Just a thought - I've noticed that some DC clamp meters can get skewed by exposure to very strong magnets. It might be worth using a degausser on it to see what happens.
I don't know if you have another one to do a board swap with to see if the problem follow the daughter board or stays with the mainboard and go from there.
JU8 pin 1 looks insufficient solder on front board possibly floating. Edit: most visible at 8:08, also appears to have major solder voids on opposite side of board most visible at 9:50. I think the other side of these header pins were resoldered, motherboard side, but the daughterboard side I don't believe was touched up.
i've gotta say dave. You're top notch with product support. All of the meters i've purchased from you work perfectly. i want the 121gw but i have a bm869s to go with bm786.
Did you check if the laminated clamp core has become magnetized? That can sometimes happen if the company is working with ultra high DC currents or more likely around magnetics like in large solenoids or motors. If you have a degausser might be worth a try.
@@EEVblog2I'd suspect that as a possible cause. Just imagine the inrush current on a 15 kWh battery if they forget to precharge! That meter is probably used for some >400 A for 5 minute test or something. If confirmed might have to advise the customer to _reverse clamp meter polarity each test_ to prevent future failures.
@@WizardTimWhy would this residual magnetism continue to increase by itself? The offset went from 14A to 85A during the time it was being posted to Dave.
@@ferrumignis Good point, if it's magnetism it shouldn't be increasing unless it's being actively exposed to a high field strength, maybe the customer reported the fault to Dave awhile ago and continued to use it before getting an RMA and sending it to Dave? Otherwise it could be that the MEMs magnetometer is physically damaged by some massive > 10 kA inrush pulse, I could believe that could cause the drift without needing to be used, guess we just have to wait to see what Dave finds now I guess.
I didn't notice if you tried removing the batteries, wait a few minutes and replace them and try it, or use a different set of batteries. It can be magic.
A leaky precision amp (that AMD device?) right up there in the front end would be my guess. Try hitting it with some heat/cold and see if that dramatically changes the offset.
8:25 "Yeah, there's nothing obvious there, there's no solder joint issues that I can see" but in the video pin 1 of that 3-pin connector, top right, is clearly NOT soldered ... let's see how long it takes him to notice,
It might "ruin" a second meter, but I would try swapping parts with another working unit just out curiosity. Maybe the hall sensor in the clamp went "bad"? Looks like an interesting repair video, especially since it didn't "self-heal" after opening it.
I wonder how these BM036 clamp meters work on the VFDs? On the factory floor there are hundreds of these AC motor drives to maintain. Great video, thank you.
As you were looking at the daughter board I couldn't see any solder on one leg, of the three-leg plug that was just unsoldered from the main board. It may be soldered fine on the other side and has just not flowed through, it's visible around the other two pins though.
Great, now I've been reminded to revisit my little Uni-T to see if l can't track down its phantom voltage offset, and why its NCV went wacky. Got some good years out of it, but l liked how convenient it was
A similar thing has been happening with my cheap uni-t meter (Although at a smaller scale) . It'll be interesting to see if it's the same cause if we ever find out
What a interesting fault. another possibility if that's not read only memory would be a bit flip. My first thought would be maybe the current clamp has been magnetized by accident?
It probably doesn't make a difference but I noticed that pin 1 of the three pin header appears to only have solder on one side. The solder didn't flow through the hole to the other side of the PCB.
Dave be like, 'They are generally good meters.' Me be like, 'Finally, a recommendation.' So I ordered the BM037 and hope I won't regret this €100 purchase.
I've got a clamp meter that I bought from hazard freight that has never worked right. I can't remember what didn't work, whether it was AC or DC. But something about it was weird, I think it was AC amps always read wrong
its not that its to large of a number cause as of making the letter they said it was 7-8A then up to - 14A and it would not 0 out now its pulled it self up to 85
Wish I had one of these 8 years ago lol. I have been looking for a new meter. I was torn between an EEV blog BM 235, fluke 17B+ and those scope meters that were reviews here (not long ago I think) with the 2 inputs. I am in Canada so the EEv blog one is the most expensive.
I did notice that the Zero button did nothing. Perhaps the button contacts are faulty. I'd remove the button and try with a metal contact to see if the issue is the conductor on the button.
Maybe the meter is picking up the long awaited pole shift!!😝 Is that a genuine Analog Devices IC ? If so , which one? I tried looking it up and couldn’t find it. My bet is the mcp6002 opamp. In the circuit example of the data sheet for ac/dc test circuit, any of those capacitors in said circuit could cause all sorts of issues.
