I believe it is systemic to lead free solder. I work on Motorola products, and that's 75% of the issues. Usually on connectors between boards, then SMD's or even flat pack legs. The rest of the issues are switches, chip/trans failures, pots, knobs and buttons roughly in that order. But, even so, in 1985 I worked on an old box of a 5 watt radio that was outputting less than a watt. I saw a bad solder joint, then just resoldered the whole board and bam, got all of the 5 watts back. That was 6 months into my first electronics job ever and the boss was amazed and I was somewhat proud of that fix.
The micro cracks strike again! My old truck had a faulty ABS module (over $1000+ to replace at the dealership!). After seeing lots of people claim its just faulty solder joints, i took the task to take it out, take it apart, and clean up the joints. Its a big pain since the unit is all sealed up with silicon, but the solder joint touch up did the job. Before the fix, every time i hit a bump, the abs light would come on. Just guessing the vibration + bad joint would cause the fault to trip. Who knows how many people were out $1000+ because of this.
Looks like cold solder joints from the higher melting temperature of pure tin is the most likely root cause, and a manufacturing process that didn't get it up to full flow temperature. Looks like these assemblies were hand soldered vs wave or reflow. ROHS is the dumbest idea spawned by politicians of the EU. And is having the opposite effect of more electronics thrown away prematurely. They didn't take into account the amount of toxic chemistry it takes to make integrated circuits, and the printed wiring boards. All they thought about was the lead being tossed into landfills. A better solution would have been a requirement to recycle all electronics. At least the industry I worked in (avionics) was able to get a waiver on pure tin solder. Mainly because of the tin whisker problem.
I don't think this has anything to do with lead free solder. This problem has been around since well before ROHS was even thought of. This is a typical problem with using cheap single sided, non plated through PCBs. I first saw the problem in portable CRT televisions donkeys years ago. The problem is always with heavier components (typically inductors/transformers) that are 2nd stage (hand inserted) just before the flow soldering process. As you will see in the video, the holes for these components are much larger that you would expect, for ease of component insertion, however this means that the only thing holding the component in is a very thin layer of solder between the lead of the component and the pad due to the reduced meniscus. Thermal cycling and vibration does the rest. If the PCB had PTH's then this wouldn't have been a problem!
Also, large heavy components such as coils, power transistors and caps should always be hand soldered. Wave soldering just doesn't apply enough solder to these because of the higher thermal mass.
I repaired similar thing in my LED power supply. Apart from cracked joins I had to add solder to main IC, because half of legs wasn't touched by wave at all. The satisfaction is always there, when you find that thing.
MEAN WELL LED Power Supplies!!! Go for them in future. Can't go wrong. I've had good results from all the Mean Well LED power supplies I've used. Many years in with some of them, all still going strong. Great build quality.
2:25 Dave, if you'd allow me an advice: I always solder the end of multi stranded wires before placing them into termination blocks. (1) You never have to worry about oxidation, (2) You need less torque on the bolt for the same result (less mechanical stress for plastic parts) (3) Once the bolt is tightened, it makes a dent on the wire, that provides an extra security for slipping out like what we've just seen. In my lab, all wall sockets, wall plugs, light switches, extension leads are mounted like that.
I reckon it’s the lead-free solder Dave. I repair a lot of audio gear and the newer stuff with lead-free solder often exhibits these types of faults. Older gear with leaded solder tends to last a lot longer before these sorts of faults appear.
Interestingly in the old days, in television horizontal stages and switchmode power supplies with high pulse currents, localised heating causes the tin in leaded solder to migrate to the outside, leaving a 'leady' high-resistance joint that eventually fails. Used to be the one of the first thing to check in a dead telly... :)
Lead-free solder is too brittle if a bit of thermal cycling between what, 18 degrees and 27, is enough to crack joints. Nice to hear you working the rabbit/herring connection.
17:00 "Is that because of this new fangled lead free rubbish" Yep, that is exactly the reason. Lead free solder is brittle and doesn't flow as well as leaded solder. Also their wave soldering is crap. Wave soldering never properly solders large high thermal mass components like power transistors and coils. Large components should always be hand soldered. Ive lost count of the number of single sided lead free wave soldered boards just like yours that ive repaired just by resoldering cracked joints. On some power supply boards in LCD TVs that I've repaired, ive resoldered every joint with leaded solder because the wave soldering just didn't apply enough solder.
@Simon Tay > Lead free solder is brittle and doesn't flow as well as leaded solder. Bullshit. If your solder is brittle, then you're using the cheapest China stuff. Modern top shelf lead-free solder has much better properties than the best leaded solder alloys that can be bought nowadays, since vendors stopped producing the above average leaded stuff due to massively dropped demand. > Also their wave soldering is crap. That! Could also have happened with leaded solder but it is much more forgiving to manufacturing problems like that.
