EEVblog #1091 - LED Studio Light Repair - Page 1
Forum section: electronics / general

author: EEVblog
author_rank: Unknown
timestamp: June 03, 2018, 01:06:26 am
content: Dave discovers a potential systemic manufacturing issue with Lifud LED light drivers.A repair of two of Dave's failed Lifud LED studio panel light drivers.

author: IanB
author_rank: Super Contributor
timestamp: June 03, 2018, 01:34:58 am
content: A triumph of legislation over science.People spent years figuring out the best solder formulation and by experimentation they discovered that it was a tin/lead alloy. Then legislators came along and said "Nope. Science is wrong. You can't use what works best."Manufacturers, of course, were overjoyed. They had spent ages figuring out how to make things fail just outside the warranty period and now the lawmakers had required them to make things that fail early by law. More things get thrown away, more replacements get purchased, manufacturers benefit, and lawmakers get to feel all pious about saving the planet

author: VK3DRB
author_rank: Super Contributor
timestamp: June 03, 2018, 03:41:27 am
content: Good video Dave - I enjoyed it. In the old colour TV days, dry joints were perhaps the most common failures, especially where intermittent faults occurred. Tapping with the back of a screw driver could usually help narrow down there the dry joint was. Another trick was using heat and freeze to exacerbate an intermittent problem from a cracked joint. In this case, using cardboard shields could quite often narrow it down to a few joints.One thing I noticed was these LED drivers had no RCM mark. This means they cannot be imported and sold in Australia.

author: chickenHeadKnob
author_rank: Super Contributor
timestamp: June 03, 2018, 05:26:55 am
content: Quote from: VK3DRB on June 03, 2018, 03:41:27 amThis. Not just in the olden days of through hole though. Maybe I have been lucky with respect to electrolytic caps and unlucky with inductors, but the number of repairs of consumer goods involving either one has been roughly 60/40 with cold joints on pc mount transformers dominating. Two different brands of microwave oven went intermittent crapski after 10+ years in service with power supply inductor joints for example. Dave missed an opportunity to show how judicious and delicate board flexing under bias can quickly isolate the problem.

author: BravoV
author_rank: Super Contributor
timestamp: June 03, 2018, 06:40:03 am
content: Moral story, when it comes to dead end when trouble shooting a problematic ROHS soldered circuit, last resort, try re-solder all joints.

author: G7PSK
author_rank: Super Contributor
timestamp: June 03, 2018, 09:07:01 am
content: When it is just a small board like that the easiest thing to do is just re do all the through hole joints, it's quicker than looking for them in many cases.

author: Brumby
author_rank: Unknown
timestamp: June 03, 2018, 01:35:29 pm
content: Quote from: G7PSK on June 03, 2018, 09:07:01 amI've done that before.Sometimes it even works.

author: EEVblog
author_rank: Unknown
timestamp: June 03, 2018, 02:23:20 pm
content: Quote from: chickenHeadKnob on June 03, 2018, 05:26:55 amErr, I'm not going to go show people how to flex a live mains PCB.I've also use that technique where itdoesn'tisolate the problem.

author: EEVblog
author_rank: Unknown
timestamp: June 03, 2018, 02:26:03 pm
content: Quote from: VK3DRB on June 03, 2018, 03:41:27 amYes, I'm sure I've done that before in a video or two.

author: SilverSolder
author_rank: Super Contributor
timestamp: June 04, 2018, 01:15:33 am
content: Quote from: IanB on June 03, 2018, 01:34:58 amLead free solder... yuk. This stuff is definitely not as good as "proper" solder.

author: Fungus
author_rank: Super Contributor
timestamp: June 04, 2018, 06:27:45 am
content: Quote from: IanB on June 03, 2018, 01:34:58 amNope. We simply can't dump lead into the environment in the quantities used by consumer electronics.It's bad, mmmmkay?

author: james_s
author_rank: Super Contributor
timestamp: June 04, 2018, 07:12:04 am
content: Quote from: Fungus on June 04, 2018, 06:27:45 amSo don't dump it into the environment, recycle it. And with longer lasting gear, there is less of it being junked in the first place.

