus should hopefully last substantially longer. Plus a set of ProbeMaster and Hirschmann leads/probes.

Re Fluke 115/225 set, there seems to be a promotion in Europe for around EUR 250. But noted about (lack of) Auto-Hold function, LoZ and usefulness about probes/test leads for electronics, so it seems the BM2257 has more useful features/functions for my requirements. And the promotion/set does not seem to be available for the 116/117.

I have no intention to do any mains works (nor microwave ovens!) - I know my limits and prefer to leave that work to the professionals.

I will keep you posted once I have finally decided (may take a few weeks).

Thanks again, your response time and helpfulness is really impressive!

[tautech]

Pop quiz: How many mA does it take to blow a 400mA fuse?

In theory, 401mA after quite some time.
At 400mA the fuse should not break after an infinite time.
In practice, any random value if you bought a fake off ebay, or if genuine follow the parametric charts and add your own window, add salt to flavour.

Good topic for a video.
Quality vs no name vs Normal vs Slow blow vs Fast blow.

It would be, except it's basically a statistical thing, so you have to run a lot of them.

Apply KISS principles as to many new entrants a fuse is just a fuse.

[EEVblog]

I forgot I had done this video!

[bdunham7]

(though fuses popping might not be so exciting)

I just finished the first round with the fuses you sent me.  You're right, it's not that exciting.   

[jj5]

Maybe change the package to:

    2 x HV110 11A 30kA 1000V HRC (10x38mm)
    2 x HV620 400mA 10kA* 1000V HRC (6x32mm)
    3 x HV620 630mA 10kA* 1000V HRC (6x32mm)

I think that's a great idea. This set would suit me as I have a BM2257 and am planning to get 121GW and maybe some others. Not sure how much it would suit others though!

[jj5]

I think that's a great idea. This set would suit me as I have a BM2257 and am planning to get 121GW and maybe some others. Not sure how much it would suit others though!

p.s. I would also be happy to buy one 11A+400mA set plus one 11A+630mA set.

[Fungus]

Against this backdrop / intended use, would the BM2257 be fit for purpose?

Easily.

[CustomEngineerer]

From the bm235-loz-mode thread:

FYI, the new BM2257 will autorange down to 6V range in LowZ mode, so you get the full 1mV resolution all the way down to 0V.
Completely changed from the BM235

Wondering if anyone has anyone tested this? The user manual suggests LoZ only works down to 1.5V. Testing on mine it seems to work down to about 0.930V. If I'm not reading to much into the above quote it seems Dave is suggesting it goes all the way down to 0V? Or maybe he just meant that you get the full 1mV resolution until it cuts out, which it does. Not a big deal either way, but was curious if I was missing something.

This is what the BM2257 user manual has to say about it.

When a signal above the voltage threshold of 1.5V DC or AC up to the rated 600V is present, the meter displays the voltage value in the appropriate type DC or AC, whichever is larger in peak magnitude.

[EEVblog]

From the bm235-loz-mode thread:

FYI, the new BM2257 will autorange down to 6V range in LowZ mode, so you get the full 1mV resolution all the way down to 0V.
Completely changed from the BM235

Wondering if anyone has anyone tested this? The user manual suggests LoZ only works down to 1.5V. Testing on mine it seems to work down to about 0.930V. If I'm not reading to much into the above quote it seems Dave is suggesting it goes all the way down to 0V? Or maybe he just meant that you get the full 1mV resolution until it cuts out, which it does. Not a big deal either way, but was curious if I was missing something.

This is what the BM2257 user manual has to say about it.

When a signal above the voltage threshold of 1.5V DC or AC up to the rated 600V is present, the meter displays the voltage value in the appropriate type DC or AC, whichever is larger in peak magnitude.

I stand corrected. Just measured one and only got down to 0.93V.
In practice, that's plenty low.

[CustomEngineerer]

Agreed, thanks for verifying. Hope a few others do as well just to see if the 0.93V is consistent.

[Furna]

I just received mine today ...
I can go down to 0.928V
The image has been captured when it was at 0.929V but I can guarantee 0.928V
Sorry for the low quality photo.

Super happy!

Actually for the low amp fuse I went for EKSA 632.415 630mA
Sorry Dave I didn't buy the fuse from you; at the time of the order you only had the 600mA

[bdunham7]

I stand corrected. Just measured one and only got down to 0.93V.
In practice, that's plenty low.

It would be interesting to know what design quirk makes it work that way as I don't see an obvious reason for it on DCV.  Is the input impedance still low below 0.93V?

[EEVblog]

Actually for the low amp fuse I went for EKSA 632.415 630mA
Sorry Dave I didn't buy the fuse from you; at the time of the order you only had the 600mA

I've ordered 630mA fuses from ASTM but have not heard anything back yet. Resent the email to new people and still nothing. Not sure what's going on...

