Products > Test Equipment

Brymen BM789

<< < (43/50) > >>

EEVblog:

--- Quote from: sonpul on July 09, 2024, 03:56:27 pm ---Via bluetooth? Which was planned, but never appeared. It looks more like a sound symbol, a signal symbol.

--- End quote ---

Yes, bluetooth was planned and they promised it but it never happened  :(

YulyPH:
Had my brand new BM789 (from welectron with dakks calibration) for a week and I just want to share some info.
Firmware version is 13 so I guess they are still making improvements.
BM869s seems like a mistake as BM789 is better for AC voltage (more accurate voltage up to 100kHz - both meters go higher than that) and the readings are way faster (BM869s needs a few seconds to stabilize).
BM869s has the edge only in AC current but BM789 is not that far off, even if the datasheet lists only 3kHz it goes almost as high as BM869s.

I strongly recommend lubing the rotary switch as it's quite bad feeling out of the box. Super lube works perfectly.

Now for the those that like to compare backlight duration.
Every DMM that I owned switched the backlight throw a transistor so you could replace it with a resistor to limit the current and have the battery last longer with always on backlight.
Why do Brymen meters have backlights as bright as a flashlight ? If I want a flashlight I don't use a DMM  :palm:.
The BM789 is a bit special as the backlight is connected directly to the battery so it's not going throw the rotary switch.
The only way to have always on backlight is to get a voltage to the base of the transistor that is switched from the rotary switch (luckily there is a 3.5V track next to the transistor base track).
The mod can be done without removing the screen (just the plastic that holds the screen and backlight board then remove the backlight board with care) and is doable on the front or the back of the meter (I recommend cutting the transistor base trace and attach it to the 3.5V rail).
Anyway, around 60mA with default 150R resistors (R57, R58 and R84) and 17mA with 500R resistors (the result is more than enough backlight).
Even with good environment lighting the backlight makes the screen more readable.
Maybe one day Brymen will copy Uni-t :box: (UT622 LCR meter with color screen and backlight adjustable from keys is just perfect or maybe UNI-T UT181 but I don't own one to be sure the screen is good).

joeqsmith:

--- Quote from: YulyPH on August 05, 2024, 06:25:10 pm ---...BM869s seems like a mistake as BM789 is better for AC voltage (more accurate voltage up to 100kHz - both meters go higher than that) ...

--- End quote ---

BM869s supports logging, dual display, and while a few claim the 500k count is a gimmick, I have used it to hunt problems. 

I suggest buying the tools that fit your personal needs.  The only mistake is not doing your homework. 

YulyPH:

--- Quote from: joeqsmith on August 05, 2024, 07:50:16 pm ---BM869s supports logging, dual display, and while a few claim the 500k count is a gimmick, I have used it to hunt problems. 

I suggest buying the tools that fit your personal needs.  The only mistake is not doing your homework. 

--- End quote ---

Your right, and here we are talking about portable DMM's that are general purpose meters.
The 500k count is considered a gimmick because it's useless without measurement precision and stability.
The BM789 has the extra digit for frequency in contrast to BM869s extra digit for DC voltage.
BM869s and BM789 are above budget toy meters but at the same time they are not lab grade (maybe entry level).
As long as you don't need data logging the BM789 seems the better one as a general purpose meter.
And this was the answer that I was searching for that no one seemed to give.
Even ChatGPT says that BM869s has better accuracy with more features and the BM789 is the budget option  :-DD
Both calibrated and purchased a week apart from each other on DC they agree and for AC voltage the BM789 is way better.
Had to get them both to reach this conclusion.

joeqsmith:

--- Quote from: YulyPH on August 05, 2024, 10:07:26 pm ---...
The 500k count is considered a gimmick because it's useless without measurement precision and stability.
...

--- End quote ---

I was once told there was never a reason to measure anything beyond 60Hz.   In many cases, I am looking for a relative change only.  Obviously your use case is different.  Not to suggest your statement is wrong but that we all have different requirements.

Navigation

[0] Message Index

[#] Next page

[*] Previous page

There was an error while thanking
Thanking...
Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod