EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: jysd on March 20, 2019, 11:52:08 am
-
Hi all,
I just bought a Brymen BM867s (after intially planing on buying a BM869s), received it a couple of days ago and started testing.
First thing I noticed was the uneven backlight, there's some "black clouds" on the left part of the display. Then I went on to test
DC voltage from PSU and saw some terrible ghosting on the display. Surely this can't be acceptable?? (see attached photos).
Does your bm867s/bm869s look like this?
Thanks,
Jonny
-
Hi,
our companies 867 display is sharp and clear.
No signs of shadows/ghosting.
Maybe the conductive rubbers of the display or the display itself aren´t properly fixed?
I´d return the item and ask for a replacement.
Will also check with my own 867 when I´m home from work.
regards
Calvin
-
My Bryman 867s is clear no sign of ghosting.
My Backlight is the same as yours but no ghosting.
-
Hard to say really. I would imagine if I took any meter with a varying signal, set the camera exposure right, I could get all sorts of ghosting as shown. I would imagine I could also drop the temperature enough to get some pretty good ghosting on most meters.
I recently looked at a Yokogawa meter that has the contrast cranked up pretty high which causes deselected segments to show up.
Here you can see a few Fluke meters along with one of my BM869s outside in the sun from various angles.
https://youtu.be/DA77DYGE6IM?t=654
-
Hard to say really. I would imagine if I took any meter with a varying signal, set the camera exposure right, I could get all sorts of ghosting as shown. I would imagine I could also drop the temperature enough to get some pretty good ghosting on most meters.
I recently looked at a Yokogawa meter that has the contrast cranked up pretty high which causes deselected segments to show up.
Here you can see a few Fluke meters along with one of my BM869s outside in the sun from various angles.
https://youtu.be/DA77DYGE6IM?t=654
It's in 20 degrees Celsius ambient temperature. The ghosting is almost looking worse IRL than on the pictures. I haven't tried to maximize the ghosting issues in the pictures either, it's just plain and quick mobile photos.
I can take more photos if you'd like from other angles and in different lighting scenarios. From a real world perspective it's really difficult to read out the display, it would take me several seconds to read one measurement
properly. I could live with the uneven backlight, but not the ghosting.( I mean the regular use case is to quickly glance at the DMM to get a reading, but in this case that's not possible, it's that bad IMO)
-
Mine only shows very slight ghosting when looking from really low angle, doesn't affect reading it and shows in all segments, not just some. (Afaik, that low-angle effect is typical to these type of LCDs, and not really 'ghosting'.) Caveat, I didn't try measuring real voltages, just my body static with mV range.
So, imho, OP's ghosting is not normal. Especially the special segments (triangle, R, MAX) probably should not be showing up even if the photos would have been taken with too slow shutter speed.
-
What's your room temperature?
Contrast varies with temperature
-
What's your room temperature?
Contrast varies with temperature
It was around 20 degrees Celsius. I've tested it at work where it's 20-22degrees C as well, same result.
Mine only shows very slight ghosting when looking from really low angle, doesn't affect reading it and shows in all segments, not just some. (Afaik, that low-angle effect is typical to these type of LCDs, and not really 'ghosting'.) Caveat, I didn't try measuring real voltages, just my body static with mV range.
So, imho, OP's ghosting is not normal. Especially the special segments (triangle, R, MAX) probably should not be showing up even if the photos would have been taken with too slow shutter speed.
The shutter speed is not an issue here, it does look atleast as bad (IMO worse) IRL when looking at the meter.
I hooked it up to a DP832 PSU and just measured the voltage on one of the output terminals when I took those photos. My intention was to test 0-32V on the DP832 and see what the DMM
measured. Depending on which segments are lit on the DMM (varying with input voltage ofc), the ghosting appeared and disappeared. I'll attach another photo here from the same time I took the others,
at 11V the ghosting isn't visible (EDIT: Dunno why the forum decided to rotate the picture like that, it's taken just like the others :) )
-
Definitely not. Return it if you can.