author: Kjelt
author_rank: Super Contributor
timestamp: June 04, 2018, 07:48:03 am
content: that, educate people no longer to buy the <$1 products and make the manufacturer/seller responsible for environmentally safe disposure.They make the profit, they should clean it up.

author: ejeffrey
author_rank: Super Contributor
timestamp: June 05, 2018, 05:24:18 am
content: Sure. The manufacturers would hate that, consumers would hate that, and even in the best possible implementation a large fraction of electronics waste won't get recycled properly. Oh, and if you are actually serious about it (rather than using it as a fig leaf for "I want to keep using leaded solder and not worry about it) it is absolutely the most hobbyist / small shop / kickstarter unfriendly practice you could imagine, since basically all of those things would have to be heavily restricted until you showed you had the ability to guarantee recycling and safe disposal of your products for decades to come.I don't mind people complaining about lead free solder. It is definitely harder to use and more prone to problems than leaded solder. That is established fact. But it also comes with real, documented scientific downsides. To say it is "legislation winning over science" is completely missing the point, and is actually anti-science since it ignores science which is inconvenient. Engineering (and law) are almost never about "A is good, B is bad", but the trade-offs between them.

author: IanB
author_rank: Super Contributor
timestamp: June 05, 2018, 06:13:00 am
content: Quote from: ejeffrey on June 05, 2018, 05:24:18 amI assume you are saying that leaded solder has scientific downsides, rather than lead free as your words seem to indicate? (Because undoubtedly, lead free solder has scientific downsides.)However, I would like to see some evidence that lead in solder is an environmental hazard. That evidence is absent from anything I have managed to find and read. Firstly, the amount of lead is small, and it is chemically inactive. In a chemistry class, have you tried dissolving lead? It is one of the most chemically resistant metals around. Secondly, electronic waste is rarely mixed in with general waste. It normally goes to special collections for recycling. Thirdly, when general waste goes to landfills it is carefully sealed due to the large variety of potential toxins it may contain. So it's not likely that water leaching from landfills is going to get into the drinking water supply or food chain.

author: Fungus
author_rank: Super Contributor
timestamp: June 05, 2018, 11:26:06 am
content: Quote from: IanB on June 05, 2018, 06:13:00 amWould you like an electronics dump near your drinking supply?At an industrial level: Lead-free works well enough (leaded solder goods used to have dry joints, too!)At a hobby level: Nobody's forcing you to use it so where's the problem?

author: orion242
author_rank: Unknown
timestamp: June 05, 2018, 12:24:00 pm
content: Quote from: Fungus on June 05, 2018, 11:26:06 amNear it, hell there are still a lot of lead pipes delivering said water.

author: Fungus
author_rank: Super Contributor
timestamp: June 05, 2018, 12:51:00 pm
content: Quote from: orion242 on June 05, 2018, 12:24:00 pmSure, but they'll have a nice protective patina on the inside now so there's not much point in replacing them.Would you be happy if they ripped out all those old lead pipes and replaced them with some fresh ones?Maybe we should follow the example of ancient Rome:https://www.google.com/search?q=roman+empire+lead+poisoning

author: orion242
author_rank: Unknown
timestamp: June 05, 2018, 01:25:21 pm
content: Quote from: Fungus on June 05, 2018, 12:51:00 pmSo that lead buried in the ground is safe enough, but electronics buried in the ground in specially designed areas isn't. Would think there are more problematic chemicals than the lead to worry about.

author: Scottjd
author_rank: Frequent Contributor
timestamp: June 07, 2018, 02:45:50 pm
content: And so is the problem with lead free solder on boards that heat up, expand and contract over time. Lead solder has more of a flex with it. Lead free just breaks, so technically it could be a engineering issue with thermal, if they keep it a little cooler then maybe the PCB wouldn’t expand as much? I see more of these breaking in the future.I know their is different types of lead free solder and maybe another one has more ability to have that expansion give based on the other metals mixed. This solder on these units could be more of a tin based that cracks easier? I just fixed a LCD TV that had an intermittent on or off LCD issue. I was expecting the common failed electrolytic cap on the PSU or the inverter board. Nope, it was a cracked solder joint on thenlne TV, thenlther TV was cheap caps next to somempower resistors, so it didn’t fail from the cap leaking but the cal couldn’t take the heat.I see more and more things failing these days from lead free solder cracked joints, might be worth another video explaining the different types of lead free solder and how the different metal mixes might be better for one use VS another use?Just a thought.

