The more I watch of you, Big Clive, AvE and Fran, the more I learn... oh and I am 63 now and retired- you and your fellow TH-camrs are my Second University. Thank You.
All these repair videos that guys like Dave and Shahriar do make me wonder how many millions or billions of dollars worth of equipment ends up scrapped or junked or collecting dust because of the failures of single sub-penny components. I remember hearing so often that it wasn't worth fixing things, or people should just swap boards, but that seems so wasteful now. But I guess time is money, so that factors in.
Yeah, it's crazy. I was on Skype call with my best friend after my laptop's charging circuit died and they said something like "oh, about time to get a new one then". And I was shocked! Hell no, I'm going to rip this thing apart and see what's going wrong. Turns out a MOSFET was blown and I had a replacement part, and it only took an hour or so to get a new one in.
An hour of someone's time for component level repair is worth anything from $100 to $300. Older laptops or cheaper laptops would be easily totaled at that rate.
people throw out lcd monitors all the time because of 20 cent capacitors. back in the day you could find crt tvs and monitors on curbs for bad transistors, those only cost a buck or two a well.
First you pay someone to diagnose the problem (base pay + benefits + social security + Medicare + Federal Unemployment taxes + State Unemployment taxes + Workers Comp +++ etc.). Then you pay someone to fix it (see above). Assuming it can be fixed. And at the end you have a used piece of equipment that YOU have to warranty for when the next item fails (because the owner will never believe you did not break the component on a completely different board/area while working on it). Economics do not really support the effort UNLESS you are a small company (or single individual) doing the work. Or you can charge a lot for the work, such as repairing really high-end or rare pieces of equipment. Sad statement on economics. Taxed to purgatory then further litigated into oblivion.
Mass production has a percentage of return rate due to faulty parts. The first one is pretty good after thousands. Maybe put a signature on it and sell it as a refurbished limited edition one? :P Great video ;)
That's a good idea, he could auction it as a prize or something ... I'm sure someone out of 350k people would be interested in having a genuine, as-seen-on-youtube, fixed-by-dave item!
Personally repaired by Dave? That is not refurbished, that is "made perfect..." or "quality assurance by Dave's own hands." It's like those flags that have "flown over the White House", they run them up, count to ten, take them down and bag them up. Market as "Used by Dave himself." or "Checked for accuracy..." or "Tested by Dave himself." It should be worth at least a 2X premium. 3:-)
I've torn and had surgery on my right leg's acl before. For Dave to diag this gents returned multimeter, on video, takes a maximum amount of character. good on ya Dave. Get well soon.
+EEVblog I was young and I didn't stick to the pt properly. No pain but no full extension. I'm missing probably 3-8 degrees to full extension of the knee.
I thought that about Dave repairing the item on film. But then in most situations a sane person within this industry accepts sods law, like Dave admitted. It's just the way it is. It's also interesting to observe those who will not take responsibility or criticism and see it as a sign of weakness or what have you and do what they can to shun similar. Some people are glass half empty and some are glass half full with life's choices.
Opened up my one while watching this - all the soldering is absolutely perfect including L3. I noticed L3 is right next to an alignment pillar on the case and there is a larger pillar on the back cover that goes over it which would put it right over L3. It could be possible that a compressive force on the case in that corner could push that onto the component and break it...? Regardless - I love the meter and recommend it!
I was thinking that also, based on that pillar and the isolation gap, there could be more torque on those components than expected. I suggest taking another look at the other inductor, it looked to me like it might be cracked also.
I have little ideas about how that tiny world of chips work. But I find this stuff fascinating and enjoyed watching this teardown and troubleshooting. Good find and repair.
I went over a bryman, not same model.m it also had weird intermittent issues as well. Repair shop never figured it out either. The distributor needed refunding my friend. It happens once in a while. Sorry about the ACL, I had that surgery. Had bad after affects during recover. Not the worst surgery but not the most pleasant. My shoulder was worse in pain but faster recovery. Wish you luck with that surgery.
+EEVblog I'd say yes considering my situation. ACL and Meniscus are the common sort knee injuries. But being Type 1 diabetic w/ compromised immune system slowed down recovery. Just started rehab later then expected from swelling taking longer to go down, but once it did it was full speed ahead. Unfortunate I also had torn the Meniscus and because I had to fight insurance for two years for surgery approval it became beyond repair. So that bothers me, but ACL is good. I have a knee replacement approved, but don't want that until I feel it's the last option. Key things are get it done as soon as possible, use a good sport surgeon that has done many of them.Don't slack off on rehab! My shoulder recovered better then original, but I was rigorous with rehabilitation. Everyone will tell you take rehab serious to build it back up and it should be fine, I know people that were lazy with rehab and years later regret it. Good luck, I'm sure you won't slack off with rehab and should be fine.
Is the small board with the input jacks well supported on the back by the case? It looks as if the red connector wire near the ground jack, that has no relief bend in it, could pull on the main board a little every time something is plugged into the common jack. The connection of the wire on the main board is right besides the inductor and the relief cut under the inductor will make any stresses to the board there go right through the inductor. This really looks like a design oversight.
Maybe a moisture problem? Could crack the housing during soldering but keep contact so it would pass the tests (and as far as I remember it even cracked on the bottom side, so no real clue for visual tests either). Because of the reduced stability it is however no longer really vibration resistant (didn't look like it was glued down) so shipping could have broken the part in the end.
Great video Dave. I find the way you verbally annotate your thought process to be very informative. I look forward to seeing more repair videos in the future.. Thumbs up!
I think those pads look awfully big for those components, when you make solder strech this far, it's prone to crack under mechanical tension. Solder ain't flexible.
Do you always get this lucky with easily identifiable problems? Almost every time I open something up I'm hoping it will be just a quick simple component replacement, but it usually isn't lol
lol even though I have almost zero electronics skill compared to this guy, I always hope the same thing. Hoping for some leaking caps, brown spots etc.
I have a repair shop for mostly SMD components, and it's 90% cracked solder joints or component solder joints just like this. My microscope is my friend. Then mechanical parts like pots, switches, then transistors.
In case of such warranty claims right after using the product for the first time, it's very often a faulty component or some mechanical problem that happened during the production (bad connection or even a connector that lies around). The things will be different if one fixes only things that worked fine until now.
I guess the componen was already slightly cracked or weakened during production or soldering but still held together well enough to pass testing without problems. Then when it was shipped, it was in the cargo room of an airplane at high altitude, so it got really cold, I think up to -50°C or something at travel altitude? So in cold temperatures, things contract and in heat they expand. The component, when it was soldered, expanded slightly and when the solder colled down, it was held in place in this expanded state. At room temperature, there already was stress on the weakened component and when it was cooled down to the flight temperatures, the contraction force was great enough to finally rip the weakened component in half
Airplane cargo holds don't get down to -50°C. They have a single pressure vessel that contains crew, passenger and cargo areas. The whole vessel is pressurized, and therefore receives conditioned air. In some planes, the under-floor cargo area is sealed for fire protection and has its temperature loosely controlled by a surrounding air jacket, but none are open to external atmosphere.
Yep, I once had to leave a trailer full of Post Raisin Bran at the rest area in the Virgin River Gorge for a week while waiting on a part. 100 degrees + every day. Don't know how hot it got inside that trailer sitting in the parking lot.
Sorry to hear about your knee. I'm fighting with my knee as well after a long bike ride, the bloody thing hurts like hell still after 2 weeks. Hope you will get well soon. :)
Nothing is perfect. That is a very low failure rate. Strange how that inductor broke off like that. I wonder if there was pressure on the area where the inductor broke, or high voltage blew it.
I agree Dave,one out of a thou,send him a new one,no problem. Once you mess up a knee you usually end up with a life time of problems no more pro football for you guy! stick it in the freezer and see if it works,or heat it up in the oven. I got a RC Trawler that the electronics were dipped in of all things bees wax,try and heat that to check the solder connection.Its all through hole stuff. I tried penetrating the wax to test and ended up with a sticky mess. The boat is considered a collectable now,it was manufactured in Germany. I read up on these and apparently they leak and it shorts out the circuit board reguardless of the wax. I see a fireboat offered simular to these,not the same country of origin. I decided to move it up to the new age and chopped out that old technology and am updating it to all modern RC equipment under the hood. It shouldnt affect the collectability,if anything it increases the reliability and makes it more of a Hobby grade RC boat instead of a toy.
interesting points ,if anyone else needs to find out about repair board try Saankramer Electronic Magazine System (do a google search ) ? Ive heard some extraordinary things about it and my mate got excellent results with it.
4 years later, still waiting for a reply from the eevblog shop support for my bm235 purchased from there, that has been dead since 6 months after purchase.
I used to work in physical therapy. I saw so many people go down hill after knee surgery (as well as athletes). Please skip the surgery if you can or work really hard to get back on your feet asap.
That's not a good advice. If surgery is necessary he needs to take it. No offence, but you're not a doctor and ACL can have complications if not treated right. It's just about the stupidest advice you can give.
aserta Im saying skip the surgery if thats an option. as in the doctor says "get surgery of do these exercises for n months." So many people (americans at least) jump to surgery and don't even ask if there is a plan B.
You can get by fine without ACL surgery if you live a fairly sedentary lifestyle, and maybe just run or cycle for exercise or something. But anything else requiring any sort of twisting action will be out the question. eg. playing with kids, outdoor stuff, etc. I did this injury 7 month ago, and I've popped my knee even in the kitchen just pivoting around.
I'm speaking to the surgeon tomorrow. But I already know it's entirely optional. I could win the tour de france or an ultra marathon with no ACL. But play ball with my kids in the backyard, probably not very well.
Enjoyed that very much. It certainly adds value to your product , because of your honesty. If I did not already have several multi meters, I would be tempted to buy one of yours. :-)
I have seen that happen with stale and mishandled parts, where the tinning on the part has oxydized before we got it in to the SMT pick and place. Oxydized solders will cause localised heating.
It's a case by case (injury degrees), how determined you are, mentally, and how good the doctor is with his/her pointy bit. Tore the ACL on my left, twisted (never really understood what that term meant, getting the feeling it was medical slang) on the other leg, chipped my knee caps (legs went backwards) and after i had both legs on lock because of fluid, it took me 7 months to get in a functional state after the surgery. By functional i mean i was able to run with some discomfort and in the winter knees (to this day) get colder than the rest of my body. Now, i was a kid back then, so, your mileage may vary. I would alleviate pain with warm water compresses or hot baths, about a year's worth after. Either way, try and find a good doctor (not sure how Australian system works), and follow their instructions. Oh and, be light on your feet, you can get your other leg injured by trying to manage the other. It's really stupid and sometimes it happens, my doc told me it happens quite often, so, if you have to suffer crutches, suffer them, soft or hard bracing depending on how severe it is.
I snapped my ACL about 6 years ago while skiing in Switzerland, luckily not much pain but a load of swelling. Got back to UK and had it repaired on NHS (hamstring graft for those following the technical side) and I ski on it hard and fast ever since. Sometimes I can feel it but mostly good. There is a new procedure I saw this month - www.themichelicenter.com/revolutionizing-the-acl-surgery/ Hope you (and Dave) heal soon.