I only use leaded solder. I mean the existing lead free solder on the board. It cracks because it is brittle and there not being enough used. Failure rate for lead free solder is definitely higher than leaded solder. Leaded solder doesn't crack as easily.
Thanks Dave, just had a defective Lifud LED panel light and PSU on the bench where all components measured good but it would still not power on nor generate anything near the specified 55VDC output. You gave me the clue I needed. Despite using a microscope, I could not find any broken joint but it's up and running now that I have redone just all of them. 🤞 I might have spent around the equivalent of 100 AU-$ on a new power supply, and discarded one where all except the soldering was in best shape, if it wasn't for you. Thank you so much! 👍
Gah, that's pretty rough. Potential for mass quantities of those getting borked in no time, and Dave might need to open up to fix them multiple times until most components have been resoldered.
If you suspect a solder joint problem try probing around with an insulated poker on the top components. It often won't take much to make or break the connection and find the faulty part. Then just re-solder all its leads.
Awesome footage. Dodgy solder joints can be quite troubling. I fixed a very old EZflash 3 in 1 by simply removing everything and putting everything back.
i get this flickering problem with a bunch of high bay 250w led fixtures. the problem is that they have poor design. using 12 36v cobs in 6s2p. when one or more led burns out the driver will start flickering the leds.
I think after the first couple of dodgy joints, I wouldn't have bothered looking for bad ones, I would have just run across all the through holes with proper leaded solder. Damn lead free crap, I swear it's the cause of 90% of failures.
Unless a proper stranded connector is used. In this case, the power supply used a really crappy spring clamp type connector, which is allowed for use with stranded connectors, its just not good at it. You are correct though, when only a screw is present, such as in electrical distribution boxes on the rails or some styles of breaker just use a screw, only solid wire can be used.
Same screw clamps in just about every breaker box that i've come across, designed to be used for solid copper. Maybe they're trying to accomodate solid AL wire with the springs too, but I'd at least try to tin anything stranded, even with leadfree solder, before trusting it under a clamp.
These connectors are fine with stranded wire as long as you don't twist it before you put it in. The issue is when you twist up the ends of the wire it has a larger diameter than if you leave the strands all straight. Eventually it can just fall right out, especially if the wire is bending coming right out of the connector into insulation bundling multiple wires together.
With the first cracked joint we can see that there was not much solder once you heated it, too thin and just cracks. That hole was too big, and because it's single sided PCB, without plated holes, it haven't got filled properly. Could be also because of oxidation on the components(stored for long time).
"u feel lucky....punk....." hahaha LOL! now i'm gonna have to go to my old vcr tapes and watch some of the dirty harry movies! i must have seen them 100 times, still love them!
As an FYI, If you're based in Australia, those led drivers are missing the RCM mark. Australia national deviation requires a higher glow wire test of 750C on the plastics, EU only require only 650C. Please be careful!
ferrules also look better. The flair can be a nuisance for closely spaced connectors but in this case would be ideal. IMO opinion it is the better way to terminate a connection.
uptherewhere Ferrules with flairs won't fit mechanically in the space between the cable clamp and the wire clamps. Simple ferrules might fit but are against manufacturer specifications as printed on the lid.
3:00 That tends to happen with stranded wires when they're twisted up and put into bare connectors, or even crimp connections. While it's easier to get them in there because the strands won't bend off as much when you're out of alignment, the issue is the twisted up wire end actually has a larger diameter than if the strands were all straight. Over time it can untwist, get stressed, etc. and then just fall right out!
Had a Sub in a vehicles stock audio system not working, or sometimes working intermittently. A board mounted next to and connecting to the sub was my first spot to check, and after removing it, found the same problem, a cracked joint on a relay. Though, mine was much smaller, but after a quick re-flow of it and a few others just to be safe, popped it back in and it worked, good as new.
lead-free solder is one of the worst things to happen to electronics and the environment as it increases the e-waste pile enormously :( . Should we therefore go back to leaded in commercial products? NO way. I'm more for a vivid repair mentality. Let any man and woman have the technical skills to unscrew the case, fix the issue and place it back. Force open availability of schematics and parts from the vendor at reasonable prices. DIY and right to repair is what would ultimately reduce the e-waste pile
Free standing (large mass) components soldered to a one sided PCB with no thru-hole vias using lead-free solder. Throw in some temperature cycling and heating on that nice big copper wire. I'm guessing that copper layer is pretty thin too. Yep. What could possibly go wrong? Good catch on the cold solder joints. I used to have to try and find those buggers without a microscope. Mind you my eyes were only 20 years old. Cheers, - Eddy
I have found that large lead parts need a couple of seconds more in the wave solder machine to prevent a cold solder joint. This was found in failed power supplies for gaming equipment at a manufacture i worked for several years ago,
For academic history preservation, you should duplicate all those decks to an off-continent similar museum along with photos of any written or printed labeling. Do the same for them.