[floobydust]

I stand corrected. Just measured one and only got down to 0.93V.
In practice, that's plenty low.

It would be interesting to know what design quirk makes it work that way as I don't see an obvious reason for it on DCV.  Is the input impedance still low below 0.93V?

What are we talking about?  I got lost here.
That there is a deadzone of +/-0.93V before a reading is displayed, or for the LowZ load to engage? The Brymen manual does not say what happens below "1.5V".
You found the transistor clamp are in-series with the LowZ PTC load (on a different Brymen model) so nothing much is happening at below say 6V for the input impedance to decrease on them. (There may be a MOV-like action with these HV PTC's, as a faint theory of mine, as they have similar construction.)


As far as the fuses go, I see very little difference from 500-630mA when the relevant BM2257 range is 600mA.
Those fuses don't even consider blowing until currents are 2-4x times above that, and the i²t times are not so different.

[bdunham7]

What are we talking about?  I got lost here.
That there is a deadzone of +/-0.93V before a reading is displayed, or for the LowZ load to engage? The Brymen manual does not say what happens below "1.5V".

Well, both and how they might be related.  The BM2257 auto-ranges down and I'm really curious to know why it would not read below 0.93V just because there is a PTC across the inputs.  I'm presuming it is because the input layout just isn't that simple.  The input impedance issue is just another angle that might give a clue as to the input setup.  It just seems a bit...weird.

Fluke's straightforward approach means it will read down to the last digit in DC Lo-Z, although it only has a 1000V range.  And the input impedance is about 3.2k no matter how little the input voltage is.

[Furna]

Is the input impedance still low below 0.93V?

Ohm's law says at 2V impedance is around 2KΩ (see picture).
For lower voltages I get unreliable A values.

[EEVblog]

What are we talking about?  I got lost here.
That there is a deadzone of +/-0.93V before a reading is displayed, or for the LowZ load to engage? The Brymen manual does not say what happens below "1.5V".

Well, both and how they might be related.  The BM2257 auto-ranges down and I'm really curious to know why it would not read below 0.93V just because there is a PTC across the inputs.  I'm presuming it is because the input layout just isn't that simple.  The input impedance issue is just another angle that might give a clue as to the input setup.  It just seems a bit...weird.

Yeah, I'm surprised.
I can understand the BM235 with the input arrangement it uses, but this is a bit puzzling. Sounds dual diode droppy...

[floobydust]

If there is a deadzone for the LowZ to engage - then I'd need to know about it and probably say ick.
It sounds like input impedance is 10MEGΩ when input voltage is less than 2-3 diode drops, and above that the PTC is present and 2.1kΩ when LowZ is selected. It does simplify the rotary switch design and that is why I think Brymen is doing it.
To test/prove it you could inject a sine-wave with series sense resistor observed on a scope, to see if this is the case.

This will cause a problem when troubleshooting low voltage such as automotive. You'll get say a 1.5V ghost reading outside of the pristine laboratory, in the mud and dirt.
Do the armchair experts here know what this means? 

[bdunham7]

It sounds like input impedance is 10MEGΩ when input voltage is less than 2-3 diode drops, and above that the PTC is present and 2.1kΩ when LowZ is selected. It does simplify the rotary switch design and that is why I think Brymen is doing

I don't think there's that sort of direct correlation between the input impedance and the minimum reading.  Does the BM235 stop reading below about 7V or does it just go high-impedance?  Those really are somewhat independent issues although the design may work in some sort of relation between the two.  Dave just needs to break out a screwdriver and have a look....

[EEVblog]

I don't think there's that sort of direct correlation between the input impedance and the minimum reading.  Does the BM235 stop reading below about 7V or does it just go high-impedance?  Those really are somewhat independent issues although the design may work in some sort of relation between the two.  Dave just needs to break out a screwdriver and have a look....

In progress...

[Furna]

One of the armchair experts here, doesn't have (yet) an AWG ... it's on the buy list althought not on the top.
 

[floobydust]

   It would be great if we knew the two PTC part numbers, somebody cut off the heatshrink tubing over them to see that.
I also note Fluke ditched using clamp transistors for a while now in their newer models and instead is using diode arrays but they are not symmetrical. Clamp is +6V_f and -2V_f on the (PTC) Ohm's source channel and Dave might see something odd like that if Brymen is indeed running the LowZ PTC in series with a clamp.
I could draw the BM2257 schematic if I had one or loosely based on board pics but that would cause trouble.

Hey this is new silicon? Brymen got the (Hycon) LCD driver and DMM IC into one 100-pin package it seems.