@@SoftBreadSoft It shouldn't need strain relief. It's going from one board to another with both boards hard mounted to the same chassis. There's no strain on the wire.
I've seen similar in amplifier boards. When the right tune is played the board gets into resonance and the joints or the surface mounted parts break. With a gap underneath it's even more likely that this part will break. With a daughter board only supported on the edges makes it more likely things like that happen.
I have a UNI-T, which I'm quite happy with for the budget I had at the time, but there's no rear guard input safety protection to speak of (I think as I recall Dave's already done a teardown of that machine?) - This BM235 looks a really beefy chap in Comparison, no wonder it's reflected in the Price Tag (comparatively speaking).
I think this might have happened at the assembly after all. Board was automatically calibrated and then put in the case. Components on the corners of the board or next to similar spots (cutout for the input jack in this case) sometimes get mechanical stress applied because something (or someone ;) )goes wrong and pushes on them during an assembly step. I work in an electronics plant, we get such failures from time to time when testing the assembled product. The components are usually ripped right off, leaving only the ends soldered to the pads just like it was on this unit.
Yes this happens. I found one 0805 resistor with the same problem (was a Panasonic resistor) But was just one of over then thousand resistors of that model I used.
As a normal person not an old movie nerd, I had to look up the mass turbulence thing, I can see now why Dave would get irrationally upset of a reboot of an inconsequential movie.
EEVblog Not really, maybe inconsequential is a bit harsh though. I am only expressing an opinion, I personally can't see what the fuss is about, I don't really do obsessive.
given the "apparent" rarity of a necessary inspection and repair of this, it's practically a bonus to have the man himself fix it, especially with the branding printed on it. Did you autograph it with a "repaired by" sticker or anything?
Well, even 0.3% is not as good as 0.1% :-) Looks like it is really difficult to get very accurate capacitors. I could only find some from metrologic companies, but these costs 1k USD and more (but of course, they are even more accurate and with certificate etc.).
You can't flip it over. The actual trace that comes from inside, is tried to the cap end. So in this case, it's gonsky. Also, it was mechanical stress. It went in hot, so the piece was hot and expanded, and when it cooled, it cracked. I've seen this once before almost identical failure.
My BM235 has the same problem. Mine has been working fine for a number of years then one day started doing strange things exactly as Dave explaned and I found the same L3 has come off the solder pad.
Hi all! I have a question specifically for Dave at the EEVBLOG. I have purchased a BM235 branded eevblog from amazon here in the UK under a year ago. I seem to have an issue with it at the moment where the meter seems to not give correct voltage measurement readings in normal V (DC) mode. The unit in this same V auto mode, throws a wobbly when I press the range button 3 times. Briefly I can see 'insersion error' and acts as if I have wrong probes inserted even if I have no probes! It does however show voltage readings for DC correctly using low impedance mode. Also, continuity mode without probes and with, displays a short. I have made a video and will upload it at some point today. I have seen similar issues with the dial which was posted a while back. Nothing I know has happened to the meter to cause this issue. I will post on the forum also soon.
Hi Dave, i'm a great fan of your videos (and your great knowledge). But i think you're wrong on one issue here: the component placement print. Yes, it is good, old fashioned silk screen! no dot matrix here. The pattern you can see in the microscope is the nylon screen used for printing. All silk screen prints shows this pattern if you enlarge them. It's not half-tone screen like in a printed photo. (It is possible to print halftone images with silk screen, with half tone raster (screen), in this case the rule of thumb is that the halftone image should have half the lines of the silk. i.e. a silk (nylon that is) with 100 threads/inch, wil print an image with 50 lines/inch. Quite a coarse quality, as seen on t-shirts.
It looks like where L2 and L3 are on the board with the separation slots cutout, only leaves a couple of millimeters of board left, assuming that the boards are tested before being assembled into the case it wouldn't take much pressure to flex the board causing this damage if the assembler wasn't careful, just an observation, I don't have access to the board to confirm this possibility though.
Сделайте пожалуйста на этот обзор , с разборкой - Brymen BM869s . Как это у вас называется - REPAIR ? Правда я ничерта не понимаю что вы говорите , но все равно интересно вас смотреть )
Looks more like physical impact damage to me - the component is sheared at one end and torn off the solder at the other - at 15:30 you can see the solder fillet appears to have been bent slightly down on the left side, also consistent with the component twisting off the pad. This could have happened between bed-of-nails test of the populated boards and assembly into the housing. The manufacturer will know the exact sequence. The damaged part is nearest the edge of the board - first to take an impact - those black plastic parts are part of the case? and were not able to protect the naked PCB. It could have also occurred when the current shunt or red wire were fitted - slip of a soldering iron - looking at the solder in the vias I assume manual assembly of those parts.
Interesting. I'm always amazed that things like this don't happen all the time, there are so many components to fail. Maybe it was cracked because of too much down pressure on the pick and place tool?
I think you broke it by taking it of. Inductors are often very fragile. Sometimes the Parts stand up very slightly, especially Inductors. Its kind of a tombstone but the part stays on the solder and can still have contact. We call them "Auflieger", which translates into something like "lays-on", because they still lay on the PCB.
I ordered a BM235 from tme.eu, seems to have the same fault and has arrived DOA. Kind of put off the multimeter a little now after seeing this video before mine even arrived :).
