What's with wall warts?
What's with wall warts? Do they have a five year warranty clock
built-in? I just lost the third wall wart in a month. All of them 5+ years old, or more, so I guess I can't complain. What's to wear out... capacitors? This one was for my Cisco BEFSR81 Router. I think it's actually a lot older than 5 years. I'm presently up and running on a bench supply :-} ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food. |
What's with wall warts?
Jim Thompson wrote:
What's with wall warts? Do they have a five year warranty clock built-in? I just lost the third wall wart in a month. All of them 5+ years old, or more, so I guess I can't complain. What's to wear out... capacitors? This one was for my Cisco BEFSR81 Router. I think it's actually a lot older than 5 years. I'm presently up and running on a bench supply :-} ...Jim Thompson Shouldn't be hard to find a replacement. -- Les Cargill |
What's with wall warts?
On Sat, 08 Dec 2012 13:45:02 -0600, Les Cargill
wrote: Jim Thompson wrote: What's with wall warts? Do they have a five year warranty clock built-in? I just lost the third wall wart in a month. All of them 5+ years old, or more, so I guess I can't complain. What's to wear out... capacitors? This one was for my Cisco BEFSR81 Router. I think it's actually a lot older than 5 years. I'm presently up and running on a bench supply :-} ...Jim Thompson Shouldn't be hard to find a replacement. Already ordered from Amazon. But bench supply makes for instantaneous getting system back-up ;-) ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food. |
What's with wall warts?
On Sat, 08 Dec 2012 12:31:49 -0700, the renowned Jim Thompson
wrote: What's with wall warts? Do they have a five year warranty clock built-in? I just lost the third wall wart in a month. All of them 5+ years old, or more, so I guess I can't complain. What's to wear out... capacitors? This one was for my Cisco BEFSR81 Router. I think it's actually a lot older than 5 years. I'm presently up and running on a bench supply :-} ...Jim Thompson Caps, and switching supplies can have the startup resistor or the semis die. Also the RoHS solder joints and Chinese assembly may not be so great. Best regards, Spehro Pefhany -- "it's the network..." "The Journey is the reward" Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com |
What's with wall warts?
On Sat, 08 Dec 2012 16:09:16 -0500, Spehro Pefhany
wrote: On Sat, 08 Dec 2012 12:31:49 -0700, the renowned Jim Thompson wrote: What's with wall warts? Do they have a five year warranty clock built-in? I just lost the third wall wart in a month. All of them 5+ years old, or more, so I guess I can't complain. What's to wear out... capacitors? This one was for my Cisco BEFSR81 Router. I think it's actually a lot older than 5 years. I'm presently up and running on a bench supply :-} ...Jim Thompson Caps, and switching supplies can have the startup resistor or the semis die. Also the RoHS solder joints and Chinese assembly may not be so great. Best regards, Spehro Pefhany This one probably pre-dates RoHS. ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food. |
What's with wall warts?
On Sat, 08 Dec 2012 12:31:49 -0700, Jim Thompson
wrote: What's with wall warts? Do they have a five year warranty clock built-in? Yes. The conspiracy theory is that components are selected to survive no longer than the warranty period. I just lost the third wall wart in a month. Check your AC voltage. It may be on the high side. All of them 5+ years old, or more, so I guess I can't complain. What's to wear out... capacitors? Yes. Also sometimes a thermal fuse. Linksys makes two types of wall warts. Your antique is almost surely just a transformer, diode bridge, and electrolytic capacitor. To provide minimal voltage regulation, the transformer is run just below saturation, which causes some heating. The newer types use a switching power supply. They draw no power without a load, are more efficient, but are more sensitive to power line transients. They also tend to spew EMI/RFI. As usual, they kill electrolytics: http://802.11junk.com/jeffl/pics/repair/slides/2Wire-power-supply.html http://802.11junk.com/jeffl/pics/repair/slides/Netgear%20DSA-12R-12.html http://802.11junk.com/jeffl/pics/repair/slides/Motorola-2210-02-PS.html This one was for my Cisco BEFSR81 Router. I think it's actually a lot older than 5 years. Ummm... yeah, that's ancient. There are 4 different hardware versions. From the release notes, the earliest version was Aug 2000 and the latest was last updated in Sept 2009. Yours is somewhere in between. I'm presently up and running on a bench supply :-} Need some spare wall warts? http://802.11junk.com/jeffl/pics/e-waste/slides/wall-warts.html That's about a 3 week collection at the local recycling center. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
What's with wall warts?
On Sat, 08 Dec 2012 22:35:19 -0800, the renowned Jeff Liebermann
wrote: Yes. The conspiracy theory is that components are selected to survive no longer than the warranty period. I think it's more a design spec than a conspiracy. Looking at a typical specs of the internal parts of a linear wall wart- at full rated current, the winding temperature rise is 70°C. At a 30°C average ambient, if we assume the temperature in the wall wart interior rises only 15°C (say half rated current), and 10°C internal cap heating from the ripple current, we'll have the cap at 55°C. With a 105°C/2000 hour rating, we should get Life = 2000 hours * 2^((105-55)/K) where K is 10-15 Assuming K is 15, we get a life of 20,000 hours. Plugged in all the time (24/7) that's about 2-1/3 years. Run it at full rated current in a high ambient and you'll be at a small fraction of that. There are caps that will last longer, but they're too expensive to use in an AC adapter. Best regards, Spehro Pefhany -- "it's the network..." "The Journey is the reward" Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com |
What's with wall warts?
