Brymen BM789

[Neutrion]

The treshold for continuity is between 100Ohm and 420Ohm.
What is it? I can't think it is just accidentally so high.

It might be that they use a low test current.  Unfortunately, continuity threshold is a spec that we will all never agree on, so the only solutions are to either live with what you get or find a meter that has selectable thresholds--which is pretty rare.

OK, but what is the case for high Ohm values?  I found many discussions where it was pointed out that some meters have a too high test voltage (like the Fluke 87V with 7 V.) which sometimes can damage things but not much discussion about where you could use such a high Ohm value for continuity?
I want to get now a(....searching for the term... ) "Choice-supportive bias or post-purchase rationalization" supportive oppinion.

I only could think about getting through dirty  contacts, or something like this. Now the meter is fast at continuity testing, so if I constantly read the display I can have an Idea that it is not a short, but than I could do it without the buzzer function as well.

[Fungus]

I found many discussions where it was pointed out that some meters have a too high test voltage (like the Fluke 87V with 7 V.)

All those discussions are wrong.

It's not a test voltage, it's a test current, use Ohms law to figure out the voltage.

In the case of the Fluke the maximum voltage is 7V. If Ohms law gives you a number higher than that in the previous step then it will be limited to 7V and the test current won't be reached

[Neutrion]

So these are the discussions I found on this topic to not to start it again:
https://www.eevblog.com/forum/testgear/multimeter-with-low-continuity-test-voltage/
https://www.eevblog.com/forum/eda/pcb-reverse-engineering/msg668285/#msg668285
https://www.eevblog.com/forum/testgear/what-do-you-think-of-the-new-fluke-87-v-max/275/

I know this is not an argument, but I am happier with a lower voltage.  But still no good use for the high Ohm range!?      

[vqtrong]

Hi, I just bought a new BM789.

All functions are good. It is better then my Fluke 116 in measuring ripple voltage, as BM789 has Peak Hold (Crest).

Just one thing I concern is it comes with version 06, which is not the latest version (08 atm).

Is there any big update in 08 version?
Is there any way to update to the latest firmware?

And there is an icon (((D))) showing up in LCD if I follow this sequence:
In AC mode --> Enable VFD --> Change to Hz mode --> Enable REC (Min, Max)

[Neutrion]

That's strange. Can you go back to normal mode without any issues? Do the values change just like if the meter would work normaly? Or what does it do?
I don't want to screw my meter by accidently entering into some calibration mode, though I have the FW version 08.
"D" could stand either for "Dave", or maybe "detonator"?  Does it counting back when you activate it?
Just checking whether you can log into the forum a second time...

It's also interesting that it also has the small lightning symbol like some other meter, but it never shows it. Some legal disputes with Fluke?

[Kean]

I don't know if the fixes for FW 08 have been posted anywhere, but earlier ones are listed in a post by Dave at https://www.eevblog.com/forum/testgear/new-eevblog-bm786-multimeter/msg3624885/#msg3624885

From what Dave has said, firmware updates can only be done by factory or possibly by the distributor.

Interesting icon you found.  Not seen that in any of the docs.  It could be a bug, or a hidden feature not intended for end users.  D for diagnostics?  D for data?

[vqtrong]

That's strange. Can you go back to normal mode without any issues? Do the values change just like if the meter would work normaly? Or what does it do?
I don't want to screw my meter by accidently entering into some calibration mode, though I have the FW version 08.
"D" could stand either for "Dave", or maybe "detonator"?  Does it counting back when you activate it?
Just checking whether you can log into the forum a second time...

It's also interesting that it also has the small lightning symbol like some other meter, but it never shows it. Some legal disputes with Fluke?

Hi, I'm here ^^ That icon only disappears when turning the dial. Luckily there is no tick-tock sound or any counting-down timer

I don't know if the fixes for FW 08 have been posted anywhere, but earlier ones are listed in a post by Dave at https://www.eevblog.com/forum/testgear/new-eevblog-bm786-multimeter/msg3624885/#msg3624885

From what Dave has said, firmware updates can only be done by factory or possibly by the distributor.

Interesting icon you found.  Not seen that in any of the docs.  It could be a bug, or a hidden feature not intended for end users.  D for diagnostics?  D for data?

I think it is for Data. I have not seen any Brymen DMM shows that icon when connected to PC. Is there any one having BM896s seeing this icon?

[vqtrong]

Searching around, I found a post from Cymaphore
https://www.eevblog.com/forum/testgear/new-eevblog-bm786-multimeter/msg3625880/#msg3625880
in which he said "Data port for BT is present under the display but unused in the standard BM789."

Have seen anyone hacked to that data port

[Fungus]

From what Dave has said, firmware updates can only be done by factory or possibly by the distributor.

Yep. Calling it "firmware" is a bit of a misnomer. It's more of a ROM.

Brymen sent joe a firmware "update" in the form of a new chip to be soldered in. The calibration was a bit off after he fitted it.

TLDR: Whatever "firmware" you got with the meter is what you get.

[Fungus]

Interesting icon you found.  Not seen that in any of the docs.

It looks like a some sort of wireless data transfer icon to me.

Does anybody with newer firmware get the icon with that button sequence?

[Kean]

Yep. Calling it "firmware" is a bit of a misnomer. It's more of a ROM.

Brymen sent joe a firmware "update" in the form of a new chip to be soldered in. The calibration was a bit off after he fitted it.

TLDR: Whatever "firmware" you got with the meter is what you get.

Nope, it is not ROM.
It can be updated, but only with the right equipment as provided by Brymen - so not by the end user. (at least not yet)

[Neutrion]

That's strange. Can you go back to normal mode without any issues? Do the values change just like if the meter would work normaly? Or what does it do?
I don't want to screw my meter by accidently entering into some calibration mode, though I have the FW version 08.
"D" could stand either for "Dave", or maybe "detonator"?  Does it counting back when you activate it?
Just checking whether you can log into the forum a second time...