[bdunham7]

I also note Fluke ditched using clamp transistors for a while now in their newer models and instead is using diode arrays but they are not symmetrical.

Fluke has newer models?

The 87V does appear to be BAV199s.  IDK about the small meters, but on the 289 it appears they just can't make up their mind which to use.

[floobydust]

I consider the 87 an old dog, I love her dearly. Just a model number number Fortive keeps rehashing. That transistor clamp design goes back to at least 1989 in the Fluke 87, I don't consider it recent. Hand-selected parts and you don't know what their BV_EBO ends up, is it 5V or 7V or 10V etc. depending on batch and manufacturer.
A 7V spike into a DMM IC is not really a good idea, still too much. The days of 9V battery-powered multimeter (IC's) are gone as well, today the IC's are lower voltage. People are just copying the old design I think.

I was talking about for example, the Fluke 107 and 17B schematics. It's a diode party of BAV199, they must survive the few amp transient test impulse. The Fluke 107 Joeqsmith seemed to like its robustness, uses no transistor clamp scheme that I know of.  (The 17B transistor clamp circuit is a bit over my head unless I get some coffee).

BM2257 using SOT-23 diodes array? "N" marking code not sure what they are. Clamp transistors appear to be 2SC5866 "VLR" 6V but high leakage current.
Hopefully Dave will reveal the Brymen LowZ issue at hand. 121GW is just a switch to engage the PTC, no drama.

[Fungus]

Edit: Post removed - something mixed up in the system and that was about Uni-T.

[floobydust]

Very few are 600V or 1,000V rated, and even fewer have approvals. Hard to find them and see their datasheets.

[EEVblog]

  It would be great if we knew the two PTC part numbers, somebody cut off the heatshrink tubing over them to see that.

I doubt there's anything special about them.
Probably the most generic PTCs possible, whatever was cheap in Shenzhen that day.

The small one has no marking. I'll cut the heatshrink off the bigger one, but I suspect it's also unmarked.
Brymen don't substitute parts that I know of, so they would have a specific brand and model specced in.

[Fungus]

I doubt there's anything special about them.

Probably the most generic PTCs possible, whatever was cheap in Shenzhen that day.

There may not be anything special about them, but I doubt Brymen is sourcing gray market parts.

Post removed - something glitched in the system. Of course Brymen don't buy Shenzhen specials.

[EEVblog]

BM2257 using SOT-23 diodes array? "N" marking code not sure what they are. Clamp transistors appear to be 2SC5866 "VLR" 6V but high leakage current.
Hopefully Dave will reveal the Brymen LowZ issue at hand. 121GW is just a switch to engage the PTC, no drama.

Unless I missed something in my reverse engineering, the LowZ input shunts PTC2 (bigger one, also unmarked under the heatshrink) and R32 (1K) directly to COM, and then going through R33 (1k) and PTC1 (smaller one), clamped with VAR2 and VAR1 to COM. Then through the HV 10M directly to pin 26 of the BTC chip. No extra protection.
So anything that's happening here is happening inside the chip.

The "VLR" SOT-23 clamps are only used in Ohms mode. Q10+Q11 in parallel with Q7+Q8.

Edit: I missed the other side of the switch in Low-Z, but it wasn't in the input signal path, will trace it.

[bdunham7]

Can someone post a photo of their BM2257 in Low-Z mode with less than 0.928VDC on the input? 

[EEVblog]

Can someone post a photo of their BM2257 in Low-Z mode with less than 0.928VDC on the input?

It doens't display anything, just kinda flashed a bit IIRC, as if it was glitch reading or something.

[bdunham7]

Unless I missed something in my reverse engineering, the LowZ input shunts PTC2 (bigger one, also unmarked under the heatshrink) and R32 (1K) directly to COM, and then going through R33 (1k) and PTC1 (smaller one), clamped with VAR2 and VAR1 to COM. Then through the HV 10M directly to pin 26 of the BTC chip. No extra protection.
So anything that's happening here is happening inside the chip.

That sounds like what I'd expect there to be and the impedance should be ~2.2k all the way to zero.

I think maybe the answer is that the Auto-V switch logic that decides whether the display should be AC or DC may have a threshold or multiple thresholds.  When you supply it with less than the 0.928V and it shows all zeros, does it display the AC or DC symbol?  And where is the decimal point?

Edit:  our posts crossed in web continuum

It doens't display anything, just kinda flashed a bit IIRC, as if it was glitch reading or something.

So an Auto-V threshold makes sense then.  Next question:  How low will it go on ACV @ 50/60Hz?

[EEVblog]

So an Auto-V threshold makes sense then.  Next question:  How low will it go on ACV @ 50/60Hz?

