EEVblog Electronics Community Forum

Products => Test Equipment => Topic started by: Sparky Faraday on February 12, 2020, 05:07:49 pm

Title: BM235 back light issue
Post by: Sparky Faraday on February 12, 2020, 05:07:49 pm
I just received my BM235 so I checked it out for issues and I found 1. The back light would sometimes not work and tapping the side of the meter would bring it back so I took it apart and found the springs that make the connection from the mother board to the LED board were not touching the LED board reliably.

I let Dave know about this. He said he had not heard of this issue from others. So I'm the chosen one |O!
I feel so lonely. If anyone else has had this problem please send a note to this thread and let Dave know

I told him I would post this to the board along with the fix. Here it is.
I filed down the notches where the LED board contacts the spring and that solved the problem as shown in my photo.

Title: Re: BM235 back light issue
Post by: Specmaster on February 12, 2020, 06:32:58 pm
I don't have one of these meters, I was considering it but decided against it as there was so much apparent trouble with it according to the forum. I elected to go for a Brymen BM867 and I'm very happy with it.  Those springs don't look to be a very reliable contact if they are only relying on plated contact on the edge of the board?
Title: Re: BM235 back light issue
Post by: AVGresponding on February 12, 2020, 06:42:40 pm
Isn't the EEVBlog BM235 a rebadged Brymen 235?

afaik it's the 121GW that has some issues, not the BM235.
Title: Re: BM235 back light issue
Post by: Specmaster on February 12, 2020, 06:51:22 pm
Yes it is rebadged from Brymen, but I'm sure that it also has some issues and I believe there is thread on the forum.
Title: Re: BM235 back light issue
Post by: Monkeh on February 12, 2020, 06:52:30 pm
The BM235 does not have much in the way of problems. There's been a few here and there, but you've only noticed because there's a very large cluster of owners in one place..
Title: Re: BM235 back light issue
Post by: J-R on February 12, 2020, 07:01:57 pm
One major issue I had with the BM235 was with the selector switch.  I must have inadvertently placed it between two positions for a period of a few days because the next time I went to use the meter it was very loose and would constantly glitch.  I disassembled everything and forced the plastic springs outwards for a 24 hour period and then reassembled it.  It's been fine ever since.
Title: Re: BM235 back light issue
Post by: Sparky Faraday on February 12, 2020, 07:40:53 pm
I don't know if the BM235 is just rebadged or upgraded. According to JoeQSmith who beat on it pretty mercilessly it's hard to burn out. Apparently it takes 15KV where it shouldn't be to kill it. The input board looks very robust. I don't know if that is Dave's contribution or Brymen's basic design.

Granted, the light issue is minor but important so I posted as Dave asked. The edges of the LED board have gold plating so I doubt I will have that issue again.

Gold plated springs would be nice for both the sidelights and the battery pack. Time will tell.

Also at my age my hearing isn't great so a louder buzzer or a hole/tube to let the sound out would be appreciated.

The 121GW is the meter I passed on due to so many issues primarily with the software.

For a BT meter, I suggested he beef up one of the OWON BT35+ or the BT41+ since they have pretty good BT functionality. Just making it spark-proof would probably do it.
Title: Re: BM235 back light issue
Post by: J-R on February 12, 2020, 11:03:21 pm
The EEVblog BM235 is just blue and has his sticker on it, then his custom packaging as far as I'm aware.  I believe there were one or two updates over the years to correct some minor problems.

Besides the privacy/security concerns with the Owon software, I found the meter to be of very cheap construction/quality. I doubt Dave would ever rebrand one of their meters.

The 121GW just got a new firmware update which claims to solve the logging to SD card issue.

Everyone has different priorities.  Years ago price was nearly the only thing that mattered to me, but these days I gladly spend a bit more to obtain higher quality items.  I've given away a lot of my cheap "junk" to friends/family where something is better than nothing.
Title: Re: BM235 back light issue
Post by: Sparky Faraday on February 13, 2020, 06:18:59 am
The EEVblog BM235 is just blue and has his sticker on it, then his custom packaging as far as I'm aware.  I believe there were one or two updates over the years to correct some minor problems.

Besides the privacy/security concerns with the Owon software, I found the meter to be of very cheap construction/quality. I doubt Dave would ever rebrand one of their meters.

The 121GW just got a new firmware update which claims to solve the logging to SD card issue.

Everyone has different priorities.  Years ago price was nearly the only thing that mattered to me, but these days I gladly spend a bit more to obtain higher quality items.  I've given away a lot of my cheap "junk" to friends/family where something is better than nothing.

Thanks for the reply.

Years ago money issues were much more pressing for me. I'm semi retired and figure the BM235 is the last meter I will NEED for vacuum tube audio, my motorcycle and house wiring. I just wanted something that works, so with the meter light fixed I'm cool. For logging I don't need accuracy out to 100,000 counts, mostly just trends and on-off intervals for my hot tub, finding amplifier intermittents, thermal runaway, line voltage variation, temp, etc.

Thank you to everyone who weighed in on this. Apparently I got the only one with a shaky light and glad that no one else had to deal with it.

And I'm happy to post the fix for anyone who may need it.
Title: Re: BM235 back light issue
Post by: sb42 on February 13, 2020, 09:53:39 am
You're not the only one to have had this problem with the BM235:

https://www.youtube.com/watch?v=Z6IF9wOUrw0 (https://www.youtube.com/watch?v=Z6IF9wOUrw0)
https://www.youtube.com/watch?v=SNntyelmeLA (https://www.youtube.com/watch?v=SNntyelmeLA)

(Not my videos)

I had the same with a new BM257s; it was trivial (but fiddly) to fix.
Title: Re: BM235 back light issue
Post by: Sparky Faraday on February 02, 2021, 05:40:53 am
HA! I'm not alone. It's a good meter.

I got my Fluke 77 to work reliably again and for resistance it is much faster, as well as some of the other functions. So with 2 meters to watch voltages and 2 to watch current in an output stage I can do stereo amps for current and DC offset readings.

Thanks