Oh sweet I really want a EEVBlog multimeter now I might see it on here being repaired. Although like ya said most likely a one off which I hope as well. :)
With the crazy number of components in modern devices its amazing to me that this kind of thing isn't way more common. When you think about it the percentage failure is actually low.
Arek R. I don't really mean just this device. I'm thinking more any given device has hundreds if not thousands of components with that many points of failure if not multiple ones for each component. Then think of how many devices you have in your daily life. Its amazing that stuff isn't exploding left and right.
Think of computer motherboards, or ever server boards like that 8 PCI-E slot one on LinusTechTips. There's some ridiculous number of components with miniscule pin pitch and several layers in the board. But then also think about the cheap Chinese crap that just about works through its usable life and is planned to be obsolete.
My $.02 guess is that the ferrite of the choke cracked either before PCB assembly or during reflow soldering, either the thermal stress of cooling taking advantage of an otherwise survivable manufacturing defect or simply that the choke ended up in a position which stressed it once the solder cooled down (I've heard of it being a relatively rare failure mode with SMT, never seen an example with my own eyes (well, now I have seen a video of it)). Pro and hobbyist electronics geeks, take note :)
That ferrite bead is right next to the case screw spacer. Did the other half of the case put pressure on the ferrite and crack it when the screw was tightened??
in joe.smith video it is indicated that just above the failed coil L2/L3 there is a cut in the front cover (made by hand). Could it be that the coil was physically torn from its place because someone forgot to cut the pin in the front cover?
Did you report the issue with the faulty part to the manufacturer? QC feedback is very important. Hopefully, they will put additional testing or alternate suppliers into the production loop.
It appears to be a mechanical stress related failure than an electrical one.Or stress then fail.The cracked terminal on the inductor, If it is electrical would have taken out the surrounding trace. Vibration test would easily pick this type of fault at production. FMEA tools/techniques would be in order. Product returns are the manufacturers' and designers nightmare, especially so for low cost products. 3D CAD tools are a great help in this aspect.
Most likely the indutor got caught in the feeder in the P'n'p, and the lack of component in the end of production, made the operator reuse the old compunents in the component dump. If the inductor got caught in the lid of the feeder, the pneumatic action could easily have made a microcrack in the inductor. And the heat of the reflow oven, would make the crack expand. Add the vibration of transport and the heat changes, it will fail.
As it turns out, Dave has an ACL joint fault and the meter had a DC L joint fault.
No you didn't! :D
I'll pay that.
Thanks. That will be one thumb up, please.
Dave,
Have you moved to the new lab building?
Only a fool would ask that.
The more I watch of you, Big Clive, AvE and Fran, the more I learn... oh and I am 63 now and retired- you and your fellow TH-camrs are my Second University. Thank You.
All these repair videos that guys like Dave and Shahriar do make me wonder how many millions or billions of dollars worth of equipment ends up scrapped or junked or collecting dust because of the failures of single sub-penny components. I remember hearing so often that it wasn't worth fixing things, or people should just swap boards, but that seems so wasteful now. But I guess time is money, so that factors in.
Yeah, it's crazy. I was on Skype call with my best friend after my laptop's charging circuit died and they said something like "oh, about time to get a new one then". And I was shocked! Hell no, I'm going to rip this thing apart and see what's going wrong. Turns out a MOSFET was blown and I had a replacement part, and it only took an hour or so to get a new one in.
An hour of someone's time for component level repair is worth anything from $100 to $300. Older laptops or cheaper laptops would be easily totaled at that rate.
people throw out lcd monitors all the time because of 20 cent capacitors. back in the day you could find crt tvs and monitors on curbs for bad transistors, those only cost a buck or two a well.
First you pay someone to diagnose the problem (base pay + benefits + social security + Medicare + Federal Unemployment taxes + State Unemployment taxes + Workers Comp +++ etc.).
Then you pay someone to fix it (see above). Assuming it can be fixed.
And at the end you have a used piece of equipment that YOU have to warranty for when the next item fails (because the owner will never believe you did not break the component on a completely different board/area while working on it). Economics do not really support the effort UNLESS you are a small company (or single individual) doing the work. Or you can charge a lot for the work, such as repairing really high-end or rare pieces of equipment.
Sad statement on economics. Taxed to purgatory then further litigated into oblivion.
***** I would honestly be shocked if you charged me $10-$20 an hour to repair a modern laptop, but to each his own I suppose.
Mass production has a percentage of return rate due to faulty parts. The first one is pretty good after thousands.
Maybe put a signature on it and sell it as a refurbished limited edition one? :P
Great video ;)
That's a good idea, he could auction it as a prize or something ... I'm sure someone out of 350k people would be interested in having a genuine, as-seen-on-youtube, fixed-by-dave item!
Personally repaired by Dave? That is not refurbished, that is "made perfect..." or "quality assurance by Dave's own hands." It's like those flags that have "flown over the White House", they run them up, count to ten, take them down and bag them up. Market as "Used by Dave himself." or "Checked for accuracy..." or "Tested by Dave himself." It should be worth at least a 2X premium. 3:-)
I've torn and had surgery on my right leg's acl before. For Dave to diag this gents returned multimeter, on video, takes a maximum amount of character. good on ya Dave. Get well soon.
How'd it go?
+EEVblog I was young and I didn't stick to the pt properly. No pain but no full extension. I'm missing probably 3-8 degrees to full extension of the knee.
I thought that about Dave repairing the item on film. But then in most situations a sane person within this industry accepts sods law, like Dave admitted. It's just the way it is. It's also interesting to observe those who will not take responsibility or criticism and see it as a sign of weakness or what have you and do what they can to shun similar. Some people are glass half empty and some are glass half full with life's choices.