Good point, I'll try it.

[EEVblog]

Edit: I missed the other side of the switch in Low-Z, but it wasn't in the input signal path, will trace it.

Nope, it's just physically switching the backlight in OFF mode. Seems odd, maybe reducing quiescent, or maybe backfeeding through the chip during power down or something.

[5U4GB]

Pop quiz: How many mA does it take to blow a 400mA fuse?

If it's a Chinese blade fuse you bought off Amazon, about 20 amps.

[Furna]

So an Auto-V threshold makes sense then.  Next question:  How low will it go on ACV @ 50/60Hz?

Good point, I'll try it.

I measured 0.9 ACV @50Hz

[kwass]

I get the same 0.900 V on 60Hz AC and a lower limit of 0.916 V on DC.

BTW the AUTO DC volts is useful for testing small coin cells as the load is typical of many devices they are used in.

[bdunham7]

Good point, I'll try it.

I think this "glitch", if it even can be called that, could likely be corrected improved in the firmware.  I was curious as to how my only Auto-Check Low-Z meter, the Fluke 116, handles mixed signals or AC with a DC offset as well as small voltages--so I checked.  It seems that the way the 116 handles it is to default to DCV (reads 0.0V DC with no input) and then measure and display the DC coupled RMS (aka TRMS AC + DC) value in all cases and either the AC or DC symbol depending on the mix.  Again, it appears to default to DC and then only displays the AC symbol instead if the AC component is signficantly higher than the DC component.  For example, 100mVAC and 200mVAC both display as 0.1 VDC and 0.2 VDC respectively, while 300mV displays as 0.3VAC.  I didn't test this extensively to see what the exact relationship was, but the AC component consistently needs to be significantly higher to get the AC displayed, at least at the lower levels.  Perhaps at higher voltages the thresholds will be relatively closer. 

IDK how the Brymen system works internally and we probably will never know, but very possibly if they just had it default to DC whenever the inputs are low enough that the circuitry can't decide otherwise then it would read smoothly to zero.  If these meters were really smart they would display both the AC and DC symbols when relatively significant components of either are present.  But maybe they just ran out of program memory space.....

[floobydust]

I drew a partial schematic of the BM2257 front-end and also agree, the (bigger) PTC2 get's grounded in LowZ mode (at S0B1) - not like some other BM235? I think that left the clamps in series which is what I was on about for the input impedance being two levels.

The only other DMM I know about with a deadzone is the AN8008 around +/-4uV it truncates to 0V to mask A/D noise.
I think here, for the BM2257 it might be for the superstitious multimeter users that freak out when it doesn't read zero?

Something else I noticed is some sloppy PCB layout again on the rotary switch rings. It's like the layout guy has 1 hour to pound this out lol.
The change to using four MOV's is also to save space.

[EEVblog]

I drew a partial schematic of the BM2257 front-end and also agree, the (bigger) PTC2 get's grounded in LowZ mode (at S0B1) - not like some other BM235? I think that left the clamps in series which is what I was on about for the input impedance being two levels.

Yes, the BM235 goes into a transistor zener clamp, hence will only conduct the PTC once it hits 7V or so. Interestingly, the BM235 does actually go lower than the BM2257 in LowZ, down to 0.5V

Something else I noticed is some sloppy PCB layout again on the rotary switch rings. It's like the layout guy has 1 hour to pound this out lol.

Yes, looks rushed! Didn't bother to reshuffle things when they they ran out of space, so added a bodge wire around the socket, a 10A jumper cable on the top, and a battery wire on the bottom.

[EEVblog]

My reverse engineered partial schematic, could have errors, stuff missing, but shows how it works.



Video to be released in the next few days:

[Kleinstein]

In normal operation there are 3 MOVs in series at the input. In low Z mode there are only 2 MOVs in series (VAR1+VAR2). So one may have a slightly earlier clamping, lower maximum voltage in low Z mode.

The loading part in low Z mode is just the resistor and PTC (looks like the same as for the ohm mode). There should be no good reason for a lower voltage limit in the low Z mode. There is just the point that the AC detection has a lower limit to detect AC.

[EEVblog]

In normal operation there are 3 MOVs in series at the input. In low Z mode there are only 2 MOVs in series (VAR1+VAR2). So one may have a slightly earlier clamping, lower maximum voltage in low Z mode.

It's still 1240V, above the max rating of the meter.

[bdunham7]

In normal operation there are 3 MOVs in series at the input. In low Z mode there are only 2 MOVs in series (VAR1+VAR2). So one may have a slightly earlier clamping, lower maximum voltage in low Z mode.