author: analogo
author_rank: Regular Contributor
timestamp: June 07, 2018, 03:35:16 pm
content: Quote from: IanB on June 03, 2018, 01:34:58 amIt is a triumph of one science over another. Chemical engineering found the best formulation for a particular business; environmental studies found that it is a pollutant. Environment >> Business.Take for instance CFCs. With CFCs you can produce superb and cheap refrigerant fluids. That hasn't stop us from outlawing them for good reasons (the ozone hole).This is not that different from the various wireless scams out there. Technically they may work, but there are serious health considerations that will limit their power and, in the end, will prevent them from being deployed.

author: apis
author_rank: Super Contributor
timestamp: June 07, 2018, 05:05:12 pm
content: All that solder ends up in landfills and then it leaks out into the environment. There was lead, cadmium and other heavy metals in everything from paint to toys for a while so it was a good thing they began regulating it.Quote from: Scottjd on June 07, 2018, 02:45:50 pmThere are millions of lead free power supplies that work just fine.

author: Fungus
author_rank: Super Contributor
timestamp: June 07, 2018, 05:10:09 pm
content: Quote from: orion242 on June 05, 2018, 01:25:21 pmYou know how I can tell you've never googled "electronics dump"...?

author: orion242
author_rank: Unknown
timestamp: June 07, 2018, 05:45:05 pm
content: Quote from: Fungus on June 07, 2018, 05:10:09 pmPlenty of areas still dump sewage in the street. If the locals don't give a toss, its of little concern to me. How many of these exist in the US/EU etc?

author: apis
author_rank: Super Contributor
timestamp: June 07, 2018, 05:52:35 pm
content: Quote from: orion242 on June 07, 2018, 05:45:05 pmI bet those places allow led in their solder as well.

author: Fungus
author_rank: Super Contributor
timestamp: June 07, 2018, 05:55:00 pm
content: Quote from: orion242 on June 07, 2018, 05:45:05 pmNice attitude.Quote from: orion242 on June 07, 2018, 05:45:05 pma) How much of your US/EU electronic waste ends up in one of those places to be "recycled"?b) Planets with oceans are global things. What goes around, comes around.

author: orion242
author_rank: Unknown
timestamp: June 07, 2018, 06:15:55 pm
content: If the local government is stupid enough to take it and the locals just accept it, why should I get too excited about it? If we stop garbage, it will slave trafficking, if stop that it will just be the next human catastrophe, and the next. At some point the locals need to put their foot down, or they will continue to get walked on. If that fails, use your two feet and get out of there.Might be pretty blunt, but I'm not naive enough to think we are going to solve everyone's problem. At some point, the change needs to come from within.Again we still have drinking water delivered with lead pipes, we go to shooting ranges and pump the ground full of it. I don't think lead from electronics in a proper dump is of much concern in the grand scheme of things.Even in your "electronics dumps" lead probably isn't their biggest life quality issue or even in the top 10.

author: orion242
author_rank: Unknown
timestamp: June 07, 2018, 06:20:12 pm
content: Quote from: Fungus on June 07, 2018, 05:55:00 pmLol, I hear we are working on a wall for that.

author: apis
author_rank: Super Contributor
timestamp: June 07, 2018, 06:42:28 pm
content: Quote from: orion242 on June 07, 2018, 06:15:55 pmNot realising that all of the world is connected is naive if anything is.Quote from: orion242 on June 07, 2018, 06:15:55 pmAnd how is that working out for you?https://edition.cnn.com/2016/03/04/us/flint-water-crisis-fast-facts/index.html(maybe that doesn't concern you either?)In this part of the world we don't use lead pipes, and for hunting we use steel shots or other alternatives when possible. But lead based hunting ammunition is still an environmental problem that is being worked on.The reason lead was regulated is because there was lead ineverything, so eventually we had to "put our feet down" and limit lead use to where it is strictly necessary. Maybe you should "put your feet down" too.

