EEVblog Brymen BM235 - LCD issues or normal?

[joeqsmith]

Not sure why you would start a thread about the BM235's LCD then turn to how great the 61E is in comparison.   Just trolling?   No matter.  While there was a fair amount posted about adding MOVs to the 61E for one reason or another,  I will say that the 61's I looked at failed with a small ESD hit.   The Brymen I have does calls out the 61326 EMC standard, which covers ESD and of course the meter has no problem with it.   Not to say the BM235 would not. 

The constant gripe you hear for the UT61E is the lack of input protection which is true, but how many
times will the electronics hobbyist start probing CAT IV installations ?...

[hgg]

Not sure why you would start a thread about the BM235's LCD then turn to how great the 61E is in comparison.

Very simple.  When I received it I really thought that I've got a faulty unit.

If it was trolling do you think I would spend 100 euros to buy the BM235? 

Its just plain fact.  The UT61E is an very nice multimeter especially for the price range and better
than the BM235 in some areas. 

For one, if I knew that I will get such a low quality LCD, the BM235 would have been out of the question
no matter how many kV it can withstand...

[kenabi]

the only angle my 235 lcd will fade out when tilted is when i'm looking at it from an overhead-ish angle, and even then it's readable. half there, but i can still tell what it says.

about the same as most of my other meters, including an old fluke from the early 90s.

/shrug

[hgg]

Now, is this a bug or just a quirk ?   

When you take voltage measurements, 1 out of 10 times instead of locking on the correct value,
it locks on a smaller value a few counts out and then starts ramping up slowly.  BM869s does not
do that.

https://youtu.be/KYinhq59tWI

[PA0PBZ]

A common complaint.
The viewing angle seem to be dependent upon the angle to the light source.
Here are two examples, one taken flat on my bench with light below the LCD, and angle taken from above the LCD. Looks fine.
The other taken from the same angle, but with the meter vertical and the light source now above the LCD. Badly faded out.

Guess where 99% of the light sources are in respect to the LCD... 

[EEVblog]

A common complaint.
The viewing angle seem to be dependent upon the angle to the light source.
Here are two examples, one taken flat on my bench with light below the LCD, and angle taken from above the LCD. Looks fine.
The other taken from the same angle, but with the meter vertical and the light source now above the LCD. Badly faded out.

Guess where 99% of the light sources are in respect to the LCD... 

Many benches (including mine) are up against a wall, and the ceiling lights are worst case either directly above, or back a panel or two on the roof. So in a typical office environment like mine, the light will most likely come from above or below the LCD when it's lying flat.
My photo above BTW had the light almost 90deg above the LCD, the meter was held completely vertical under the light.

[joeqsmith]

Did you ask about returning it?   

Not sure why you would start a thread about the BM235's LCD then turn to how great the 61E is in comparison.

Very simple.  When I received it I really thought that I've got a faulty unit.

If it was trolling do you think I would spend 100 euros to buy the BM235? 

Its just plain fact.  The UT61E is an very nice multimeter especially for the price range and better
than the BM235 in some areas. 

For one, if I knew that I will get such a low quality LCD, the BM235 would have been out of the question
no matter how many kV it can withstand...

[PA0PBZ]

Many benches (including mine) are up against a wall, and the ceiling lights are worst case either directly above, or back a panel or two on the roof. So in a typical office environment like mine, the light will most likely come from above or below the LCD when it's lying flat.

Yes, I see what you mean and I can confirm that when lit from more or less below the LCD looks better. Unfortunately I like my meter somewhat on the back of the bench and when it lies flat there it is very hard to read, I guess because my bench is a bit higher than a normal table. When I put it upright the display starts fading whenever you view it upwards from a right angle, something none of my other meters show. Maybe I should just post some pictures.

[Jayeson]

My experience with my BM235's display is consistent with the OP's pics. Since posting earlier (sorry, different, wrong thread), I noticed that the display has a curved window over it. IMO, this is a mistake in form over function - it tends to pick up reflections from everything.

There is a bit more going on than just lighting angle. Outside today in direct sun on a perfectly clear day, with care to avoid any reflections (very hard with this meter - I would never get this for outside work), I get good contrast looking almost directly on, and at all angles to the sun. I can't look directly on as all I can see is my own face. In a dark room with the meter's backlight, I get the same poor contrast shown in the OP's example pic.

With the meter lying flat on my bench, backlight off, and me standing, the view angle is low and I also get low reflections. In this situation the display is readable, although somewhat dark. I like to sit, and in that situation with the meter propped up on its stand (looking straight on at the meter's display), the reflections and low contrast make the meter unusable without the backlight. I was not able to find a lighting setup that worked. And with the backlight on, it is hardly great.

I see at least one person saying that their BM235 display is on par with their other meters. There is something very different in our situations. I've never had a usability concern of this level with *any* digital display on any device, although the very early TFT laptop LCD's would be taking second place. That experience includes a number of meters, from a c1989 cheapie, to a more recent (although still old) Fluke. Those, they just work.

This is all quite frustrating since the compact size and the rest of the features make for a great all-round meter. At AU$135, Dave has made available what was almost, for me in Australia, the best deal by a mile. But like the OP, I don't really understand how the meters got released this way. Or the noisy backlight for that matter. And certainly, why these issues wouldn't be decisively fixed ASAP.

