Brymen BM 235 Startup issues - Page 1
Forum section: electronics / testgear

author: derree
author_rank: Contributor
timestamp: January 01, 2020, 11:10:59 am
content: Hi everybody!I am a hamradio and general electronics enthusiast and quite happy with my Brymen BM 235, at least until 2 weeks ago.I always used rechargeable AAA batteries (eneloops) in all of my multimeters, never had a problem. The BM 235seems to stay stuck in the startup process, means when I switch from "off" to a function, the LCD shows all segments as black (which is normal for about half a second), but the device never pulls through to the selected function. The display stays in the state of all segments black.I suspected the eneloops to cause this, as they by default have a voltage of 1,2V, whereas alkalines have a voltage of 1,5V, which I suspected to make problems during a phase of higher power requirements during startup of the multimeter.It seems to be better, but now and then the BM 235 shows this behavior.Has anybody an idea what could cause this problem?all have a nice day!Derree

author: Specmaster
author_rank: Super Contributor
timestamp: January 01, 2020, 11:29:30 am
content: A simple way to test your theory is to replace the eneloops with conventional alkalines and see how it behaves. I think you might well be right as a rechargeable has a maximum voltage of 1.2V whereas a alkaline is around 1.6V so with a new set of batteries you are already .8V lower and I believe that the alkaline is capable of supplying a larger starting current.

author: wraper
author_rank: Unknown
timestamp: January 01, 2020, 11:37:36 am
content: Quote from: Specmaster on January 01, 2020, 11:29:30 amBS, freshly charged NiMH has around 1.45V voltage but fresh alkaline around 1.55V. Nonetheless even at 1.2V per battery meter must work fine unless it's faulty.

author: Specmaster
author_rank: Super Contributor
timestamp: January 01, 2020, 12:12:27 pm
content: Quote from: wraper on January 01, 2020, 11:37:36 amJust taken a new AAA alkaline from a sealed pack and it measures 1.595080V so it is much nearer to 1.6V than it is 1.5V, also the maH capacity of alkaline is higher than a eneloop, typically 1,200maH alkaline as opposed to 800maH of a eneloop. Reference is from Wikipedia

author: derree
author_rank: Contributor
timestamp: January 01, 2020, 12:19:42 pm
content: Hi!Thank you both very much for your replies.I have changed the batteries from eneloops to fresh alkalines, and I will observe the behaviour of the multimeter.I have measured the voltage of other fresh charged aaa eneloops and fresh energizer aaa batteries.Results:eneloops about 1,3Valkalines about 1,56VI have also measured the voltage of other freshly charged NiMH aaa, which also gave me about 1,3V.I also think, that the meter should work fine with a voltage as low as 1,2V, so I assume there is something wrong with my brymen.Thank you all for your help, and I wish you a happy new year btw!Derree

author: Specmaster
author_rank: Super Contributor
timestamp: January 01, 2020, 12:38:03 pm
content: I think you will find that the 1.2V might well be very suspect with regard to the meter working correctly, in particular with regard to its starting up from cold so to speak because the data sheethttps://brymen.eu/shop/bm235/clearly states that the meter displays "Low Battery" warning at around 2.5V so if your batteries are reading 1.2V each, then you are already 0.1 Volt lower.Personally I always use alkaline batteries in my meters.

author: Helix70
author_rank: Unknown
timestamp: January 01, 2020, 01:23:33 pm
content: Might need some batterisers!

author: Specmaster
author_rank: Super Contributor
timestamp: January 01, 2020, 01:29:16 pm
content: Quote from: Helix70 on January 01, 2020, 01:23:33 pm

author: wraper
author_rank: Unknown
timestamp: January 01, 2020, 02:28:53 pm
content: Quote from: derree on January 01, 2020, 12:19:42 pmThen it was not just charged but stayed some time after charting.

author: wraper
author_rank: Unknown
timestamp: January 01, 2020, 02:33:32 pm
content: Sounds more like problem with rotary switch.

author: NoisyBoy
author_rank: Frequent Contributor
timestamp: January 01, 2020, 07:52:38 pm
content: I would guess the meter is defective. I have yet seen any electronics not accepting rechargeable batteries, that is assuming your rechargeables are freshly charged.

author: derree
author_rank: Contributor
timestamp: January 02, 2020, 08:31:01 pm
content: Hello everybody,The meter works perfectly with the alkalines, and starts to produce the mentioned behaviour when used with the eneloops. I am thinking that the eneloops start to fail after one year of usage. Time to get some new rechargeables!

author: Specmaster
author_rank: Super Contributor
timestamp: January 02, 2020, 08:48:00 pm
content: Thanks for letting us all know, I know that I have never had much success with rechargeable batteries of any make, as mentioned earlier, they seem to struggle to deliver peak currents when required.