The loading part in low Z mode is just the resistor and PTC (looks like the same as for the ohm mode). There should be no good reason for a lower voltage limit in the low Z mode. There is just the point that the AC detection has a lower limit to detect AC.

Those MOVs are rated for 385VAC continuous, the lower "extra" MOV is 350VAC.  IDK for sure why they've added that lower MOV, but if the reason was to reduce leakage and keep the input resistance at 10M even at the maximum input voltage then that need would not apply to the Low-Z mode.   Another possibility is that the 4-MOV setup is a leftover design feature from a previous version that had the now prohibited 'CAT II/1000V' rating and now at CAT III/600V they don't need it but didn't bother to take it out. 

[floobydust]

Quite high voltage MOV's are not available in the small 5mm size. Fluke went with their custom Epcos S05K575 (575VRMS) 910V@1mA.
I see Brymen simply used two in series to get the same net clamping voltage in 5mm size, using off the shelf parts.
(625VRMS) 1,000V@1mA is a 10mm part, one used in predecessors BM235, BM786 etc. with a smaller 7mm in series.

You want the smallest size part for cost, low capacitance but big enough to pass the 61010 transient test which is a few amp spike.
Leakage current looks high I'm not sure if anyone has actually measured it at max. input voltage say 1,000VDC or 600VAC to see if is an unknown issue.
Clamping voltage I estimate is max. ~3,000V total in a few amp transient. joeqsmith has the data.

[bdunham7]

Leakage current looks high I'm not sure if anyone has actually measured it at max. input voltage say 1,000VDC or 600VAC to see if is an unknown issue.

With three in a row at 600V, that's 200V apiece and extrapolation puts that leakage current at a fraction of a µA.  At 600V a 10M input would have 60µA already, so not an issue.  With only two, the leakage current would be higher but in Low-Z mode your input impedance is probably less than 1M @ 600V and your current is >600µA and not very stable or certain anyway. 

[Furna]

[...] joeqsmith has the data.

While reading the last few posts, I thought it is time someone send a BM2257 to joeqsmith.
After Dave's video, we can get one more interesting video.

[EEVblog]

Quite high voltage MOV's are not available in the small 5mm size. Fluke went with their custom Epcos S05K575 (575VRMS) 910V@1mA.
I see Brymen simply used two in series to get the same net clamping voltage in 5mm size, using off the shelf parts.
(625VRMS) 1,000V@1mA is a 10mm part, one used in predecessors BM235, BM786 etc. with a smaller 7mm in series.

You want the smallest size part for cost, low capacitance but big enough to pass the 61010 transient test which is a few amp spike.
Leakage current looks high I'm not sure if anyone has actually measured it at max. input voltage say 1,000VDC or 600VAC to see if is an unknown issue.
Clamping voltage I estimate is max. ~3,000V total in a few amp transient. joeqsmith has the data.

I forgot the datasheet link:
https://www.cnr.com.tw/cloudSpace/CNR_D.pdf

Will test the leakage @1000V

[tautech]

[...] joeqsmith has the data.

While reading the last few posts, I thought it is time someone send a BM2257 to joeqsmith.
After Dave's video, we can get one more interesting video.

Not just yet.....there might be a revision like there was with the GW.......

[EEVblog]

Tested.
TLDR; Not a problem at 1200V DC and 1100V AC

[Furna]

Tested.
TLDR; Not a problem at 100V DC and 1100V AC

Watch the typo ... 1000V DC

[bdunham7]

Whoa...wait!  It has an undocumented 6000V range?   

[EEVblog]

Whoa...wait!  It has an undocumented 6000V range?   

In theory yes, try it   

[geralds]

[/quote]
Not just yet.....there might be a revision like there was with the GW.......
[/quote]

Would that be a FW update? If so, is it now possible to update the FW oneself (i.e. without sending it in for service)? I understand this was (generally) not possible with other Brymens?

Also (and again, apologies for such a Newbie query - I am a complete beginner and trying to learn...): How relevant is the LoZ "issue" for LV/electronics? In practice, would you use LoZ mode for electronics / hifi repair works?

Thanks!

[EEVblog]

Would that be a FW update? If so, is it now possible to update the FW oneself (i.e. without sending it in for service)? I understand this was (generally) not possible with other Brymens?

Only the BM780 series is designed for firmware updating. But even then the user can't do it, only a Brymen dealer who has access to the programming tool.

Also (and again, apologies for such a Newbie query - I am a complete beginner and trying to learn...): How relevant is the LoZ "issue" for LV/electronics? In practice, would you use LoZ mode for electronics / hifi repair works?