It's also interesting that it also has the small lightning symbol like some other meter, but it never shows it. Some legal disputes with Fluke?

Hi, I'm here ^^ That icon only disappears when turning the dial. Luckily there is no tick-tock sound or any counting-down timer

I am glad that you survived. Brymens are generally safe meters I am sure it would tell us to take cover!

But I still did not dare to try it. What does the display show when the "d" appears? Can you normally measure voltage with it? All the other options are working?

Does anyone know what the processor(not the frontend) of the meter is? If we suppose its one of the Hycons, what could be the price difference to get something with decent memory? (Apart from the current crisis of course) The are plenty of MCU on the market I suppose.
Also interesting why the 789 needs the extra shielding and pots compared to the 786.

And one general question about multimeter backlights: The reason no pwm is used to not to screw the measurements? Because if all the manufacturer are worrying about the power consumption of the backlight, why not implementing a pwm some sort?

[AlexTee]

May I ask owners of this lovely DMM to test something for me before I order one for myself?
According to the user manual the continuity test should turn on audible sound if the circuit resistance is lower than 100 Om with response time of 100 μs.
Could you please confirm this statement? Probe a resistor of say 10-20 Om, and see if the buzzer comes on immediately. Because as I figured out recently, not all meters can do that, some turn on buzzer with significant delay if there's a small resistance present.

[Caliaxy]

According to the user manual the continuity test should turn on audible sound if the circuit resistance is lower than 100 Om with response time of 100 μs.
Could you please confirm this statement? Probe a resistor of say 10-20 Om, and see if the buzzer comes on immediately.

Yes, it beeps with no delay up to at least 120 Ohms.

[AlexTee]

Nice. Now, the question that still remains somewhat unclear to me is what's the idea behind setting such a high threshold of up to 420 ohm for continuity test. It means I need to throw a glance at the screen every single time I hear the beep, because it might happen to be just a resistor of 200 ohms along the tested path.

I re-read last pages, and found user Fungus explained that this is related to using a very small current in this mode. So, if I understand it right, the small amount of current is the root cause why the threshold is pushed high enough and enclosed in a range for the meter to detect sufficient voltage deviation over the tested path to distinguish between short/open condition. Sounds legit?

[HAO]

Hi everyone. I have BM869s and BM789. Both meters have not good battery life.

BM869s :
Power Supply: Single Alkaline 9V battery
Power Consumption: 6.5mA typical; 8mA for VFD ranges
Low Battery: Low Battery: Below approx. 7V

BM789
Power Supply: 1.5V AAA Alkaline battery x 3
Power Consumption: 10mA typical for AC & AC+DC Voltage/Current functions; 8mA
typical for other functions
Low Battery: Below approx. 3.7V

Do they work well with NiMH cells and not show low battery indicator?
AAA Eneloop for BM789
Energizer NH22-175 or Ansmann Akku 9V 300 mah for BM869s.

I also have Fluke 87V and Fluke 117. Should I stay with Energizer, Panasonic Alkaline or switch to rechargeable batteries ?

[joeqsmith]

Hi everyone. I have BM869s and BM789. Both meters have not good battery life.

So far, the best meter I have looked at for battery life was the free meters we get from HF and the Fluke 17B+.  I estimate both around 1200 hours.   Much better than the two meters you mention.  The worse I have seen was the UNI-T UT181A.  Maybe 40 hours between charges on a new battery, and the meter can't be used when it is charging which is done overnight.   

I have been using rechargeable Lithium-ion batteries with the BM869s.   The ones I have are marked 600mAh.  I've not had any problems using them. 

[EEVblog]

Searching around, I found a post from Cymaphore
https://www.eevblog.com/forum/testgear/new-eevblog-bm786-multimeter/msg3625880/#msg3625880
in which he said "Data port for BT is present under the display but unused in the standard BM789."

Have seen anyone hacked to that data port

Not possible because the firmware does not output and signal you can use.
I requested this way back in the development of the meter, saying it would be a popular user retro-fit, and Brymen agreed. But they couldn't get it done for some reason and the feature was not implemented.

[Antrus]

Greetings to all. I have a question about measuring resistance with this multimeter. At first it shows a slightly lower value, after a second the final one. Is it so for everyone? Firmware 78908.In reviews, he showed the value immediately.

[Grandchuck]

Sounds like capacitance is involved?

[Antrus]

Do you mean the capacitance is the internal capacitance of the multimeter? Since only the resistor is measured. This happens only in auto-range mode when measuring from several kilo-ohms.

[Grandchuck]

I meant capacitance in the circuit under test.  I have no other suggestions.

[supertrabuco]

Hello, the kings of the east have visited me and have left me an EEVBlog BM786.
Greetings and happy new year to all the electronic family ;

[Caliaxy]

Greetings to all. I have a question about measuring resistance with this multimeter. At first it shows a slightly lower value, after a second the final one. Is it so for everyone? Firmware 78908.In reviews, he showed the value immediately.

Mine does pretty much the same thing - it shows an intermediary value (pretty close to the final one) after about a second and a final stable value after about another second (tried to measure a 2k2 resistor in auto-range). I wouldn't worry too much about this, just be patient and keep in mind that the first value shown is not the final one.

Many low cost meters do exactly the same (also tried Uni-T UT61e). BM235 doesn't, it shows directly a final value and so does Fluke 87V (which also measures about 25% faster than BM789).

BM789 is a very accurate (and great for its price) meter, but not exactly a joy to use. Still a nice one.

[Antrus]

It would be better if he did not show this intermediate value. I am sure that the firmware can fix this.