[Hydrawerk]

My experience with my BM235's display is consistent with the OP's pics. Since posting earlier (sorry, different, wrong thread), I noticed that the display has a curved window over it.

A curved window is more durable.

[Fungus]

For 500USD, the Keysight U1282A might have a better LCD.

My $4 'Harbor Freight' seems to have a better LCD.

[EEVblog]

I asked Brymen and their response is:

To change R67 (currently 12.7k) to 17.8k or further to 21.5k may improve LCD contrast drastically. Please try.
 By the way, such way will increase LCD bias voltage to have LCD with better contrast. However, it has a negative affection. It may introduce some ghost segment display from some angle view. That was the reason why our production did not use 17.8k or 21.5k for R67. 

Sounds like a simple contrast issue rather than LCD production issue.
I might try this tomorrow.
Feel free to try yourself and report.

[iXod]

The constant gripe you hear for the UT61E is the lack of input protection which is true, but how many
times will the electronics hobbyist start probing CAT IV installations ?...

Who says that bench-bound techs are the only buyers of UT61's? Many might be field techs...

[Kilrah]

I received mine yesterday and looks same, it very much seemed like contrast set too low and I was going to look at how to change that so it's good to have confirmation and a significant shortcut... will have a look.

[iXod]

Sounds like a simple contrast issue rather than LCD production issue.
I might try this tomorrow.
Feel free to try yourself and report.

Are components ("R67") labeled on the pcb? (No, I did not "Don't turn it on, take it apart!!!") lol

iX

[Kilrah]

You apparently didn't RTFM either 

[iXod]

You apparently didn't RTFM either 

Ha! I did but not all the way through. Leave it to Dave to provide hires photos--you can almost read the value designations!

I'll try this mod this weekend...

iX

[EEVblog]

[System Error Message]

EEVBlog is now a brand :O ?
How long before there will be EEVBlog oscilloscopes and slippers? Perhaps Dave could start merchandising.

[hgg]

Thanks Dave, great video and explanation.  BM235 is way better now!  Such a simple fix, they should have done it from the start.  What happened to foundamental Fridays?  We need more!  :-)

[Kilrah]

Done, I seem to be pretty happy with 35k.

Thanks for the explanations about LCD technology , but... it's nothing new, rather the opposite since back in the days they would often have much tighter vewing angles than we can have now.

The big difference is that "in the good old days" if manufacturers couldn't use an LCD with a high enough viewing angle or temperature stability for it tolook good enough in all normal usage conditions they would add a contrast setting for the user to be able to adjust to their preference and the temperature conditions, pretty much every device (even new) that I have and has a B/W LCD has a contrast adjustment. The first thing I tried was actually to power up the meter while holding a button to see if there was an undocumented software-controlled contrast adjustment as that would have been the most sensible thing to do IMO.

One thing that is weird with this LCD (or the way of driving it) and that' I've never seen before is that not all segments have the same contrast. I'd vote for the way of driving being the cause as it depends a bit on display contents.

[Fungus]

The big difference is that "in the good old days" if manufacturers couldn't use an LCD with a high enough viewing angle or temperature stability for it tolook good enough in all normal usage conditions they would add a contrast setting for the user to be able to adjust to their preference and the temperature conditions, pretty much every device (even new) that I have and has a B/W LCD has a contrast adjustment.

This.

Everything used to have a contrast adjustment. Modern tech has taken a step backwards here.

eg. Look at the difference with backlight on/off. If it had a contrast adjustment you could use it with the backlight on.

[Wirehead]

EEVBlog is now a brand :O ?
How long before there will be EEVBlog oscilloscopes and slippers? Perhaps Dave could start merchandising.

Flux Capacitor Slippers, I'd buy them immediately 

[Kilrah]

BTW to clarify I'm not complaining but just observing especially since I've been through just that, people are very picky about the screen on devices where it's a component that's fundamental to operation.
I've worked on a product that came out 3 years ago with a B/W dot matrix LCD that was "okay" but not great, there was some banding that would darken the light areas of columns that had a lot of dark pixels and that would change a bit with contrast. All the samples of the product we had seemed to respond pretty similarly so to avoid a bit of work we hardcoded contrast to something that we thought was the best compromise. Thankfully contrast was software-controllable on that display module, because when the product came out the customer response about that was so big that the first firmware update had the only purpose of adding a contrast adjustment.
The product's manufacturer then worked with the LCD manufacturer to come out with a better LCD design with no more banding problems and a wider viewing angle for the next hardware revision just because it became obvious that the display was a much more important point for a customer's satisfaction / impression of the product's quality than anticipated.

And that's all on a product that is comparatively much more "low cost" in its market than the BM235 is.

[Fungus]

BTW to clarify I'm not complaining but just observing especially since I've been through just that, people are very picky about the screen on devices where it's a component that's fundamental to operation.

It's not that they're being picky, it's because they own cheapo items that seem better than this $100+ item.

eg. I've got a $4 "Harbor Freight" here that doesn't seem to suffer this lighting problem*.

I'm with Dave: It's a design problem, they chose the wrong resistor.

So far he's found two badly chosen components in this meter. It doesn't say much for Brymen's design process.

(*Disclaimer:I don't own one of those EEVBLOG meters to put side by side, I'm just going by what I see in the video)