That would do it, yet, the physical therapy is very important.
Opened up my one while watching this - all the soldering is absolutely perfect including L3. I noticed L3 is right next to an alignment pillar on the case and there is a larger pillar on the back cover that goes over it which would put it right over L3. It could be possible that a compressive force on the case in that corner could push that onto the component and break it...? Regardless - I love the meter and recommend it!
I was thinking that also, based on that pillar and the isolation gap, there could be more torque on those components than expected.
I suggest taking another look at the other inductor, it looked to me like it might be cracked also.
Interesting observation, I'll take a look at that.
See Joe Smith review of the BM 235. He found the factory fix.
It is around 7:40 in that video.
You are right. See the 7:09 mark:
th-cam.com/video/g3uYcHAumhA/w-d-xo.html
Got my 235 the other day, 8 days from order on the web to delivery in Virginia, U.S.A. Wow! Thanks Dave!!!
Always amazes me just how many "electronic" faults turn out to be mechanical in nature!
I have little ideas about how that tiny world of chips work. But I find this stuff fascinating and enjoyed watching this teardown and troubleshooting. Good find and repair.
I just bought the EEVBlog-branded BM235 (off Amazon, since I am in the US) and it arrived this afternoon. Seems high quality and works great so far!
Love your integrity Dave, show it all good or bad.
I went over a bryman, not same model.m it also had weird intermittent issues as well. Repair shop never figured it out either. The distributor needed refunding my friend. It happens once in a while.
Sorry about the ACL, I had that surgery. Had bad after affects during recover. Not the worst surgery but not the most pleasant. My shoulder was worse in pain but faster recovery. Wish you luck with that surgery.
But did you knee eventually fully recover enough to play sport etc?
+EEVblog I'd say yes considering my situation. ACL and Meniscus are the common sort knee injuries. But being Type 1 diabetic w/ compromised immune system slowed down recovery. Just started rehab later then expected from swelling taking longer to go down, but once it did it was full speed ahead. Unfortunate I also had torn the Meniscus and because I had to fight insurance for two years for surgery approval it became beyond repair. So that bothers me, but ACL is good. I have a knee replacement approved, but don't want that until I feel it's the last option.
Key things are get it done as soon as possible, use a good sport surgeon that has done many of them.Don't slack off on rehab! My shoulder recovered better then original, but I was rigorous with rehabilitation. Everyone will tell you take rehab serious to build it back up and it should be fine, I know people that were lazy with rehab and years later regret it. Good luck, I'm sure you won't slack off with rehab and should be fine.
Is the small board with the input jacks well supported on the back by the case? It looks as if the red connector wire near the ground jack, that has no relief bend in it, could pull on the main board a little every time something is plugged into the common jack. The connection of the wire on the main board is right besides the inductor and the relief cut under the inductor will make any stresses to the board there go right through the inductor. This really looks like a design oversight.
Good point.
agree, that failed inductor is pretty darn close to the input jack...physical stress might be a contributing factor.
Maybe a moisture problem? Could crack the housing during soldering but keep contact so it would pass the tests (and as far as I remember it even cracked on the bottom side, so no real clue for visual tests either). Because of the reduced stability it is however no longer really vibration resistant (didn't look like it was glued down) so shipping could have broken the part in the end.
Great video Dave. I find the way you verbally annotate your thought process to be very informative. I look forward to seeing more repair videos in the future.. Thumbs up!
Solder joint on L2 looks cracked also Dave... Wonder if there's a bit of flexing been going on across the isolation gaps there underneath L2 & L3?
I think those pads look awfully big for those components, when you make solder strech this far, it's prone to crack under mechanical tension. Solder ain't flexible.
Do you always get this lucky with easily identifiable problems? Almost every time I open something up I'm hoping it will be just a quick simple component replacement, but it usually isn't lol
You're not alone!
lol even though I have almost zero electronics skill compared to this guy, I always hope the same thing. Hoping for some leaking caps, brown spots etc.
Look back on the channel about a year or so, and you'll see Dave's all-but given up on repairs because these days it's always something complicated.
I have a repair shop for mostly SMD components, and it's 90% cracked solder joints or component solder joints just like this. My microscope is my friend. Then mechanical parts like pots, switches, then transistors.
In case of such warranty claims right after using the product for the first time, it's very often a faulty component or some mechanical problem that happened during the production (bad connection or even a connector that lies around). The things will be different if one fixes only things that worked fine until now.
Next on sale: Multimeter fixed by Dave himself...
It's a jiggled model
I guess the componen was already slightly cracked or weakened during production or soldering but still held together well enough to pass testing without problems.
Then when it was shipped, it was in the cargo room of an airplane at high altitude, so it got really cold, I think up to -50°C or something at travel altitude? So in cold temperatures, things contract and in heat they expand. The component, when it was soldered, expanded slightly and when the solder colled down, it was held in place in this expanded state. At room temperature, there already was stress on the weakened component and when it was cooled down to the flight temperatures, the contraction force was great enough to finally rip the weakened component in half
Airplane cargo holds don't get down to -50°C. They have a single pressure vessel that contains crew, passenger and cargo areas. The whole vessel is pressurized, and therefore receives conditioned air. In some planes, the under-floor cargo area is sealed for fire protection and has its temperature loosely controlled by a surrounding air jacket, but none are open to external atmosphere.
Yep, more likely cooked in the back of a tractor-trailer or truck instead while being shipped.
Yep, I once had to leave a trailer full of Post Raisin Bran at the rest area in the Virgin River Gorge for a week while waiting on a part. 100 degrees + every day. Don't know how hot it got inside that trailer sitting in the parking lot.