On Sun, 09 Dec 2012 05:43:40 -0500, Spehro Pefhany
wrote: On Sat, 08 Dec 2012 22:35:19 -0800, the renowned Jeff Liebermann wrote: Yes. The conspiracy theory is that components are selected to survive no longer than the warranty period. I think it's more a design spec than a conspiracy. My first clue of a conspiracy was about 15 years ago, when I was fixing a Sony CRT monitor (in the days when Sony made complete monitors). It suffered from the usual electrolytic capacitor failures. On any other brand, I could replace one or two caps, and it would work. However, on this Sony, I discovered that a rather large number of caps failed an ESR test, making repair uneconomical. Inspecting the components, I noticed that there was a wide range of rather strange voltage ratings on the electrolytics. In the past, I would see dozens of electrolytics in a small number of standard values. In this Sony, I saw a rather wide assortment of values and voltages. I didn't do any lifetime calculations, but my impression was that the voltage ratings were calculated for some target lifetime, and no more. The result was near simultenous failure of all the caps. Looking at a typical specs of the internal parts of a linear wall wart- at full rated current, the winding temperature rise is 70°C. At a 30°C average ambient, if we assume the temperature in the wall wart interior rises only 15°C (say half rated current), and 10°C internal cap heating from the ripple current, we'll have the cap at 55°C. With a 105°C/2000 hour rating, we should get Life = 2000 hours * 2^((105-55)/K) where K is 10-15 Assuming K is 15, we get a life of 20,000 hours. Plugged in all the time (24/7) that's about 2-1/3 years. Run it at full rated current in a high ambient and you'll be at a small fraction of that. That sounds a bit on the low side. Let's see how it compares with one of the online capacitor lifetime calculators: http://www.illinoiscapacitor.com/tech-center/life-calculators.aspx For the wall wart, I used: L1 = 2000 hrs Load Life Rating Vr - 16VDC Maximum voltage rating of capacitor Vo - 12VDC Operating voltage of application Tm - 105C Maximum temp rating of capacitor TA - 30C Ambient Temp. which results in 483,000 hrs or 55.1 years. Sheesh, no input box for ripple current. Plugging the same numbers into the above equation: x = (Tm - Ta + Tr) / 10 = (105 - 30 + 10) / 10 = 8.5 L2 = L1 (Vr/Vo)*2^x L2 = 2000hrs*(16/12)*2^8.5 = 2,666*362 L2 = 965,000 hrs = 110 years Here's yet another formula: http://www.low-esr.com/endurance.asp L2 = L1 * 2^(T1-T2/10) = 2000 * 2^((105-30/10)) = L2 = 362,000 hrs = 41.3 years Assuming that I'm not making any of my usual math errors, there seems to be a discrepancy between the various methods of estimating capacitor life. There are caps that will last longer, but they're too expensive to use in an AC adapter. There are extended life capacitors, with up to 10,000 hrs rated life for commodity components. I don't have a clue on pricing. Example: http://www.niccomp.com/help/presentations/AlumE-CapExtendedOperation0809-revA.pdf http://www.low-esr.com/endurance.asp -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
What's with wall warts?
On Sun, 09 Dec 2012 10:18:28 -0800, the renowned Jeff Liebermann
wrote: On Sun, 09 Dec 2012 05:43:40 -0500, Spehro Pefhany wrote: On Sat, 08 Dec 2012 22:35:19 -0800, the renowned Jeff Liebermann wrote: Yes. The conspiracy theory is that components are selected to survive no longer than the warranty period. I think it's more a design spec than a conspiracy. My first clue of a conspiracy was about 15 years ago, when I was fixing a Sony CRT monitor (in the days when Sony made complete monitors). It suffered from the usual electrolytic capacitor failures. On any other brand, I could replace one or two caps, and it would work. However, on this Sony, I discovered that a rather large number of caps failed an ESR test, making repair uneconomical. Inspecting the components, I noticed that there was a wide range of rather strange voltage ratings on the electrolytics. In the past, I would see dozens of electrolytics in a small number of standard values. In this Sony, I saw a rather wide assortment of values and voltages. I didn't do any lifetime calculations, but my impression was that the voltage ratings were calculated for some target lifetime, and no more. The result was near simultenous failure of all the caps. Looking at a typical specs of the internal parts of a linear wall wart- at full rated current, the winding temperature rise is 70°C. At a 30°C average ambient, if we assume the temperature in the wall wart interior rises only 15°C (say half rated current), and 10°C internal cap heating from the ripple current, we'll have the cap at 55°C. With a 105°C/2000 hour rating, we should get Life = 2000 hours * 2^((105-55)/K) where K is 10-15 Assuming K is 15, we get a life of 20,000 hours. Plugged in all the time (24/7) that's about 2-1/3 years. Run it at full rated current in a high ambient and you'll be at a small fraction of that. That sounds a bit on the low side. Let's see how it compares with one of the online capacitor lifetime calculators: http://www.illinoiscapacitor.com/tech-center/life-calculators.aspx For the wall wart, I used: L1 = 2000 hrs Load Life Rating Vr - 16VDC Maximum voltage rating of capacitor Vo - 12VDC Operating voltage of application Tm - 105C Maximum temp rating of capacitor TA - 30C Ambient Temp. which results in 483,000 hrs or 55.1 years. Or 9.7 years using 55 C for the ambient. Sheesh, no input box for ripple current. Plugging the same numbers into the above equation: x = (Tm - Ta + Tr) / 10 = (105 - 30 + 10) / 10 = 8.5 L2 = L1 (Vr/Vo)*2^x L2 = 2000hrs*(16/12)*2^8.5 = 2,666*362 L2 = 965,000 hrs = 110 years Here's yet another formula: http://www.low-esr.com/endurance.asp L2 = L1 * 2^(T1-T2/10) = 2000 * 2^((105-30/10)) = L2 = 362,000 hrs = 41.3 years I