author: orion242
author_rank: Unknown
timestamp: June 07, 2018, 07:39:51 pm
content: Quote from: apis on June 07, 2018, 06:42:28 pmExactly my point. Politicians tried to save a buck, more than one knew there could be issues, yet all turned their heads and approved it. People rose up and a handful of politicians got tossed on their a$$. All a sudden there is movement to replace the lead pipes that before would have sat there another 100yrs.https://sverigesradio.se/sida/artikel.aspx?programid=2054&artikel=4759979"A geological survey conducted in 2008 showed that one fifth of Sweden’s wells contained water unfit for drinking. Swedish Radio News reports that the situation has not improved since then.The source of the problem with poor quality well water may be that the ground contains dangerous elements like arsenic.The most common cause, however, is that sewage leaks into the well."Maybe your right, lead's not in your water its poop! Would be pretty surprised if they never used lead pipes at some point or that every inch has been removed there.

author: apis
author_rank: Super Contributor
timestamp: June 07, 2018, 08:31:51 pm
content: Quote from: orion242 on June 07, 2018, 07:39:51 pmGlad we agree lead should be regulated then.Quote from: orion242 on June 07, 2018, 07:39:51 pmWow, was a long time since I heard a poop joke! The wells are private, it's basically a courtesy notice telling people who has property in the countryside that they should check the quality of their water supply. Municipal water quality is very good here, although in some places the pipes are getting old and need to be replaced. Not sure what that has to do with anything though.More relevant is that the water in lakes and the Baltic is so full of environmental poisons that you can't export fish caught here to other countries. The national food agency recommends you don't eat lake caught fish more than once a year.http://www.spiegel.de/international/tons-of-mercury-found-in-the-baltic-sea-europe-s-underwater-chemical-dump-a-434329.htmlThat is what happens if you don't give a shit about the environment.

author: orion242
author_rank: Unknown
timestamp: June 07, 2018, 09:33:50 pm
content: Are there any studies showing a marked reduction of lead in drinking water due to ROHS? Surely this should have some measurable impact by now?Has anyone studied if there was a true reduction in waste or if switching just caused more frequent product failures thus more ewaste?Sounds like the Baltic states need to make like the peoples of Flint and hang a politician or two until you get what you want.

author: apis
author_rank: Super Contributor
timestamp: June 07, 2018, 11:18:12 pm
content: I think you are missing the point, we stopped dumping toxic waste in the Baltic a long time ago but we are still paying the price for the sins of our ancestors. A lot of it is from a 60-100 years ago when people apparently believed dumping things in the ocean was a great way to get rid of toxic waste. Thanks to them we now know it is quite possible to poison even an ocean if not careful.Of course there is research, here is one study from the USA:https://www.epa.gov/sites/production/files/2013-12/documents/lead_free_solder_lca_summary.pdfDo you really think the EU would begin regulating the use of lead without any scientific basis? People seem to think EU somehow targeted lead based solder to make the life of electrical engineers difficult.The RoHS directive simply tries to limit the use of some well known environmental toxins (among them lead, mercury and cadmium) which is a good thing. Unless lead is strictly necessary you should use alternatives, and in most cases lead free solders is a perfectly fine alternative. If you really need lead based solder you can get an exception. It's been a while now and we still use electronics in Europe, the world didn't end.

author: james_s
author_rank: Super Contributor
timestamp: June 08, 2018, 12:14:53 am
content: I'd still like to see some data. I support being environmentally conscious, but I think with reasonable steps taken to recycle electronics the amount of lead dumped into landfills can be minimized. That doesn't mean we have to be heavy handed and require ALL electronic waste to be handled by a certified recycler, but anyone handling tens of tons of the stuff should be given some scrutiny.On that note, I would like to see a different approach taken with e-waste recycling. The recycling locations should be set up so that stuff gets dropped off in a staging area where people are allowed or even encouraged to come and pick through it taking what they can use. By far the most efficient form of recycling is reuse, and everything that gets repaired and put back into service is one less item that gets scrapped. Scrap is the lowest form with the least value since you can't recycle the effort that goes into turning raw materials into finished products.