Since the advent of lead-free solder, on anything like this, with only maybe 50 or 60 connections, if I suspect soldering issues I just reflow everything on the board with leaded solder. Takes maybe 5 to 10 minutes at most and problems solved. If I try to hunt for individual ones, I've wound up with something that works for another month or two, then I'm right back in there. Not only is the lead-free a problem, but I'm finding that on through-hole stuff they're too skimpy with the solder. They're barely maintaining the physical connection, and vibration easily causes cracks.
The reason for the flickering.. You said it was the active/live that had come lose from the terminal block. Well judging from the color then yeah your right. But i can guarantee you the receptacle on the other end of the cable isnt polarized. So the flicering would have been the because the live was feeding voltage into the caps and there is enough ground potential with the return so close to the terminal block. Its just caps charging up and dumping the power.
Fouzai alaa. Exactly. Houses in europe, Australia and the UK are made properly with solid thick brick walls with caverty insulation, not thin walls made of plywood and plasterboad with no insulation.
KeeDx3 Oi mate! Don’t argue with these fine gentlemen! It’s their right as Englishmen to bitch about how shit America is, an’ how great the homeland is! ...and don’t mention the BBC! I hear they go bonkers at the mere mention!
walls are made by 2x4 or 4x6 depending, im sure if you wanted you could make em thicker. I know id like a brick castle style house if i had the money though
Nice repair and nice find! You fixed both using only a soldering iron and a screwdriver 😛 It looked like the solder was originally about 0.05mm thick which pretty much wouldn’t survive a sneeze!
Davo, would you recommend soldering the copper on the ends of those mains wires to give the clamps more to squash down and overall conductor density? Once again, another good presentation... 10/10
Everyone hates on the solder but here I am sitting scratching my head. The SMPS has three input connections, the cord has three wires, but only the live lines are connected. Oh the ground/earth lead was just snipped off by the installer. Hmmm... Grounds are important for EMI controls, at the minimum. Also stacking those SMPS/LED drivers in a heap, is just asking for thermal problems. It's like sticking layers of heated blankets on. The one(s) directly on the panel are getting heated by the panel itself too. Mmm thermal sandwich fueling runaway temps. Cable and device management is a thing for a bunch of reasons. -_- I was seeing a few crackers, but he didn't show the other joints that he retouched. So its hard to say but there were a few that needed love on both. On the second one there's three pins in a triangle, Dave retouched two, but that third one was hinky. I'd bet the other good units have a bunch of joints on edge and should be inspected. Trends be trends.
Understood, just curious what the most likey yet still unlikely failure modes are besides overloading. They're typically temporary but it's something a lot of people do.
The comment thread starting with "EEEEKS" puts a finer point on it. A current path (dead short, some sort of contact resistance, etc.) will dissipate four times the energy at 220V versus 110V. While electrical codes vary, it seems setups like that (hidden in an enclosed space) would be even more risky with 220V.
Lead free solder sucks for copper plumbing too. The first time I used it about 10 years back it was some wonky Cu-Se-Bi mix. Took me 4 attempts to sweat a half-inch copper pipe on to a brass valve. Previously I'd had about a 1% failure rate with with 60/40 in. I've since changed solders, and keep my 60/40 for copper drain lines, where it is still legal here.
Right, who's issued the sense of humour removal pills? For a start, there's nothing wrong with not crimping or soldering wires that are being tightened into this type of clamp, most of the wiring already in the building is done with bits of solid core wire twisted together and shoved into connection blocks, so what's everyone whining about Dave's decent job for? And secondly, what's so bad about having an extension cord in the ceiling? It's the same as having a junction box for a ceiling rose up there and if they're fused they're probably safer than the junction box would be. Finally, if the electrical standards agency that certified the building after it was built don't want extension cords in the ceiling, why did they not kick up a fuss about the drop cords that are installed on a 15amp circuit with no built-in fusing? Some people need to get a dose of common sense I swear. Dave should make a video responding to these cancerous comments on his second channel.