assumed 55 C temperature, so you'd get 7 years with that formula. The transformer core and copper loses and capacitor ripple current both heat the cap (plus a bit from the diodes and thermal fuse), and the adapter will heat the air around it to some extent. If the ambient is 30°C (ambient for the adapter), the cap will be warmer when the adapter is plugged in and much warmer when it is doing something. Some of the crappier ones even use 85°C caps. Some of them use crappy lams so they run quite warm to the touch even without load. I'll bet some Chinese caps are 85C marked as 105C. The ones I spec'd I had reasonable confidence they will last 5 years under normal use (so far, so good), but I don't think it would be harder to consistently kill them faster than that. Assuming that I'm not making any of my usual math errors, there seems to be a discrepancy between the various methods of estimating capacitor life. Sure, they are just estimates. There are caps that will last longer, but they're too expensive to use in an AC adapter. There are extended life capacitors, with up to 10,000 hrs rated life for commodity components. I don't have a clue on pricing. Example: http://www.niccomp.com/help/presentations/AlumE-CapExtendedOperation0809-revA.pdf http://www.low-esr.com/endurance.asp From the prices I've seen, it would cost ~10x as much to use the cheapest such 10K-hour caps (maybe doubling the cost of the adapter). They're also physically larger, pushing up the size of the case, pushing up the size of the packaging, and allowing fewer units to fit in a TEU, so increasing sea shipping costs. If you can get, say, 7+ years typical life, and 99% will last more than 5, meet all technical specs and safety requirements, as well as meet the price point marketing wants, what would you choose? Best regards, Spehro Pefhany -- "it's the network..." "The Journey is the reward" Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com |
What's with wall warts?
On Sun, 09 Dec 2012 14:35:59 -0500, Spehro Pefhany
wrote: Here's yet another formula: http://www.low-esr.com/endurance.asp L2 = L1 * 2^(T1-T2/10) = 2000 * 2^((105-30/10)) = L2 = 362,000 hrs = 41.3 years I assumed 55 C temperature, so you'd get 7 years with that formula. Oops. I assumed that ambient meant room temperature or ambient for the entire thermal system, not the maximum capacitor operating temperature. It would have been helpful if the various web pages had specified operating temperature, not ambient temperature. Using 55C results in more realistic lifetimes. Thanks. The transformer core and copper loses and capacitor ripple current both heat the cap (plus a bit from the diodes and thermal fuse), and the adapter will heat the air around it to some extent. If the ambient is 30°C (ambient for the adapter), the cap will be warmer when the adapter is plugged in and much warmer when it is doing something. I've seen the cheap phenol PCB's under the diodes appear somewhat scorched from overheating. I haven't seen that under the capacitor. Using my IR gun type thermometer, the warmest wall wart I could find in the house was 35C, with an (ambient) room temperature of 18C. Obviously, the insides will be warmer, especially if the wall wart is running into transformer core saturation. All of my switchers are the same as ambient. Some of the crappier ones even use 85°C caps. Yep. The electrolyte in 85C caps boils at about 125C, while the 105C caps boil at about 190C. Other than that, there's not much difference between the two types. If you can keep the temperature low, 85C works just as well as 105C. Above 100C(?), the 85C cap develop increased leakage current, while the 105C doesn't leak. On a previous cost cutting expedition for a former employer, I recommended switching to 85C caps. Total parts cost savings would have been about $0.40/radio or maybe $5,000 over the life of the product. The reaction was predictable as I was immediately accused of being a heretic, enemy of the state, and in league with the devil. Walmart quality was thrown in several times. Although it was decided that the possible gain was not worth the risk, I took the time to replace all the 105C caps with 85C caps in the radio, attach thermistors to all the major electrolytic capacitors, and run a 30C to 70C temp test in the env chamber. (The reason for the 30C is that we were low on CO2 for cooling and I didn't care about low temperatures). Since I had to do this anyway to run a preliminary test on some of the other cost cutting measures, it was an easy test. Since there were no ripple current, there was no self heating, so the capacitor temperatures matched that of the oven. I ran a few basic tests and found nothing that would suggest performance deterioration or failure. Upon presenting my results to the committee, I was again labeled a heretic, etc... Some of them use crappy lams so they run quite warm to the touch even without load. I'll bet some Chinese caps are 85C marked as 105C. Of course. Why counterfeit a marginal product when the better quality product is more sellable. Extra credit for fake mil-spec markings. The ones I spec'd I had reasonable confidence they will last 5 years under normal use (so far, so good), but I don't think it would be harder to consistently kill them faster than that. Capacitor brands that work are a favorite topic in the numerous "Bad Caps" forums. What most people seem to ignore is that all the capacitor manufacturers offer different technologies and formulations. Some work, some don't. If someone designs a board which requires high quality low-ESR caps in order to keep the self heating down, and someone later substitutes a different grade from the same manufacturer, of course it's going to fail. It's like buying anything solely by brand name. Every brand has its winners and losers. There are extended life capacitors, with up to 10,000 hrs rated life