author: orion242
author_rank: Unknown
timestamp: June 08, 2018, 12:28:21 am
content: Quote from: apis on June 07, 2018, 11:18:12 pmThanks. Don't have the time tonight for a full read, but will this weekend.Quote from: apis on June 07, 2018, 11:18:12 pmNot at all. However they certainly made assumptions on what the final impact would be since they couldn't have actually measure the outcome before enacting. Its been 10yrs now. Has anyone verify it made any measurable difference in say lead levels in ground water? How much impact did it really have?We can measure the ozone hole since CFC bans. What does global lead contamination levels look like now and are they declining? How much can be attributed to ROHS? Or was this just something to make us all feel better without doing a thing to solve the real problem?

author: Fungus
author_rank: Super Contributor
timestamp: June 08, 2018, 09:51:46 am
content: Quote from: orion242 on June 08, 2018, 12:28:21 amWe can measure airborne lead after we stopped putting it into gasoline.FWIW: It coincides nicely with a massive drop in the crime rate.

author: Brumby
author_rank: Unknown
timestamp: June 08, 2018, 10:03:02 am
content: Quote from: orion242 on June 07, 2018, 09:33:50 pmI believe you are being far too unrealistic about your expectations. Reduction of levels would indicate existing contaminants being removed from the ecosystem - and that is clearly an extremely difficult exercise, with an unimaginable cost.I would limit my expectations to seeing a slowing of the increase - but even then you would have to consider things like previously discarded materials that were encapsulated in some way being released.IMO, it is going to take quite some time for any definitive results to show up, but if we don't start making serious efforts - wherever we are in the world - then we can't ever expect positive change.Being the first adopters might be lonely at the start, but will be seen as pioneers when the rest of the world starts catching up.

author: Fungus
author_rank: Super Contributor
timestamp: June 08, 2018, 10:46:08 am
content: Quote from: Brumby on June 08, 2018, 10:03:02 amYep, somebody has to step up and create standards.It doesn't take many people willing to make a buck atanyenvironmental cost to wreck the planet. Not these days.

author: IanB
author_rank: Super Contributor
timestamp: June 08, 2018, 02:27:32 pm
content: Quote from: orion242 on June 07, 2018, 09:33:50 pmThere was no lead in drinking water to begin with, so no reduction could be measured.

author: james_s
author_rank: Super Contributor
timestamp: June 08, 2018, 04:09:57 pm
content: Quote from: Fungus on June 08, 2018, 09:51:46 amThe lead added to gasoline was a large quantity, and it was vaporized all over the world landing on the surface. We are not grinding up millions of tons of electronics waste and spreading the dust all over the surface of the earth. It's quite a different thing.

author: orion242
author_rank: Unknown
timestamp: June 08, 2018, 05:38:29 pm
content: Quote from: IanB on June 08, 2018, 02:27:32 pmTell that to Flint, Chicago and countless other cities across the globe that still are drinking water though lead straws. Seems almost all the lead contamination in water supplies is due to plumbing lines, fittings and solder and there is little leaching concern. Fair enough.So if lead leaching in the ground is mainly a non-issue, where was the problem? You would think after a decade of near world wide ban, some measurable impact exists. If not, this seems to fall into the warm and fuzzy feeling legislation, not real problem solving.

author: apis
author_rank: Super Contributor
timestamp: June 09, 2018, 12:41:41 pm
content: Quote from: orion242 on June 07, 2018, 09:33:50 pmThe problem with doing such a study is that we have been trying to remove lead ineverythingfor a while now, not just solder, so determining exactly what effect switching to lead free solder has is hard. What you can measure are things like lead blood levels in children but it will be hard to tell exactly how much e.g. lead from solder contribute because there was also lead in paint, or plastic, etc. (We know lead levels in blood dropped significantly after we stopped using leaded gasoline at least.)Quote from: orion242 on June 08, 2018, 05:38:29 pmThe problem is that there is lead in places there shouldn't be any lead:https://en.wikipedia.org/wiki/Blood_lead_levelAnd lead in the environment is also definitely a problem.Quote from: orion242 on June 08, 2018, 05:38:29 pmIf you know there is a problem with lead poisoning of humans and the environment then it's sensible to try and limit the use of lead even if you can't tell exactly what is the main source.Even if you try to carefully recycle everything, some of it will end up in places it shouldn't (especially cheap mass produced consumer products). This is a way to get the situation more under control.