It's mainly for mains ghost voltage elimination, but there are niche uses for lower voltage work. For repair it's useful for safely discharging capacitors. But I have a video on that:

[Kleinstein]

The current specs for the MOVs are maximum values. As typical for leakage currents the actual value is often much better than the specs.
For those 200 Mohms range effective resistance already surface contaminations could be an issue.

The slightly higher current in the AC test can come from parallel capactance. The input impedance is not just the 10 M ohms, but also has a few pF of parallel capacitance inside the meter and also the cables outside. So I don't think it is leakage at the MOVs, more like the capacitance of the MOVs.

[dkarst]

I've been following this thread and don't think I've seen anything mentioned on the BM789.  It has been on the market with Low-Z capability (one if its key differences from EEVblog BM786).  I believe the spec for it is Low Z functionality with input < 1 volt.  I don't know if anyone here has looked at the input circuit topology.   Possibly, since the new BM2257 has this behavior at 0.9X volts, Brymen noted the behavior and made the spec <1V.  Maybe for the BM2257 they wanted to have a bit more headroom from spec and changed it to 1.5V.  It may also have a totally different input.

I guess just speculating since I don't have a BM789.  Just hadn't seen it discussed and thought interesting.   

[EEVblog]

I've been following this thread and don't think I've seen anything mentioned on the BM789.  It has been on the market with Low-Z capability (one if its key differences from EEVblog BM786).  I believe the spec for it is Low Z functionality with input < 1 volt.  I don't know if anyone here has looked at the input circuit topology.   Possibly, since the new BM2257 has this behavior at 0.9X volts, Brymen noted the behavior and made the spec <1V.  Maybe for the BM2257 they wanted to have a bit more headroom from spec and changed it to 1.5V.  It may also have a totally different input.

Welcome to the forum. I'd bet it's the same arrangement as the BM2257.

[J-R]

My BM789 bottoms out at exactly +/- 0.9000V DC in Auto V/LoZ mode.

[5U4GB]

It's mainly for mains ghost voltage elimination, but there are niche uses for lower voltage work.

I was recently doing some alarm re-wiring and there were ghost voltages everywhere, I wanted to use an NCV to check which sensor was wired to which input and it was impossible, almost every sensor registered a voltage present when disconnected.  As did the mains input to the alarm even though it was disconnected at the switchboard.

Really tempted to get a BM2257 now, I'd always considered Low-Z a bit of an extravagance (given the cost of the meters it came with), but after the recent episode...

[floobydust]

LowZ is a must have. Digital multimeters are too sensitive out in the real world - you'll get ghost readings due to capacitive AC coupling of mains, as well as DC leakage currents due to moisture and corrosion. Unless you have an analog VOM lol. 10MEG input impedance or higher leads to goose chases, I've been burned a few times troubleshooting.

[xKertx]

Does it have an option in it's settings that let's you choose whether you use normal alkaline batteries or Ni-Mh rechargeable ones?
Some quality meters have it (my Keysight multimeter and Vaisala thermo-hygrometer both have it) and i think it's a really nice feature. The low battery warning would be more accurate and you will not overdischarge/destroy your rechargeables.

[Furna]

Does it have a option in its settings whether you use normal alkaline batteries or Ni-Mh rechargeable ones?
Some quality meters have it and i think it's a really nice feature. The low battery warning would be more accurate and you will not overdischarge/destroy your rechargeables.

Short answer: no, there is no such setting.

Anyway in the general specifications at pag. 17 of the manual you can find the "Low Battery" voltage below approx 2.5V (so 1.25V each cell).
AFAIK lowest safe voltage for Ni-Mh is 0.9V.
IMHO perfectly safe to use Ni-Mh but (very) short duration since max for Ni-Mh is 1.42V and nominal 1.2V.

[Kleinstein]

Showing low Bat at 1.25 V is a bit on the high side for NiMH or NiCd. That is arealy above the 1.2 V nominal voltage.

The problem is not the maximum voltage - that can be at some 1.6-1.7 V, similar to very new alkaline cells.
The point is that the meter could show low battery when NiMH is still 95% full.

[xKertx]

Well the nominal voltage of the Ni-Mh is 1,2V when there is about 60% charge left. So that 1,25v threshold means you get the low battery warning all the time and eventually ignore it and have to guess when the batteries need to be charged.
It's little dissapointing because other than that it seem like a really nice DMM. I like to use ni-mh in my better equipment to avoid leakeage problems. 
I wish Dave could give them a hint and maybe they could add it to future firmware versions.

[Furna]

I guess there is also a cut-off min voltage ... so it is not that you get the low battery and ignore it ... the meter will shutdown.
What is the cutoff voltage? I have no idea.

[bdunham7]

Showing low Bat at 1.25 V is a bit on the high side for NiMH or NiCd. That is arealy above the 1.2 V nominal voltage.