for commodity components. I don't have a clue on pricing. Example: http://www.niccomp.com/help/presentations/AlumE-CapExtendedOperation0809-revA.pdf http://www.low-esr.com/endurance.asp From the prices I've seen, it would cost ~10x as much to use the cheapest such 10K-hour caps (maybe doubling the cost of the adapter). Ouch. They're also physically larger, pushing up the size of the case, pushing up the size of the packaging, and allowing fewer units to fit in a TEU, so increasing sea shipping costs. If you can get, say, 7+ years typical life, and 99% will last more than 5, meet all technical specs and safety requirements, as well as meet the price point marketing wants, what would you choose? It's usually not my decision. However, the cycle seems to be to initially specify the best quality parts. Contrary to what common sense would suggest, Rev 1.0 usually works fairly well. However, just before the product hits volume production, the cost cutting committee arrives and substitutes the absolute cheapest parts that can be found. When the failures and returns start piling up, an over priced consultant discovers that none of the production units were actually built according to the original parts list. Someone mumbles something about depleting the current stock, so the failures and returns continue to pile up. Better quality parts are eventually introduced just before the product is labeled end of life. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
What's with wall warts?
On Sun, 09 Dec 2012 13:59:13 -0800, the renowned Jeff Liebermann
wrote: Yep. The electrolyte in 85C caps boils at about 125C, while the 105C caps boil at about 190C. Other than that, there's not much difference between the two types. If you can keep the temperature low, 85C works just as well as 105C. Above 100C(?), the 85C cap develop increased leakage current, while the 105C doesn't leak. They'll both work okay at, say 40°C, but according to the formulas, _all_ things being equal, 105°C caps should last about four times longer than 85°C caps. That's why I spec them, not because I think it will ever get to 85°C. They don't cost that much more, are not that much bigger and have a plethora of sources. I also like to have a generous margin on the WV (which one of the forumulas indicates would have an effect on the life- it tends to make the cap a bit bigger and helps dissipate power from the ESR). In both cases, I'm not sure what the real effect on life is, but I have had not had to revisit the choices, which is good. Best regards, Spehro Pefhany -- "it's the network..." "The Journey is the reward" Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com |
What's with wall warts?
Jeff Liebermann writes:
I just lost the third wall wart in a month. Check your AC voltage. It may be on the high side. In another country, I found an alarm wall-wart, 18V/500 mA or so. It was a 50 Hz country and the line voltage was 125VAC+. It had sagged; no longer a rectangle, it had become a parallelgram, with the wall-edge now ~1" higher than the sagging outer face... -- A host is a host from coast to & no one will talk to a host that's close........[v].(301) 56-LINUX Unless the host (that isn't close).........................pob 1433 is busy, hung or dead....................................20915-1433 |
What's with wall warts?
On Sun, 09 Dec 2012 19:49:14 -0600, flipper wrote:
On Sun, 09 Dec 2012 10:18:28 -0800, Jeff Liebermann wrote: On Sun, 09 Dec 2012 05:43:40 -0500, Spehro Pefhany wrote: On Sat, 08 Dec 2012 22:35:19 -0800, the renowned Jeff Liebermann wrote: Yes. The conspiracy theory is that components are selected to survive no longer than the warranty period. I think it's more a design spec than a conspiracy. My first clue of a conspiracy was about 15 years ago, when I was fixing a Sony CRT monitor (in the days when Sony made complete monitors). It suffered from the usual electrolytic capacitor failures. On any other brand, I could replace one or two caps, and it would work. However, on this Sony, I discovered that a rather large number of caps failed an ESR test, making repair uneconomical. Inspecting the components, I noticed that there was a wide range of rather strange voltage ratings on the electrolytics. In the past, I would see dozens of electrolytics in a small number of standard values. In this Sony, I saw a rather wide assortment of values and voltages. I didn't do any lifetime calculations, but my impression was that the voltage ratings were calculated for some target lifetime, and no more. The result was near simultenous failure of all the caps. What you describe is 'design' and not 'conspiracy'. One persons idea of proper design is another persons conspiracy. It's all a matter of perspective. The gray area between the two is a very awkward place to work. I was asked to cost reduce a product I had designed about 3 years previously. I did my best but didn't hit the required "target" price. So, the problem was handed to someone else, who's idea of cost reduction consisted of removing components until the radio ceased to operate. I had designed it to work from 10v to 16.5VDC over a wide temperature range. It was better than what was required. When the cost cutting was done, it mostly worked at room temperature and would only work between 12.5 and 15.0VDC. I tried to keep my changes within FCC guidelines, but such radical changes should have required Part 15 recertification. I kept my mouth shut. Bottom line is they took a decent radio and turned it into a pile of junk. When the problems appeared both on the production line and in the field, I was recovering from surgery and missed the opportunity to tell them the obvious. Design or conspiracy? I would call it a conspiracy. Look, you do not have the choice of making an eternal device because everything fails sooner or later so you can either Que Sera Sera, whatever will be