Part 2 is here. It's not magnetisation of the core. ruclips.net/video/UJ6JG4eV0nY/видео.html
Just a thought - I've noticed that some DC clamp meters can get skewed by exposure to very strong magnets. It might be worth using a degausser on it to see what happens.
Agreed, on other units degaussing is part of the procedure.
I would suspect the same.
Would that cause it to continue to go further out though?
Back in the Nokia days my phone speakers always failed when doing a generator load test
@@Zanthum Continued use in the vicinity of a high power magnet.
I don't know if you have another one to do a board swap with to see if the problem follow the daughter board or stays with the mainboard and go from there.
JU8 pin 1 looks insufficient solder on front board possibly floating.
Edit: most visible at 8:08, also appears to have major solder voids on opposite side of board most visible at 9:50. I think the other side of these header pins were resoldered, motherboard side, but the daughterboard side I don't believe was touched up.
Yeah; JU8 looks worrying for sure; though it does seem strange that remove + reinsert would continue at the same offset..
No solder on the top side of a plated through connector hole is not uncommon.
@@EEVblog2 Failed trough plating barrel is also not uncommon.
i've gotta say dave. You're top notch with product support. All of the meters i've purchased from you work perfectly. i want the 121gw but i have a bm869s to go with bm786.
The missing calibration procedures etc. reminds me of We really need riggt to repair laws
Shocking that an engineer licensed dealer can't even access this even with an NDA
demagnetize the clamp. Clamp it a few days on one phase of your home circuit.
Did you check if the laminated clamp core has become magnetized? That can sometimes happen if the company is working with ultra high DC currents or more likely around magnetics like in large solenoids or motors. If you have a degausser might be worth a try.
I've asked them. The company makes custom high capacity battery packs, like 15kWh stuff.
@@EEVblog2I'd suspect that as a possible cause. Just imagine the inrush current on a 15 kWh battery if they forget to precharge! That meter is probably used for some >400 A for 5 minute test or something. If confirmed might have to advise the customer to _reverse clamp meter polarity each test_ to prevent future failures.
@@WizardTimWhy would this residual magnetism continue to increase by itself? The offset went from 14A to 85A during the time it was being posted to Dave.
@@ferrumignis Good point, if it's magnetism it shouldn't be increasing unless it's being actively exposed to a high field strength, maybe the customer reported the fault to Dave awhile ago and continued to use it before getting an RMA and sending it to Dave? Otherwise it could be that the MEMs magnetometer is physically damaged by some massive > 10 kA inrush pulse, I could believe that could cause the drift without needing to be used, guess we just have to wait to see what Dave finds now I guess.
I didn't expect to see so many cheap trim pots in anything made by Brymen.
I didn't notice if you tried removing the batteries, wait a few minutes and replace them and try it, or use a different set of batteries. It can be magic.
A leaky precision amp (that AMD device?) right up there in the front end would be my guess. Try hitting it with some heat/cold and see if that dramatically changes the offset.
AMD? It’s an Analog Devices part.
8:25 "Yeah, there's nothing obvious there, there's no solder joint issues that I can see" but in the video pin 1 of that 3-pin connector, top right, is clearly NOT soldered ... let's see how long it takes him to notice,
Okay, at 9:21 is looks like it's soldered on the BACK of the board, but it sure looks dodgy from the component side ...
No solder on the top side of a plated through connector hole is not uncommon.
Hey, if you have another try swap the boards one by one, to isolate the bad board, then compare both
it could be the hall device
Swap board with one known to work and issolate fault. Fun times 😊
It might "ruin" a second meter, but I would try swapping parts with another working unit just out curiosity.
Maybe the hall sensor in the clamp went "bad"?
Looks like an interesting repair video, especially since it didn't "self-heal" after opening it.
I wonder how these BM036 clamp meters work on the VFDs? On the factory floor there are hundreds of these AC motor drives to maintain. Great video, thank you.
Didn't even know this one was released, been looking forward to this meter for my electrical work... Been using those cheap uni-t clamps
As you were looking at the daughter board I couldn't see any solder on one leg, of the three-leg plug that was just unsoldered from the main board. It may be soldered fine on the other side and has just not flowed through, it's visible around the other two pins though.