Thumbs up how you handled that return and investigated the problem.
Sorry to hear about your knee. I'm fighting with my knee as well after a long bike ride, the bloody thing hurts like hell still after 2 weeks. Hope you will get well soon. :)
Nothing is perfect. That is a very low failure rate. Strange how that inductor broke off like that. I wonder if there was pressure on the area where the inductor broke, or high voltage blew it.
the movs would have saved it before it could think about its family
And that is how we do that Houston, nice work...
Just goes to show shit does in fact happen. Nice work Dave. I love it when a plan comes together!
I agree Dave,one out of a thou,send him a new one,no problem. Once you mess up a knee you usually end up with a life time of problems no more pro football for you guy! stick it in the freezer and see if it works,or heat it up in the oven. I got a RC Trawler that the electronics were dipped in of all things bees wax,try and heat that to check the solder connection.Its all through hole stuff. I tried penetrating the wax to test and ended up with a sticky mess. The boat is considered a collectable now,it was manufactured in Germany. I read up on these and apparently they leak and it shorts out the circuit board reguardless of the wax. I see a fireboat offered simular to these,not the same country of origin. I decided to move it up to the new age and chopped out that old technology and am updating it to all modern RC equipment under the hood. It shouldnt affect the collectability,if anything it increases the reliability and makes it more of a Hobby grade RC boat instead of a toy.
Now that's what you call a Braindump :-)
Thanks for the little lesson in trouble-seeking, Dave!
Good troubleshooting Dave! Get well soon!
you voilated your motto and turned it on before taking it apart!
interesting points ,if anyone else needs to find out about
repair board
try Saankramer Electronic Magazine System (do a google search ) ? Ive heard some extraordinary things about it and my mate got excellent results with it.
4 years later, still waiting for a reply from the eevblog shop support for my bm235 purchased from there, that has been dead since 6 months after purchase.
This Multimeter is going to be one in a kind because Dave took patience to fix it.
Sorry to hear about your injury. I hope you're on the mend soon.
I used to work in physical therapy. I saw so many people go down hill after knee surgery (as well as athletes). Please skip the surgery if you can or work really hard to get back on your feet asap.
That's not a good advice. If surgery is necessary he needs to take it. No offence, but you're not a doctor and ACL can have complications if not treated right. It's just about the stupidest advice you can give.
aserta Im saying skip the surgery if thats an option. as in the doctor says "get surgery of do these exercises for n months." So many people (americans at least) jump to surgery and don't even ask if there is a plan B.
You can get by fine without ACL surgery if you live a fairly sedentary lifestyle, and maybe just run or cycle for exercise or something. But anything else requiring any sort of twisting action will be out the question. eg. playing with kids, outdoor stuff, etc.
I did this injury 7 month ago, and I've popped my knee even in the kitchen just pivoting around.
I'm speaking to the surgeon tomorrow. But I already know it's entirely optional. I could win the tour de france or an ultra marathon with no ACL. But play ball with my kids in the backyard, probably not very well.
good luck with it then :)
Awww Dave! Sorry about your ACL buddy! I had to go through surgery and rehab last year for that. Keep up the great videos though!
I'm sorry to her about your knee, good luck with your surgery.
$22.75, the world's most expensive RF SMD inductor...
Enjoyed that very much. It certainly adds value to your product , because of your honesty. If I did not already have several multi meters, I would be tempted to buy one of yours. :-)
I have seen that happen with stale and mishandled parts, where the tinning on the part has oxydized before we got it in to the SMT pick and place.
Oxydized solders will cause localised heating.
Did I hear Dave say "let's turn it on"? Had to check twice that I watched the right channel!
That was interesting. I'd love to see a video of you discussing board layout, e.g. why star pattern ground is good.
I hope you get better soon, Dave.
Thanks Dave. I enjoy the repair videos.
Daaamn, ACL injuries are the worst! I did mine around a year ago now, had it reconstructed and I still haven't recovered fully. :(
Damn, a year, that's not good.
It's a case by case (injury degrees), how determined you are, mentally, and how good the doctor is with his/her pointy bit.
Tore the ACL on my left, twisted (never really understood what that term meant, getting the feeling it was medical slang) on the other leg, chipped my knee caps (legs went backwards) and after i had both legs on lock because of fluid, it took me 7 months to get in a functional state after the surgery.
By functional i mean i was able to run with some discomfort and in the winter knees (to this day) get colder than the rest of my body. Now, i was a kid back then, so, your mileage may vary.
I would alleviate pain with warm water compresses or hot baths, about a year's worth after.
Either way, try and find a good doctor (not sure how Australian system works), and follow their instructions.
Oh and, be light on your feet, you can get your other leg injured by trying to manage the other. It's really stupid and sometimes it happens, my doc told me it happens quite often, so, if you have to suffer crutches, suffer them, soft or hard bracing depending on how severe it is.
Yes, I'd be looking to get a top class ACL sports specialist surgeon.
Sorry to hear about your injury Dave, wishing you a speedy recovery man !
I snapped my ACL about 6 years ago while skiing in Switzerland, luckily not much pain but a load of swelling. Got back to UK and had it repaired on NHS (hamstring graft for those following the technical side) and I ski on it hard and fast ever since. Sometimes I can feel it but mostly good.
There is a new procedure I saw this month - www.themichelicenter.com/revolutionizing-the-acl-surgery/
Hope you (and Dave) heal soon.
Is it just me or dies the retest is an a different unit. The original had a blue case and retest has come back in black. Why is that?