will be, or design for a target life. Question: If I double the useful life of an electronic product, have I also cut sales in half? While various organizations pride themselves in recycling eWaste wherever possible, the same organizations are clueless as to why such products end up as eWaste in the first place. While various EU governments are pushing for cradle to grave "ownership" of electronics, where the manufacturer is responsible for disposal, the same governments seem to have little interest in extending the life of products. While various ecologically correct groups are extolling the virtues of keeping lead out of the environment, the same organizations are oblivious to the effects of unleaded solder has on the life of electronic products. Now, given this fact, What fact? That failure is inevitable and that we should tolerate both the causes and the consequences? We all die eventually, but is that an excuse to live a worthless life? why would you expect someone to design 'section A' for life expectancy X and 'section B' for life expectancy Y when, if either fail, the damn thing is broke? In the not so distant past, I designed marine radios where the customers genuinely expected the radio to last the life of the vessel. The company offered a genuine "lifetime" warranty on it's products. Over the 10 years I spent at this company, I was seeing many older radios arriving for rebuilds and repair. Discussing the situation with management, they indicated that their customers would not buy their higher priced products without the lifetime warranty. They didn't want to do it, but it was a business necessity. Enter Walmart, China manufacture, and cellular phones, all of which institutionalized the concept that products should be temporary, a warranty is a good substitute for quality, and that it's perfectly acceptable to trash 450,000 cell phone PER DAY. When I was doing radios, I was looking at a product sales life of about 5 years. Todays computers are sold for maybe 3-6 months before the new model arrives. I can see a product being recycled after normal wear and tear. I fail to appreciate the same from intentionally designed obsolescence and calculated component failure. If X is too short you've missed the target and if Y is too long you're wasting money. So, fix X so that it lasts longer. True or false? Products with a longer life are better (for the buyer)? Unfortunately things are not that 'precise' and failures are 'rates' rather than a deterministic point in time. This makes things more difficult for designers and companies but puts the lie to 'conspiracy' theories because you simply can't design 'so it fails as soon as the warranty expires', which isn't the purpose of a warranty to begin with. The purpose of the warranty has changed over the years. It was previous a method of dealing with occasional workmanship errors and oversights. It's now the standard method of dealing with shoddy construction, design defects, misuse, and clueless customers. Many products have such a short lifetime, that there's no incentive to fix production line problems, especially when the next THREE generations of replacement products are already somewhere in the design cycle. By the time the complaints come back from the field, the product is already long obsolete. Component failures are 'higher' in the 'early hours' of operation, I.E. infant mortality, drop to a low, and then, as EOL approaches, increase again. Infant mortality is generally due to some form of manufacturing defect (which means process improvements can have a big impact) and is what a warranty is intended to cover so, in fact, after the warranty one should generally be able to expect more 'trouble free' life. You are 'over the hump'. Bathtub curve. http://en.wikipedia.org/wiki/Bathtub_curve The difference is that we never seem to get to the old age, wear and tear, type of failures. Instead, things literally break quite early in the curve. Eventually, the flat bottom of the bathtub curve starts looking like a "V", with the warranty period at the apex of the "V". If the goal is to sell more gizmos, then that's the ideal. If the goal is to keep the stuff out of the landfill, it's disaster. However, since these are all probability distributions over large sample sizes there will always be 'some example' one can point at to supposedly 'prove' any 'theory'. There will be 'one' that seems to last forever, the 'last one to die' (I love these things. Mine lasted 'forever'), and, if you made enough of them, 'one' that failed 2 seconds before, or past, the warranty period. Yeah, I guess, whatever all that means. Reading between your lines, I'll guess you're trying to rationalize the current trend in intentional decreases in product life, durability, and usability. I would be interested to hear how such things improve the quality of life, the environment, and the reputation of the vendor. If we assume that intentionally targeting the product life at slightly over the warranty period is undesirable, that begs the question "What can we do about it"? I have some answers, but they all reek of government intervention and meddling. The best that I can offer is to give the manufacturers and vendors a counter incentive to NOT make throw away products. That will raise costs, but since the rate the consumer buys new gizmos will be correspondingly reduced, the overall cost to the consumers will be about the same. Creating a fashion where used products are considered desirable might also be useful. At this time, shinny new products are some kind of status symbol. If that could be replace with "used is beautiful" or something similar, there might be an incentive for manufacturers to extend the life of their products. [Q] Is a civilization based on throw away everything sustainable? -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
What's with wall warts?
In article ,
Jeff Liebermann writes: The purpose of the warranty has changed over the years. It was previous a method of dealing with occasional workmanship errors and oversights. It's now the standard method of dealing with shoddy construction, design defects, misuse, and clueless customers. Many products have such a short lifetime, that there's no incentive to fix production line problems, especially when the next THREE generations of replacement products are already somewhere in the design cycle. By the time the complaints come back from the field, the product is already long obsolete. It's still possible to learn from problems in the field and feed that into design or purchasing. For example, brand-X caps don't last as long as brand-Y, or all brands of caps die too early - maybe we are running them too hot. Yeah, I guess, whatever all that means. Reading between your lines, I'll guess you're trying to rationalize the current trend in intentional decreases in product life, durability, and usability. I would be interested to hear how such things improve the quality of life, the environment, and the reputation of the vendor. If we assume that intentionally targeting the product life at slightly over the warranty period is undesirable, that begs the question "What can we do about it"? I have some answers, but they all reek of government intervention and meddling. The best that I can offer is to give the manufacturers and vendors a counter incentive to NOT make throw away products. That will raise costs, but since the rate the consumer buys new gizmos will be correspondingly reduced, the overall cost to the consumers will be about the same. Creating a fashion where used products are considered desirable might also be useful. At this time, shinny new products are some kind of status symbol. If that could be replace with "used is beautiful" or something similar, there might be an incentive for manufacturers to extend the life of their products. It would be interesting to get lifetime data on consumer electronics. Does anybody like Consumer Reports collect and publish it? -- These are my opinions. I hate spam. |
What's with wall warts?
On Mon, 10 Dec 2012 10:50:40 -0800, Jeff Liebermann
wrote: Incidentally, http://www.blippee.com/gilbert.html "Look at Gilbert toys first...they last!" I guess that's a dead motto. This one only lasted a year (1951-52) http://daily-grind.net/most-dangerou...ic-energy-lab/ |
What's with wall warts?
On Mon, 10 Dec 2012 10:50:40 -0800, Jeff Liebermann
wrote: However, when I have a to deal with a committee of clueless "suits" that want cheaper no matter what it does to their quality, and then comes back a few months later and tries to blame the engineers for the returns and failures, I tend to call it a conspiracy. Lacking a better name for the process, I'll continue to call it a conspiracy. Bad management, not conspiracy. "Never attribute to malice that which is adequately explained by stupidity." |
What's with wall warts?
In article ,
Spehro Pefhany wrote: However, when I have a to deal with a committee of clueless "suits" that want cheaper no matter what it does to their quality, and then comes back a few months later and tries to blame the engineers for the returns and failures, I tend to call it a conspiracy. Lacking a better name for the process, I'll continue to call it a conspiracy. Bad management, not conspiracy. "Never attribute to malice that which is adequately explained by stupidity." Agreed. "Shortsightedness" is another adjective for what's happening. It's not quite the same thing as "stupidity", because (in cases like this) the "suits" are specifically optimizing for a desired goal (lower cost and higher sales, NOW), and are ignoring the longer-term costs (returns, failures, loss of sales). In a sense, it's a very rational behavior pattern. If you don't plan on working for the same company for at least 5-10 years, then it can make good sense to focus only on your own short-term position. To some extent, this "flows downhill" from the current Wall Street financial system, in which companies' values depend very highly on their short-term results (e.g. quarterly). In this environment, "long-term" thinking means "next year" if you're lucky. Since project managers and VPs tend to receive financial incentives for achieving short-term deliverable results, meeting tight schedules, and cutting costs, there's a serious risk of a company "eating its seed corn". I once had the displeasure of working for a company vice president who gloried in this sort of short-term focus... "get the current product out the door" was Job 1, and there really wasn't a Job 2. Bug-fixing, work on product infrastructure, and any design and development work which wasn't directly tied to a new feature was almost entirely de-funded. He felt that the best way to achieve product goals was to "hire a hundred code monkeys", throw it together, kick it out the door, and then start over again. Two or three years of this, and the product quality had taken a really serious downturn, customers were unhappy, engineers were miserable, and it was becoming very difficult to do any new development because the existing product technology was buggy, brittle, and full of short-term hacks. The company developed one hell of an "engineering debt" during this VP's reign, and it took years (and a lot of money) to recover after the VP suddenly took a higher-status job at a competing company. I felt more than a bit sorry for the competitor! As we walked out of the meeting where we were informed that this particular VP had suddenly resigned, one of my coworkers remarked "I don't know about you, but I'm hearing an angelic choir singing right now." I knew just how he felt! There are a few things engineers stuck in this sort of "clueless suit" situation can do: make your concerns known to higher management (in writing if possible) in a professional and responsible manner, keep a good "Pearl Harbor" file (a record of all such orders and conversations), and keep your powder dry (look for other companies which don't have quite such a corporate death-wish). -- Dave Platt AE6EO Friends of Jade Warrior home page: http://www.radagast.org/jade-warrior I do _not_ wish to receive unsolicited commercial email, and I will boycott any company which has the gall to send me such ads! |
What's with wall warts?