The problem is not the maximum voltage - that can be at some 1.6-1.7 V, similar to very new alkaline cells.
The point is that the meter could show low battery when NiMH is still 95% full.

That depends on load.  The open-circuit voltage for a NiMH battery is almost always above 1.2 and usually even 1.25V after use at light loads.  Even at 50mA load on an AA cell, a 1.25V cutoff would yield more than 2/3 of the total capacity of the battery.  Most reasonable handheld multimeters will have a battery load much less than 50mA.  The ones that use 9V batteries can be below 1mA.

https://citeseerx.ist.psu.edu/document?repid=rep1&type=pdf&doi=5edecfd325c3787e2dd76a7460005bf5abe1758f

[Furna]

Test leads shorted and selector on Continuity/Beepr
still working at 1.77V (drowing 25mA)
shutdown at 1.76V
so 0.88 each cell
I would say safer for Ni-Mh ...
Anyway there must be a reason why Brymen choose 2.25V for low batt ... usually to guarantee reliable results.

Measurement done with a PSU

[Fungus]

Anybody got any Batterizers? 

[mwb1100]

NiMH has a flatter voltage/discharge curve than alkaline, so the low battery behavior might be OK.

Has anyone experience with using NiMH in the BM257s which is specified to show low battery when below 2.3V (no surprise that it's basically the same as the BM2257)?

[xKertx]

NiMH has a flatter voltage/discharge curve than alkaline, so the low battery behavior might be OK.

Has anyone experience with using NiMH in the BM257s which is specified to show low battery when below 2.3V (no surprise that it's basically the same as the BM2257)?

Yes, at low discharge currents the NiMh voltage is 1,2V most of the time, until it is almost depleted and the voltage drops.
The 2,5V threshold for the low battery warning is too high because the batteries will be half of the time below that.
2,3v (like on the bm257) would be much better because it would be below the NiMh's nominal voltage.

[mwb1100]

Yes, NiMh will be 1,2V most of the time until it is almost depleted and the voltage drops.
That's why the 2,5V is too high.
2,3v would be better

Yes - I got lost about what the low battery threshold for BM2257 is...  too many numbers between 1.2 and 2.5V being thrown around here for my feeble mind to keep track.

[5U4GB]

An alternative you can use, at the cost of slightly shorter times between recharges, is LiFePO4 batteries instead of NiMH.  This requires battery compartments which use cells in multiples of 2, since you're putting a LiFePO4 in series with an empty head (battery spacer that doesn't do anything), with the total having a combined voltage of the LiFePO4's 3.2V, equivalent to two fresh nominal-1.5V cells.

The other slight problem is that most standard chargers won't charge them, you'd need something like an MC3000 and even then it's not one of the standard charge programs.

[EEVblog]

FYI I split out the BM235 display lag/pause issue here:
https://www.eevblog.com/forum/testgear/brymen-bm235-multimeter-display-lagpause/

[eematt]

What does it look like without the backlight on?  Just a white LCD?
Are they able to offer it with the paper-white backlight or just the amber?

Same transflective sceen as the BM235. BM235 is slightly better at higher angles.
Haven't asked about backlight.

Hi Dave, thank you for sponsoring this meter as it checks a lot of boxes in a great form factor!

Regarding the backlight color, I personally view the orange backlight as jarring and almost cringey with the EEV blue and remaining monochromatic hue of the meter with the black body, gray buttons, and white silkscreening.  I appreciate that: everyone has their own personal perspective, the orange might offer better contrast, and that white LEDs need more voltage to drive than orange.  However, I suspect the majority of potential buyers would prefer a white backlight as it tends to present cleaner and more modern than legacy colors, the potential extra amount of contrast is insignificant, and driving a white backlight is possible with two AAAs as it’s EEV predecessor ( BM235 ) does exactly that.

I am curious to know if you are planning on keeping the orange backlight?  Or are you open to the idea of investigating a white backlight, or have existing plans to change the backlight color?

For the potential future EEV store multimeter model lineup, I recommend not offering both the BM235 and BM2257. The BM2257 is essentially just a better BM235 minus some insignificant details not relevant the target buyer pool.  And, the price point is only marginally more making it the clear choice regardless of budget allowance.

Thanks, long time viewer ( ~14 years ), first time poster.
Matt

[EEVblog]

Welcome.

Regarding the backlight color, I personally view the orange backlight as jarring and almost cringey with the EEV blue and remaining monochromatic hue of the meter with the black body, gray buttons, and white silkscreening.  I appreciate that: everyone has their own personal perspective, the orange might offer better contrast, and that white LEDs need more voltage to drive than orange.  However, I suspect the majority of potential buyers would prefer a white backlight as it tends to present cleaner and more modern than legacy colors, the potential extra amount of contrast is insignificant, and driving a white backlight is possible with two AAAs as it’s EEV predecessor ( BM235 ) does exactly that.