Nice work. Emphasises the importance of a good visual inspection tool, such as a microscope.
Hey Dave, hope you feel better soon.
-A fellow Dave
Dave said he's sold over 1000 of these meters, I'm really surprised at that! I should be able to afford one next month!
Thanks for sharing! I have a older digital meter with similar issues, may use your TS steps.
Funny how biased and apologetic Dave is with different meters when you compare something like that with his reviews of UNI-Ts
That is true but I am still pleased that he is not afraid to go public with these issues. He could pretend there is nothing to see here folks.
I think criticizing Uni-Ts is fair, but maybe not for the reasons Dave does.
Yeah it is more likely the lack of strain relief on the wire connection next to the inductor.
@@SoftBreadSoft It shouldn't need strain relief. It's going from one board to another with both boards hard mounted to the same chassis. There's no strain on the wire.
@@MrPaddy1000111 If it's bent, it's straining. But yeah, could just actually be a bad part.
I've seen similar in amplifier boards. When the right tune is played the board gets into resonance and the joints or the surface mounted parts break.
With a gap underneath it's even more likely that this part will break.
With a daughter board only supported on the edges makes it more likely things like that happen.
You'd never get this problem with a UNI-T or a chinese firecracker multimeter! ;)
I have a UNI-T, which I'm quite happy with for the budget I had at the time, but there's no rear guard input safety protection to speak of (I think as I recall Dave's already done a teardown of that machine?) - This BM235 looks a really beefy chap in Comparison, no wonder it's reflected in the Price Tag (comparatively speaking).
Nice troubleshooting Dave. I bet the pick and place went pick and smash.
Agree
I think this might have happened at the assembly after all. Board was automatically calibrated and then put in the case. Components on the corners of the board or next to similar spots (cutout for the input jack in this case) sometimes get mechanical stress applied because something (or someone ;) )goes wrong and pushes on them during an assembly step. I work in an electronics plant, we get such failures from time to time when testing the assembled product. The components are usually ripped right off, leaving only the ends soldered to the pads just like it was on this unit.
Well done Dave
No luck with the ACL injury, Dave.
Hope you have a speedy recovery.
Yes this happens. I found one 0805 resistor with the same problem (was a Panasonic resistor) But was just one of over then thousand resistors of that model I used.
As a normal person not an old movie nerd, I had to look up the mass turbulence thing, I can see now why Dave would get irrationally upset of a reboot of an inconsequential movie.
Troll alert! inconsequential...
EEVblog Not really, maybe inconsequential is a bit harsh though. I am only expressing an opinion, I personally can't see what the fuss is about, I don't really do obsessive.
I'm sure it was just a fluke. I need to get myself one of these. Keep up with the great videos as always!
I spotted it before you did!!!!
Pick&place machine could crack that ferrite bead.
given the "apparent" rarity of a necessary inspection and repair of this, it's practically a bonus to have the man himself fix it, especially with the branding printed on it. Did you autograph it with a "repaired by" sticker or anything?
"You can pick these up from eBay cheap"... yeah 35€+25€ shipping... :P
It is cheap for the quality. I can't even find a 0.1% capacitor on Digikey. Best is one 0.5% capacitor and not in stock.
K71-7 0,5% is a cheap and common on ebay. SSG and SGM (0,3% hermetic mica) are not rare also.
Well, even 0.3% is not as good as 0.1% :-) Looks like it is really difficult to get very accurate capacitors. I could only find some from metrologic companies, but these costs 1k USD and more (but of course, they are even more accurate and with certificate etc.).
You can't flip it over. The actual trace that comes from inside, is tried to the cap end. So in this case, it's gonsky.
Also, it was mechanical stress. It went in hot, so the piece was hot and expanded, and when it cooled, it cracked. I've seen this once before almost identical failure.
My BM235 has the same problem. Mine has been working fine for a number of years then one day started doing strange things exactly as Dave explaned and I found the same L3 has come off the solder pad.
What are the holes in the PCB under the inductors for? It looks like the PCB may have flexed at that point.
Great eagle eye Dave !! That component issue could have been easily overlooked !!
At 6 minutes I was already screaming at the screen for you to open the damn thing and stop messing around.
Hi all!
I have a question specifically for Dave at the EEVBLOG. I have purchased a BM235 branded eevblog from amazon here in the UK under a year ago. I seem to have an issue with it at the moment where the meter seems to not give correct voltage measurement readings in normal V (DC) mode. The unit in this same V auto mode, throws a wobbly when I press the range button 3 times. Briefly I can see 'insersion error' and acts as if I have wrong probes inserted even if I have no probes! It does however show voltage readings for DC correctly using low impedance mode. Also, continuity mode without probes and with, displays a short. I have made a video and will upload it at some point today. I have seen similar issues with the dial which was posted a while back. Nothing I know has happened to the meter to cause this issue. I will post on the forum also soon.
12:17 good spotting there!
Very interesting! Thanks for sharing!
Hi Dave, i'm a great fan of your videos (and your great knowledge). But i think you're wrong on one issue here: the component placement print. Yes, it is good, old fashioned silk screen! no dot matrix here. The pattern you can see in the microscope is the nylon screen used for printing. All silk screen prints shows this pattern if you enlarge them. It's not half-tone screen like in a printed photo. (It is possible to print halftone images with silk screen, with half tone raster (screen), in this case the rule of thumb is that the halftone image should have half the lines of the silk. i.e. a silk (nylon that is) with 100 threads/inch, wil print an image with 50 lines/inch. Quite a coarse quality, as seen on t-shirts.