On Mon, 10 Dec 2012 14:47:44 -0500, Spehro Pefhany
wrote: On Mon, 10 Dec 2012 10:50:40 -0800, Jeff Liebermann wrote: Incidentally, http://www.blippee.com/gilbert.html "Look at Gilbert toys first...they last!" I guess that's a dead motto. This one only lasted a year (1951-52) http://daily-grind.net/most-dangerou...ic-energy-lab/ Chuckle. At the time, there were promotions for the "friendly atom" which included nuclear powered automobiles and airplanes. I was only 3 years old at the time, so I didn't get this toy for my birthday. Natural uranium is 0.7 micro Curies, which is not very much. Some basics: http://nuclearhistory.wordpress.com/2011/02/28/radioactivity-of-uranium/ A lump of natural uranium isn't dangerous, unless you're worried about heavy metal poisoning from the minerals usually associated with natural uranium deposits. Of course, public paranoia eventually proscribed all forms of radioactivity, including the Thorium in Coleman lantern mantles etc. The thorium mantles were noticeably brighter than the current yttrium variety. In 2002, I had to endure a radioactive treadmill stress test to see if my heart was functioning properly. I had my Geiger counter in my car, but didn't have the guts to take it into the hospital with me. Part of the procedure was to inject me with Thallium 201. After the test, I went to the local (nearby) electronics store, fired up my Korean War era Geiger counter, and pegged it with 20,000+ counts per minute. The reaction was interesting. Anyone that was 50 years or older, immediately jumped away backwards when they heard the roar of the counter. My calculations of their exposure rate did not make them any happier. Nobody would go anywhere near me. However, those under 50, had never had any classes or experience with radioactivity in the skools, and usually asked something mundane like "What's that noise"? The effect was sufficiently interesting (to me) that I repeated my Geiger counter demonstration at some of my customers along the route between the hospital, my office, and my home. Unfortunately, it was only good for about two days as the half life of Thallium 201 is only 3 days. Some of my friends and customers still refuse to forgive me for nearly creating a panic in the homes and offices. I was also repeatedly asked a rather odd question, which had me mystified for a while. They asked "Why do you have a Geiger counter"? It was much later that I realized that they were really asking was if I was conducting dangerous radioactive experiments at home. I've also given brief demonstrations with the Geiger counter and home made scintillation counter in skools and at radio club meetings. The reactions varied from extreme curiosity to running away in horror. Most of the horror came from administrators and officials. I managed to worry a few parents when I demonstrated that a granite countertop and potassium salt were hot: http://healthyliving.blog.ocregister.com/2011/04/01/7-household-items-that-contain-radiation/ This was from the salt demo: http://802.11junk.com/jeffl/crud/salt.jpg Gilbert had the right idea. We seem to need some education in basic radioactivity. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
What's with wall warts?
Jim Thompson wrote:
What's with wall warts? Do they have a five year warranty clock built-in? I just lost the third wall wart in a month. All of them 5+ years old, or more, so I guess I can't complain. What's to wear out... capacitors? This one was for my Cisco BEFSR81 Router. I think it's actually a lot older than 5 years. I'm presently up and running on a bench supply:-} ...Jim Thompson The "old" style = = unregulated is symple, xfmr,2 diodes, cap with the xfmr a little under-rated (for smallest size) and gets a bit warm. Crappy design as they all put out more voltage AT FULL LOAD thantheir "specification". Xfmr heat slowly cooks the cheap cap to death. |
What's with wall warts?
On Mon, 10 Dec 2012 22:06:54 -0800, the renowned Robert Baer
wrote: Jim Thompson wrote: What's with wall warts? Do they have a five year warranty clock built-in? I just lost the third wall wart in a month. All of them 5+ years old, or more, so I guess I can't complain. What's to wear out... capacitors? This one was for my Cisco BEFSR81 Router. I think it's actually a lot older than 5 years. I'm presently up and running on a bench supply:-} ...Jim Thompson The "old" style = = unregulated is symple, xfmr,2 diodes, cap with the xfmr a little under-rated (for smallest size) and gets a bit warm. Four diodes and a thermal fuse (the latter to meet safety requirements). Getting warm has a lot to do with how low end the lams are. Paying a few cents more buys more efficiency and meets those standards. Crappy design as they all put out more voltage AT FULL LOAD thantheir "specification". Not what I've seen. They put out the spec voltage at full load. 9V nominal adapter.. open circuit 13.48V, full load 8.96V. Xfmr heat slowly cooks the cheap cap to death. Yup. Put another equal size cap in the product and you can let the one in the adapter die. Best regards, Spehro Pefhany -- "it's the network..." "The Journey is the reward" Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com |
What's with wall warts?
Spehro Pefhany wrote:
On Mon, 10 Dec 2012 22:06:54 -0800, the renowned Robert Baer wrote: Jim Thompson wrote: What's with wall warts? Do they have a five year warranty clock built-in? I just lost the third wall wart in a month. All of them 5+ years old, or more, so I guess I can't complain. What's to wear out... capacitors? This one was for my Cisco BEFSR81 Router. I think it's actually a lot older than 5 years. I'm presently up and running on a bench supply:-} ...Jim Thompson The "old" style = = unregulated is symple, xfmr,2 diodes, cap with the xfmr a little under-rated (for smallest size) and gets a bit warm. Four diodes and a thermal fuse (the latter to meet safety requirements). Getting warm has a lot to do with how low end the lams are. Paying a few cents more buys more efficiency and meets those standards. * I have opened many unregulated wall warts,from el-cheapo to top-of-the-line, and NEVER seen any thermal fuse, period. Crappy design as they all put out more voltage AT FULL LOAD thantheir "specification". Not what I've seen. They put out the spec voltage at full load. * I have NEVER seen an unregulated wall wart like that,ever. And i have seen an un-countable number of them in (about) 40 years. Now, even the el-cheapo regulated ones (eg: linear series pass) do meet label specs. Switchers are better yet. 9V nominal adapter.. open circuit 13.48V, full load 8.96V. Xfmr heat slowly cooks the cheap cap to death. Yup. Put another equal size cap in the product and you can let the one in the adapter die. Best regards, Spehro Pefhany |
What's with wall warts?