author: wraper
author_rank: Unknown
timestamp: January 02, 2020, 10:21:31 pm
content: Quote from: Specmaster on January 02, 2020, 08:48:00 pmNonsense. NiMH have several times lower internal resistance than alkaline and thus can deal with much higher loads. Look at that graph above in my post. Try drawing a few amps from alkaline. At 1A they are virtually useless, even at 0.5 A they still suck a lot.Typical alkaline discharge curve.

author: wraper
author_rank: Unknown
timestamp: January 02, 2020, 10:24:28 pm
content: Also if meter struggles at 1.3V per battery, it means that more than half of Alkaline capacity will go to waste.

author: GLouie
author_rank: Regular Contributor
timestamp: January 02, 2020, 10:41:17 pm
content: I'm using white Eneloops in my Dave-branded BM235 and am not having any problems, even after some months.I use Eneloops whenever possible due to repeated leakage problems with all alkalines.

author: bc888
author_rank: Regular Contributor
timestamp: January 03, 2020, 12:25:04 am
content: Same as Glouis. I use the BM235 meter infrequently as I have a Tek 850 that stays on the desk ready to grab, same set of eneloops(white) for a couple months in the bm235, meter still working as of 2 days back. Which doesn't tell anyone what the batteries are currently measuring of course and therin lies the question.

author: Specmaster
author_rank: Super Contributor
timestamp: January 03, 2020, 01:56:32 am
content: Rechargeable batteries when new are completely different kettle of fish to rechargeable batteries that are not so new clearly as the OP has already reported, the meter is performing perfectly on alkaline batteries.I have tried to use rechargeable batteries myself on a many occasions and it has been my experience that once they are a few months old, they do not seem to be as effective as they were and then at that stage alkaline just seem to be a better bet all round and in general more cost effective as the rechargeables are that much more expensive to begin with.I have tried many makes and capacities and the end result is the same, a few charging cycles and the performance drops off, maybe I've unlucky and have brought batteries that had been shelf sitting too long I don't know.

author: wraper
author_rank: Unknown
timestamp: January 03, 2020, 02:16:24 am
content: Quote from: Specmaster on January 03, 2020, 01:56:32 amRegular NiMH have extremely high self discharge rate. After a half a hear they will be empty on their own, without any load. Eneloop does not have this issue. Also unless you do something ridiculous to them, they'll last hundreds of recharge cycles without any noticeable degradation. BTW just buy white IKEA LADDA, they are Eneloop pro in disguise for a fraction of the price.https://www.ikea.com/gb/en/p/ladda-rechargeable-battery-70303876/https://www.ikea.com/gb/en/p/ladda-rechargeable-battery-90303880/Also they don't leak. Alkalines leaking twice in my Keysight U1272A and back cover replacement was enough to decide never buying them again.QuoteThat's some first class nonsense BTW. They easily last for more than a decade if treated properly.

author: Specmaster
author_rank: Super Contributor
timestamp: January 03, 2020, 02:32:01 am
content: @wraper Next time I go to Ikea I'll grab some AA's and give them a try then and see how I get on with them.

author: Miti
author_rank: Super Contributor
timestamp: January 03, 2020, 02:50:34 am
content: Quote from: derree on January 01, 2020, 11:10:59 amA phase of higher power during startup? Why would that be? I don't expect that instrument to draw more than 10-15mA, unless it is defective.A short inrush current to charge some capacitors, if at all, shouldn't be a problem either.I have an old Protek HC81 that does exactly that if I push a button right after the power on, during the display test phase. It stays there with all the segments turned on, until I release that button.Can you try the same thing with the alkaline batteries? Just push any button during the display test and see if you can duplicate your issue.You may have some dirty button contacts, or some moisture.

author: derree
author_rank: Contributor
timestamp: January 03, 2020, 05:28:46 am
content: Quote from: Miti on January 03, 2020, 02:50:34 amHi,I already tried that, pressing some of the buttons during startup with both, alkalines and eneloops. Same result: 2 times of 10, the meter with eneloops is stuck in the boot process, with alkalines the meter pulls through every single time.I have to correct myself, the eneloops are older than a year, it was my second batch bought in September 2017, so we are talking about 2 years now. My fault!

author: Specmaster
author_rank: Super Contributor
timestamp: January 03, 2020, 10:36:05 am
content: Any idea how many times they were recharged during that time? So far my experience has shown with batteries that have been recharged 2 or 3 times and then not used for while fail next time they are charged with error codes on the battery charger. Whereas alkaline batteries are quite happy with periods of non-use Ni-MH arent.

author: wraper
author_rank: Unknown
timestamp: January 03, 2020, 10:44:23 am
content: Quote from: Specmaster on January 03, 2020, 10:36:05 amSounds like your charger is (probably faulty) crap. It's your charger what fails, not batteries.