It looks like where L2 and L3 are on the board with the separation slots cutout, only leaves a couple of millimeters of board left, assuming that the boards are tested before being assembled into the case it wouldn't take much pressure to flex the board causing this damage if the assembler wasn't careful, just an observation, I don't have access to the board to confirm this possibility though.
ACL issues are nasty stuff. Get well soon, Dave! :)
Get well soon mate!
Сделайте пожалуйста на этот обзор , с разборкой - Brymen BM869s . Как это у вас называется - REPAIR ? Правда я ничерта не понимаю что вы говорите , но все равно интересно вас смотреть )
Looks more like physical impact damage to me - the component is sheared at one end and torn off the solder at the other - at 15:30 you can see the solder fillet appears to have been bent slightly down on the left side, also consistent with the component twisting off the pad.
This could have happened between bed-of-nails test of the populated boards and assembly into the housing. The manufacturer will know the exact sequence.
The damaged part is nearest the edge of the board - first to take an impact - those black plastic parts are part of the case? and were not able to protect the naked PCB.
It could have also occurred when the current shunt or red wire were fitted - slip of a soldering iron - looking at the solder in the vias I assume manual assembly of those parts.
Interesting. I'm always amazed that things like this don't happen all the time, there are so many components to fail.
Maybe it was cracked because of too much down pressure on the pick and place tool?
In that case I think it's more likely it had a weakness to begin with.
I think you broke it by taking it of. Inductors are often very fragile.
Sometimes the Parts stand up very slightly, especially Inductors. Its kind of a tombstone but the part stays on the solder and can still have contact. We call them "Auflieger", which translates into something like "lays-on", because they still lay on the PCB.
Get well, Dave!)
I ordered a BM235 from tme.eu, seems to have the same fault and has arrived DOA. Kind of put off the multimeter a little now after seeing this video before mine even arrived :).
Oh sweet I really want a EEVBlog multimeter now I might see it on here being repaired.
Although like ya said most likely a one off which I hope as well. :)
With the crazy number of components in modern devices its amazing to me that this kind of thing isn't way more common. When you think about it the percentage failure is actually low.
But we dont know how much didnt passed at fab.
It could be 50 failed for 1000 pcs.
Arek R. I don't really mean just this device. I'm thinking more any given device has hundreds if not thousands of components with that many points of failure if not multiple ones for each component. Then think of how many devices you have in your daily life. Its amazing that stuff isn't exploding left and right.
Think of computer motherboards, or ever server boards like that 8 PCI-E slot one on LinusTechTips. There's some ridiculous number of components with miniscule pin pitch and several layers in the board.
But then also think about the cheap Chinese crap that just about works through its usable life and is planned to be obsolete.
Computer/server mobos have up to 16 layers PCBs...
My $.02 guess is that the ferrite of the choke cracked either before PCB assembly or during reflow soldering, either the thermal stress of cooling taking advantage of an otherwise survivable manufacturing defect or simply that the choke ended up in a position which stressed it once the solder cooled down (I've heard of it being a relatively rare failure mode with SMT, never seen an example with my own eyes (well, now I have seen a video of it)).
Pro and hobbyist electronics geeks, take note :)
My money would be on a thermal stress failure during soldering.
So, if we get a dud, we get a troubleshoot and repair video for the dud? Worth more then the price!
Your voice is normal for an Aussie. ;)
That ferrite bead is right next to the case screw spacer. Did the other half of the case put pressure on the ferrite and crack it when the screw was tightened??
Joley good show man , you rock.
Surely these are tested in the factory where they are made.
How did the unit get passed by QC ?
amazing find
That was very cool.
Inductor could have been overheated during soldering, IE: the fault was it couldn't handle the heat.
in joe.smith video it is indicated that just above the failed coil L2/L3 there is a cut in the front cover (made by hand). Could it be that the coil was physically torn from its place because someone forgot to cut the pin in the front cover?
Did you report the issue with the faulty part to the manufacturer? QC feedback is very important. Hopefully, they will put additional testing or alternate suppliers into the production loop.
1-2% of failure is far a way acceptable nowadays. He just unlucky prehaps :) But we get an excellent video on repair :)
Sorry to hear about the injuries Dave! Hope you have a very speedy recovery and do not have to have surgery.
It appears to be a mechanical stress related failure than an electrical one.Or stress then fail.The cracked terminal on the inductor, If it is electrical would have taken out the surrounding trace. Vibration test would easily pick this type of fault at production. FMEA tools/techniques would be in order. Product returns are the manufacturers' and designers nightmare, especially so for low cost products. 3D CAD tools are a great help in this aspect.
Moisture contamination? Just blew when it was soldered (made good enough contact for calibration)?
I see a solder bridge (10:15) on the BTC chip (with the white dot on it) pin 36 to 40 but that must be just white color from under the chip.
I noticed that too but I think that if they where bridged that bad the whole unit wouldn't function itself
I don't see it ? between which pins ?
On the bottom of the upper chip I believe. Its only looks like a white marking on the side of the bottom edge of the chip.
i got one for Christmas,, and i love it. got shafted with customs but hey ho
Thermal shock in shipping, maybe? If it's sitting in a plane for a trip over the ocean, it's real cold for quite some hours, and then heats up fast.
Most likely the indutor got caught in the feeder in the P'n'p, and the lack of component in the end of production, made the operator reuse the old compunents in the component dump. If the inductor got caught in the lid of the feeder, the pneumatic action could easily have made a microcrack in the inductor. And the heat of the reflow oven, would make the crack expand.
Add the vibration of transport and the heat changes, it will fail.