Robert Baer wrote: * I have opened many unregulated wall warts,from el-cheapo to top-of-the-line, and NEVER seen any thermal fuse, period. Did you take apart all the transformers? The thermal fuses are usually in a slot, in the molded bobbin to get them closer to the core. |
What's with wall warts?
On Tue, 11 Dec 2012 19:15:00 -0800, Robert Baer
wrote: * I have opened many unregulated wall warts,from el-cheapo to top-of-the-line, and NEVER seen any thermal fuse, period. Well, they're normally hidden under a layer of insulating tape on the transformer (in series with the primary), so a casual examination might not detect it. If they're UL class 2 they need to limit- in some cases they've made the winding self-fusing, in others they use a thermal fuse. I don't think self-fusing* cuts the mustard world-wide with the safety authorities, so I've seen mostly thermal fuses in approved linear adapters these days. Eg. http://www.cui.com/Product/Resource/...0050-P5-SZ.pdf ... has a 130°C thermal fuse I can't share the spec sheets of the ones I source, but they specify the thermal fuse rating and UL/CSA approved part numbers and manufacturers. Crappy design as they all put out more voltage AT FULL LOAD thantheir "specification". Not what I've seen. They put out the spec voltage at full load. * I have NEVER seen an unregulated wall wart like that,ever. And i have seen an un-countable number of them in (about) 40 years. What are the test conditions? The ones I've bought in production quantities do what the specs say, the test reports say, and what the label says, under the appropriate test conditions. If they didn't meet the specifications at incoming inspection they'd be sent back! Did you adjust the input AC voltage to the specified voltage and put an accurate programmable load on the output? They always read a LOT higher with a light load, some are 50% worse than others. Now, even the el-cheapo regulated ones (eg: linear series pass) do meet label specs. Where do you find those? I was looking for some and they don't seem to be very popular these days. Twenty years ago, they were more common. It's kind of stupid to put the regulator in that little box- easier to get rid of the heat elsewhere and not have to worry about the voltage drop in the cord and connector. Switchers are better yet. For some things.. some of the cheap crap ones are missing Y caps so they have (unspecified) HF common mode noise on the output relative to earth. Some of the ones that have Y caps are using unapproved and probably unsafe caps. Many of them have a lot of ripple and are pushing the output caps hard enough they'll likely die sooner than the linear unregulated adapters. Cheap ones may be missing common mode input filters so they'll conduct noise. * with self fusing, the wire insulation melts, causing shorted turns, which draws enough current to fuse the copper wire or to blow a non-thermal fuse in series with the primary. Since copper melts at a higher temperature than the tape and fish paper can withstand, it has to be shown that it won't compromise isolation. |
What's with wall warts?
Cooking the caps.
Larry In article , Jim Thompson wrote: What's with wall warts? Do they have a five year warranty clock built-in? I just lost the third wall wart in a month. All of them 5+ years old, or more, so I guess I can't complain. What's to wear out... capacitors? This one was for my Cisco BEFSR81 Router. I think it's actually a lot older than 5 years. I'm presently up and running on a bench supply :-} ...Jim Thompson |
What's with wall warts?
"Lawrance A. Schneider" wrote in message ... Cooking the caps. Larry In article , Jim Thompson wrote: What's with wall warts? Do they have a five year warranty clock built-in? I just lost the third wall wart in a month. All of them 5+ years old, or more, so I guess I can't complain. What's to wear out... capacitors? This one was for my Cisco BEFSR81 Router. I think it's actually a lot older than 5 years. I'm presently up and running on a bench supply :-} ...Jim Thompson Hi Jim, most likely top posting by newbies:-( I don't know why, but the switching warts seem to hold up better, maybe it is less generated heat. The transformer ones seem to quit when the thermal fuse on the primary lets go. Tom |
What's with wall warts?
On Thu, 24 Jan 2013 20:24:13 -0500, "hifi-tek"
wrote: "Lawrance A. Schneider" wrote in message ... Cooking the caps. Larry In article , Jim Thompson wrote: What's with wall warts? Do they have a five year warranty clock built-in? I just lost the third wall wart in a month. All of them 5+ years old, or more, so I guess I can't complain. What's to wear out... capacitors? This one was for my Cisco BEFSR81 Router. I think it's actually a lot older than 5 years. I'm presently up and running on a bench supply :-} ...Jim Thompson Hi Jim, most likely top posting by newbies:-( I don't know why, but the switching warts seem to hold up better, maybe it is less generated heat. The transformer ones seem to quit when the thermal fuse on the primary lets go. Tom This was a switching one. ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food. |
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