-
I hooked it up to a DP832 PSU and just measured the voltage on one of the output terminals when I took those photos. My intention was to test 0-32V on the DP832 and see what the DMM
measured. Depending on which segments are lit on the DMM (varying with input voltage ofc), the ghosting appeared and disappeared. I'll attach another photo here from the same time I took the others,
at 11V the ghosting isn't visible (EDIT: Dunno why the forum decided to rotate the picture like that, it's taken just like the others :) )
Now that is getting interesting. I'd test this myself, but most of my stuff is currently neatly packed in the cabinet (curses of "lab" == living room). I wonder how it would look with, say, measuring two or three 9V batteries in series. I'm thinking about the possible noise on the power supply somehow coupling through and affecting the LCD or its driving circuitry; batteries should not have such noise.
I don't remember to ever have seen such ghosting, even when testing DPS5020 and DPH5005 from 0 to the max voltages, and the Meanwell PSUs feeding them (36V and 48V+).
-
Now that is getting interesting. I'd test this myself, but most of my stuff is currently neatly packed in the cabinet (curses of "lab" == living room). I wonder how it would look with, say, measuring two or three 9V batteries in series. I'm thinking about the possible noise on the power supply somehow coupling through and affecting the LCD or its driving circuitry; batteries should not have such noise.
I don't remember to ever have seen such ghosting, even when testing DPS5020 and DPH5005 from 0 to the max voltages, and the Meanwell PSUs feeding them (36V and 48V+).
Hehe, interesting thought (which if true would be kind of a big problem for a DMM?). Not the case though, just to be sure since the DP832 is new as well, I hooked it up to the scope (Siglent SDS1104X-E) and it showed < 10mV ripple while ghosting on the BM867s. I also noticed that the upper segment on the leading digit (3) had less contrast than the other segments, a lot less actually. I’m in contact with both the reseller and Brymen (Biall something?), awaiting their response.
Good to know that no one else (so far) has these issues, which suggests that the unit is indeed faulty.
-
Does your bm867s/bm869s look like this?
Here are a couple of pictures of my BM869s. I'd say yours might be faulty.
(https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/?action=dlattach;attach=454336;image)
(https://www.eevblog.com/forum/testgear/brymen-multimeters-fault/?action=dlattach;attach=273189;image)
-
If you look at a fairly shallow angle up at the screen, I get a similar look on my few-year-old BM867s, but certainly not right on and not with the backlight.
-
Hard to say really. I would imagine if I took any meter with a varying signal, set the camera exposure right, I could get all sorts of ghosting as shown. I would imagine I could also drop the temperature enough to get some pretty good ghosting on most meters.
I recently looked at a Yokogawa meter that has the contrast cranked up pretty high which causes deselected segments to show up.
Here you can see a few Fluke meters along with one of my BM869s outside in the sun from various angles.
https://youtu.be/DA77DYGE6IM?t=654
It's in 20 degrees Celsius ambient temperature. The ghosting is almost looking worse IRL than on the pictures. I haven't tried to maximize the ghosting issues in the pictures either, it's just plain and quick mobile photos.
I can take more photos if you'd like from other angles and in different lighting scenarios. From a real world perspective it's really difficult to read out the display, it would take me several seconds to read one measurement
properly. I could live with the uneven backlight, but not the ghosting.( I mean the regular use case is to quickly glance at the DMM to get a reading, but in this case that's not possible, it's that bad IMO)
Being brand new, I would just return it for a replacement.
-
I've seen that with some Fluke 175 as well. The contrast seems too high and I don't think there is any contrast adjustment. It could also be something wrong with the LCD driver or the bias voltages. I would return it.
-
I recently bought a new BM867s and the display is clear and crisp without any ghosting at all.
Like some others have suggested, if you can I would return it.
-
Hi guys,
Sorry for the update delay. I contacted both Brymen and the reseller, Brymen replied that the factory had been informed (it seems to have been a batch problem, my own guess) and offered to replace it.
The reseller gave me several options and I decided to ship it back for a swap, and then paid a couple of euros extra to get the BM869s instead :)
The new BM869s I received works flawlessly so far. The darker "clouds" are still there on the left part with backlight ON, although a little bit less noticable. However the terrible ghosting is nowhere to be found thankfully.
All in all, everything is well now. Thanks for your input! :-+
-
It appears that there is some connectivity issue with the Zebra strips in the display.
If you clean the strips using some IPA the ghosting issue is fixed!