I blame the lead-free solder. Craptacular rubbish. Get some delicious lead on there, Dave! Far as I know, only manufactured goods require it by law, not rework.
i just fixed an old novelty strobe light from 1971 (oct 26, according to the stamp on the PCB) and the 3 pins on the mount for the flash bulb were dangling in the breeze a bit. it might have taken a drop or 99 since the Beatles broke up... and also, the neon bulb that was in there (i believe as some sort of current limiter, not the same as the flash bulb) had to be put to pasture and replaced. one thing that i found interesting was that the neon bulb that i replaced it with arced a bit inside for about 2 or 3 seconds on it's maiden voyage... it was an EICO neon bulb from i presume /at least/ the 1950's, if that helps demystify the situation. also, i left all the old original caps, for now. the strobe light is working hunky dory so far and the neon bulb is orange-ly glowing happily - though, it's inside the enclosure and you can't really enjoy its warm orange glow. might have to install a mini wireless webcam focused right on it inside the enclosure just to enjoy it. nah, probably not... cheers.
Every country has its own ways to do electric installations. But at least in Finland, you are supposed to put crimped sleeves on stranded wire that is connected to a screw header, yes it has the metal between the screw and the wire but still, at least you should have tinned the ends, an installation like that of course would actually need solid core cables, since it's not movable, but I'm pretty sure you know that already.
Seems like the HASL surface finish of the PCB somehow did not match up well with the wave soldering? It seems like the tin on the pads did not melt all that well on large components and form a good joint... just made it out good enough to survive for a bit.
This is a serious problem. Solder cracks and cracks in vias due to thermal expansions and this happens due to the bad selection of PCB raw material and matching PCB soldering process. For example a TG150 rated PCB material is better than TG135. The higher the number, the lower the Z axis expansion. We went down the rabbit hole for months to find out this problem.
When I see a single slightly sketchy solder joint on a circuit board, I just reflow every joint on the board with leaded solder and fresh flux. Even if a joint is not broken now, it will be broken soon and you'll have to fix it again unless you improve them all at once.
On the cover 4mm lead length from outer insulation to stripped wires. By exceeding this yo are putting the cable outer insulation outside the clamp, or putting a stress on the leads as they 'S' bend between the end of th cable and the clamp.
Hi, Dave. Why didn't you solder AC cable ends or put a proper pins to go under screws? As far as I know cables like yours here should be soldered or used with proper pins. It is interesting what do you think on this?
I have some test equipment i made my self, the live goes threw a cheap rocker switch and the unit it self is very low power, when turned off the backlight on it flickers every couple of minutes due to capacitive coupling
Those leaf clamps...unscrew a way and push a small screwdriver in the hole to align the leaf, allows for easy entry and grippier connection - need 'priming'
I used to tin wire ends with solder until someone told me it wasn't safe, so I bought a six sided ferrule crimp tool and now whenever I'm wiring anything, I always use ferrules.
5:09... Another problem that I can see is the bare wire strands are not all parallel and twisted together to get a good grip by the Blue Connector clamp.
In old days we had similar problem with our color CRT TV and its remote would stop working and service guy came and just resoldered the joins to fix it. Later he got fed up and changed the whole TV under warranty. Throughout the video I could not digest that it would simply be a disconnected main wire to cause flicker.
Used to have solder joints go bad all the time on TV flyback transistors. Joints on components which thermally cycle a lot are worst, but there might be something with high peak currents too. Solution - use a plated-through board!
I once repaired a big kitchen mixer. The main choke broke off just before the solder joint. So it was in it's hole, looking all fine. No cracked solder or anything either. I found it by accident before I went to measuring the non obvious. How does that even happen...
Single sided PCB's with large pin/hole clearance for automatic placement of heavy component are prone to fail. Vibration and thermal stress will eventually lead to the results you have experienced. That was common knowledge when I started as a B.Sc.EE in 1978. Forgotten knowledge??? Regards from Denmark oakey
Maybe the shipping case was damaged in transit or dropped? That would be more likely considering these are from a relatively trusted manufacturer. All the cracked joints were on high-mass components, so I'd suspect blunt impact caused the initial damage; thermal cycling just finished the job.
You swapped AC_L and and AC_N connection on the screw terminals of the flick-one - no wonder it got loose ;) But where is the AC input filter cap? Is it just that 4,7µF one?
Dan Smith - not at all, Australia has the strictest wiring rules in the world. The wiring in that ceiling space is a dogs breakfast and indeed does not meet the AS3000 wiring rules. A bit more catenery wire and some zip ties would sort it, but obviously the Sparkies who work in this building don't give a shit - a whole different problem. NSW has little to no inspectors who could be asked to look at this after the fact though, In Victoria, a quick phone call to Energy Safe would have a compliance officer on site quick smart and a rectification notice issued.
Do R/C! It’s fine to do this in Australia and New Zealand (unified standards for most things). You need to have properly installed AC outlets up there, but otherwise this is safe enough. We have a WiFi router and other assorted IT stuff in our much shorter false ceiling space. The reason you go this way is to prevent unqualified people from deciding to save the cost of hiring a sparky, and poking around with permanent wiring. Much safer to have the usual AC outlets available for end-users to plug stuff into.