author: wraper
author_rank: Unknown
timestamp: January 03, 2020, 10:47:56 am
content: Quote from: derree on January 03, 2020, 05:28:46 amAttach to lab PSU instead and try switching it on with different voltages. In any case, hanging on startup is failure. If batteries provide too low voltage, it still should not hang on power on.

author: Specmaster
author_rank: Super Contributor
timestamp: January 03, 2020, 10:50:04 am
content: Quote from: wraper on January 03, 2020, 10:44:23 amNot really, because I have a number of different chargers, and is the SAME batteries that fail each time with any of the chargers.

author: wraper
author_rank: Unknown
timestamp: January 03, 2020, 11:04:33 am
content: Quote from: Specmaster on January 03, 2020, 10:50:04 amUnless you bought some extraordinary crappy batteries, this sounds really strange.

author: Ohm
author_rank: Newbie
timestamp: January 04, 2020, 01:09:35 am
content: https://www.eevblog.com/forum/testgear/fluke-289-meter/Somehow my name got change from dab147315 but this was my first post and change all my meters over to lithium batteries and no problem with that Fluke 289 to this point.

author: paulbt
author_rank: Regular Contributor
timestamp: November 11, 2020, 03:26:25 pm
content: Hi, everyone !I recently bought a Brymen 235 and while I was playing around with it, I was curious if it has any power-on options like Flukes. The only thing that I found was while holding "HOLD" button when turning on - it displayed "9". The manual does not mention anything about this. Does anybody knows what it means?

author: jordanp123
author_rank: Regular Contributor
timestamp: July 01, 2022, 01:06:20 pm
content: My BM235 just started doing the same thing. Although I can't even get mine to fully boot. It'll just come up to the start up screen with the display test and never leave. If I up the voltage it'll eventually give me the inEr message and beep but thats all. This was actually a spare meter I bought for just in the occasions I needed multiple meters....which was yesterday. Any one have any ideas?

author: slburris
author_rank: Frequent Contributor
timestamp: August 15, 2022, 09:22:44 pm
content: In fact my BM235 is displaying the same symptoms. Changed to fresh batteries, no dice, hangs in bootup. So sad that it'shaving problems -- it hasn't been abused in any way, but it's broken now. Does the firmware bit rot over time? Who knows. When I press the HOLD key at power up, it displays "C", so it's not fully dead.Oh well, guess I'll use my Fluke meter for now, as I am not up to trying to troubleshoot this down to the component level right now.

author: J-R
author_rank: Super Contributor
timestamp: August 17, 2022, 02:55:24 am
content: Surely the first step is take it apart and clean the wipers and contacts?

author: cbianco
author_rank: Newbie
timestamp: November 04, 2022, 04:45:36 pm
content: My EEVBlog BM235 just started doing the same thing as well: it starts up, but gets stuck on the LCD test screen and is completely unresponsive. If I hold down the HOLD key at startup, mine shows 9, which I think is just the firmware version.I tried fresh batteries, checked fuses, took it apart, did a visual inspection of the board, cleaned the wipers & contacts, and scoured google for solutions. This thread seems is the only place where I found the same issue mentioned, so adding my observations:I found a highly impractical workaround, at least for my case: I noticed is that if I hooked it up to a DC power supply, and LOWERED the voltage to about 2.1 volts, it started up normally (albeit with a low battery warning and a dim screen)... Turning the voltage back up to 3V got it behaving properly as far as I can tell, but the problem returned after powering it off. I could also get it to start up properly if I very briefly disconnected the battery (probably because that briefly dropped the voltage via some partially-discharged capacitor)... so maybe the problem has to do with some transient voltage during startup(?) - maybe a capacitor that' s not charging? I'm a mech eng, so out of my depth with this stuff, but maybe that can help someone smarter than me to properly diagnose the problem...

author: wraper
author_rank: Unknown
timestamp: November 04, 2022, 08:37:03 pm
content: ^Seems more like it fails some sort of self testing but lowering the voltage lets it pass. Try to get it working and check if all functions are within spec to possibly narrow down the issue.

author: cbianco
author_rank: Newbie
timestamp: November 07, 2022, 02:33:18 pm
content: thanks for the suggestion! I tested every function I could (AC/DC voltage, current, resistance, capacitance, diode), and once I get it to start, everything seems to work fine - at least within the limits of my crude testing equipment.I found another way to get it to start up properly: if I cool it down (ie: in my freezer), it works without issue - other than the sluggish LCD. I tried this with a 3V DC power supply (so nothing to do with cold batteries), and didn't have to drop the voltage to get it to start up normally. Once it's back up to room temperature, the problem is back.