You are the only one who has complained about it that I know of.

I am curious to know if you are planning on keeping the orange backlight? 

Yes.

Or are you open to the idea of investigating a white backlight, or have existing plans to change the backlight color?

No, I like the orange.

For the potential future EEV store multimeter model lineup, I recommend not offering both the BM235 and BM2257. The BM2257 is essentially just a better BM235 minus some insignificant details not relevant the target buyer pool.  And, the price point is only marginally more making it the clear choice regardless of budget allowance.

If people keep buying it I'll keep selling it.

[J-R]

I mentioned on page 1 of this thread that I also prefer white or the blue-tinted white along with the EEVblog blue color, as well as that the BM2257 is based on the BM257, and the BM2251 the BM251.  So not the BM235.  They've also released the BM2800CSE series (CAT and shielded enhanced), which appears to be an updated version of the BM800s line.

Who knows why Brymen selects one color over the other.  The BM805s & BM806s have white, while the BM807s is orange, and the BM2800CSE series are all orange.

Furthermore, the BM251 has a white backlight while the BM2251 has orange.  Perhaps orange is the new white.

There were some Brymen-red BM2257 units available a while back, but I haven't seen any lately other than from Telonic, but they don't ship to the US.

[bdunham7]

If people keep buying it I'll keep selling it.

That is Fluke's entire marketing plan!

[EEVblog]

If people keep buying it I'll keep selling it.

That is Fluke's entire marketing plan!

It works.

[EEVblog]

Furthermore, the BM251 has a white backlight while the BM2251 has orange.  Perhaps orange is the new white.

That would be my guess, they prefer orange for new models for some reason.
Companies change colour all the time, like the recent black trend from the big test equipment makers.
There is a new model Brymen that I'll be carrying soon, I don't know what colour it has yet, will be interesting to see.

[rsjsouza]

I have a Greenlee DM-200A (BM251 equivalent) and its orange color suits well its display.

Since everyone has opinions, I personally prefer the orange to white - to me it is easier on the eye, but perhaps my opinion might be skewed by the plethora of white backlights on the cheaper models these days. Perhaps that is why Brymen is moving away from pure white - distance from the flooded market.

[TomKatt]

I'm too lazy to look - does this new meter have the flashing continuity?

I've got a Greenlee DM820A (rebranded BM869s?) that is a fantastic meter, but I much prefer the continuity on Dave's BM235...  It's just so easy to see the display in a loud production floor environment.

Also, I do prefer orange to white.  I'm not a fan of blue led's no matter what temp you call them.

EDIT - got off my butt and looked lol.  Yup, has 'BeepLit' technology lol.  Looks like a nice meter. 

[mwb1100]

White, orange, whatever.  I just want the backlight to last more than 30 seconds.  2 minutes is good, more is better.

There is a new model Brymen that I'll be carrying soon

Oh no!  I'm trying to cut back!

I don't know what colour it has yet, will be interesting to see.

If it's not blue, eevblog will explode!

[TomKatt]

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There is a new model Brymen that I'll be carrying soon

Oh no!  I'm trying to cut back!

LOL - I Googled BM2257 and the 2nd result is the EEVblog forum discussion on the meter and the 3rd result is Dave's store listing for it...  I didn't realize he was selling these already.  I live under a rock - the temperature and humidity are constant year round 

Edit - moved to 1st and 2nd place,... Google must be user specific?  Damn privacy invading cookies!

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[AVGresponding]

I have a Greenlee DM-200A (BM251 equivalent) and its orange color suits well its display.

Since everyone has opinions, I personally prefer the orange to white - to me it is easier on the eye, but perhaps my opinion might be skewed by the plethora of white backlights on the cheaper models these days. Perhaps that is why Brymen is moving away from pure white - distance from the flooded market.

Either that, or copying Keyshite

[Sebekh]

Dave can you tell me more about the new brymen multimeters. I wish they would add the 2257 features to my favorite bm857s. The 86x 82x 83x series is too big for me

[TomKatt]

The data sheet and manual are posted on the bottom of Dave’s store page…

https://eevblog.store/products/eevblog-bm2257-multimeter?srsltid=AfmBOooVrrpdOzbQPKy9aR6gUWLshmoVVCP7ufXZ2pk77JaGvTKEpg3W

[EEVblog]

Dave can you tell me more about the new brymen multimeters.

I'm not sure if they want me to say anything, but it's been something long promised.

[Sebekh]

Dave, can you at least tell us when we can expect some news?