Great, now I've been reminded to revisit my little Uni-T to see if l can't track down its phantom voltage offset, and why its NCV went wacky. Got some good years out of it, but l liked how convenient it was
Did you try zero button in the ACA mode and did it work? If not, could be defective zero button or related circuit.
Does this clamp meter model record peak amps reliably - I need on of those!
Dave couldn't find the error, I don't believe it 😮
"Yeah... yeah... I partner with and resell assholes' stuff!"
Weird, I'd be interested to know the fault. The serial number on my BM036 is very close to this one.
A similar thing has been happening with my cheap uni-t meter (Although at a smaller scale) . It'll be interesting to see if it's the same cause if we ever find out
What a interesting fault. another possibility if that's not read only memory would be a bit flip. My first thought would be maybe the current clamp has been magnetized by accident?
It probably doesn't make a difference but I noticed that pin 1 of the three pin header appears to only have solder on one side. The solder didn't flow through the hole to the other side of the PCB.
Dave be like, 'They are generally good meters.' Me be like, 'Finally, a recommendation.' So I ordered the BM037 and hope I won't regret this €100 purchase.
I've got a clamp meter that I bought from hazard freight that has never worked right. I can't remember what didn't work, whether it was AC or DC. But something about it was weird, I think it was AC amps always read wrong
its not that its to large of a number cause as of making the letter they said it was 7-8A then up to - 14A and it would not 0 out now its pulled it self up to 85
There's only a couple of signals from daughter board. Could compare to a known good unit.
One of the pot maybe has grown a resistance bridge?
Wish I had one of these 8 years ago lol. I have been looking for a new meter. I was torn between an EEV blog BM 235, fluke 17B+ and those scope meters that were reviews here (not long ago I think) with the 2 inputs. I am in Canada so the EEv blog one is the most expensive.
This is very likely component failure, probably a capacitor or Opamp/ADC with a manufacturing defect that slipped through testing
Looks like there are several dodgy solder joints, there’s quite a few there I would have reflowed.
I did notice that the Zero button did nothing. Perhaps the button contacts are faulty. I'd remove the button and try with a metal contact to see if the issue is the conductor on the button.
I think the zero button works only when the reading is near to zero. Not on large variations.
So does Brymen give you credit for defects or do you have to eat that?
Dave seems to have iGNAWed that question, I guess that he can CHEWs to do that. 😏
did c31 have a crack along the solder joint?
Maybe the meter is picking up the long awaited pole shift!!😝
Is that a genuine Analog Devices IC ? If so , which one? I tried looking it up and couldn’t find it.
My bet is the mcp6002 opamp. In the circuit example of the data sheet for ac/dc test circuit, any of those capacitors in said circuit could cause all sorts of issues.
Dave, have you measured the clamp coils? I think they have to be fairly close to each other.
I might be misunderstanding your point, but DC current does not (can not) use coils, it uses hall sensors.
The clamp jaws have coils in them; I don't think Dave tested them. I couldn't see anything obvious on the boards.
@@Joseph-j9r7g The coils are used for measuring AC current.
Is R79 missing, or on the other side perhaps?
Slowly getting magnetized
From what? How did it go from 14A to 85A offset whilst it was being posted to Dave?
May capacitor be faulty guessing thanks
hmmm why dc clamp meter is more expensive then ac only clamp meter🤔. if it just a piece of software, why double the price?😓
that daughter board sure as heck looked like it was meant to come out of that socket you unsoldered are you sure its just not stuck or something ?
Just return it to the customer with a calculator and tell them to subtract the difference.. ;-)
1.21 Gigawatts!!!
over limit, there is no load.
It's frickin' solar roadways curse Dave. I've told you not to mess with those guys!!!
Ugh.
Is your voice pitch getting higher?
Maybe he's Australian?!
Davina is mid-transition.
Just refund them and give them and huge discount on a better ndmeter
Should have brought a uni t😅
Gonzalez Eric Thomas Jose Jackson Steven
Free energy! :)
Nice! No more porn bots!
At the time of typing this, two comments below you is from one. lol
I thought OL was Open Loop on meters.
"Ower range" would be a better phrase. It reads OL on current and volt over ranges
"Open loop" would only make sense on a resistance or diode test range, not on voltage or current ranges.
Overload innit, although open line seem popular with youtube "techs" 🤣
Sometime it's Over or Outside Limit.🤔
@@brucepickess8097 how about Out(of)Luck
So, yeah?!