What's going on with consumer market products' PSUs? - Page 1
Forum section: electronics / general

author: nuno
author_rank: Frequent Contributor
timestamp: May 07, 2018, 01:20:12 pm
content: In the last year or so, I shifted occupation a little and also started repairing electronics in small appliances (such as dehumidifiers or peltier-based fridges) and air conditioned controller boards. And I already see a strong pattern: in 85%+ of the cases, the problem is in the mains AC to DC converter. Be it an indoors appliance or outdoors, old or new, the fault is most likely in the PSU.I look at some of the controller chips datasheets and see that they're all full of protections, nevertheless some of those even roughly explode.So, what's going on with consumer market PSUs? Bad components? Bad design? Bad implementation? Bad requirements? Bad mains? What? Please share your thoughts...

author: b_force
author_rank: Super Contributor
timestamp: May 07, 2018, 01:24:15 pm
content: Saving just a few cents to much on the most critical parts and places in a design.

author: Ampera
author_rank: Super Contributor
timestamp: May 07, 2018, 01:25:07 pm
content: bust the PSU, and stupid people will keep buying your product.

author: Miyuki
author_rank: Frequent Contributor
timestamp: May 07, 2018, 01:33:24 pm
content: It is simple just planned lifeAt PSU you can very easy plan how long it will work and when it bang, so marketing can easy say give us 3 year ones and 85%+ of them will die at third year

author: bob225
author_rank: Frequent Contributor
timestamp: May 07, 2018, 01:35:28 pm
content: One word. ChinaThe lowest bidder wins the contract - use the cheapest components on the Shenzhen market, The biggest component failure on psu's are the caps

author: TimNJ
author_rank: Super Contributor
timestamp: May 07, 2018, 01:45:13 pm
content: I don't think cutting corners on the power supply is a particularly new trend. It's probably the part of the system that is easiest to save cost on, and hardest to justify (to management, et al.) spending extra on. Why buy that 4A/12V Delta when you can buy 4A/12V Brand-X for 1/4 the price? MTBF? Doesn't matter as long as most of them last through the short warranty period.Not as much as the power supply manufacturers' fault, as it is the companies looking for absolute bottom of the barrel prices.

author: bob225
author_rank: Frequent Contributor
timestamp: May 07, 2018, 01:57:24 pm
content: late 2000's Samsung products have major issues with caps, 2 year old 50" LCD got skipped for £2.50 worth of decent cap's as it was cheap to "replace it"Hotpoint moved there control board manufacturing to Romania to cut costs, the supply side caps blow, and the soldering looks like its been done by a 5 year oldanother issue I have come across is pcb quality - just show the iron to the board and it lifts the copper

author: b_force
author_rank: Super Contributor
timestamp: May 07, 2018, 02:04:08 pm
content: I have seen mainly 85C caps were a good thinking person would use at least a 105C capOr similar issues like that (with inductors/transformers etc)

author: nctnico
author_rank: Super Contributor
timestamp: May 07, 2018, 04:48:04 pm
content: Quote from: b_force on May 07, 2018, 02:04:08 pmThat doesn't have to be bad perse. There are long life 85C caps and short life 105C caps.But in case of consumer equipment they probably opted for the cheapest one that gets the device through the warranty period. However in the EU a piece of equipment needs to have a reasonable life span so manufacturers don't get away with crap which just lasts until the warranty of over.

author: TimNJ
author_rank: Super Contributor
timestamp: May 07, 2018, 05:01:23 pm
content: Quote from: nctnico on May 07, 2018, 04:48:04 pmJust curious, is there some sort of minimum warranty for consumer products in the EU? i.e. If a company only states a 1 year warranty, then it can still get away with producing crap.What's the incentive for the EU to do this? More reliable products = money savings for consumers = more spending power?

author: nctnico
author_rank: Super Contributor
timestamp: May 07, 2018, 05:09:00 pm
content: Quote from: TimNJ on May 07, 2018, 05:01:23 pmNo minimum warranty in the EU is two years (Apple and Dell have paid hefty fines already for implementing this too slow). Other than that equipment must have a reasonable life span. If something fails too quickly the seller must pay part of the repair cost depending on how old the device is and how long it is supposed to last.The idea is to reduce the amount of e-waste and get better value for money.

author: nuno
author_rank: Frequent Contributor
timestamp: May 08, 2018, 01:58:00 am
content: This is all a very big problem, because the fixing cost is mostly work, so most appliances are going to the recycle/trash mostly working...

author: b_force
author_rank: Super Contributor
timestamp: May 08, 2018, 08:41:24 am
content: Quote from: nuno on May 08, 2018, 01:58:00 amWelcome to a world were it's all about profit

author: madires
author_rank: Super Contributor
timestamp: May 08, 2018, 10:23:05 am
content: Quote from: nctnico on May 07, 2018, 05:09:00 pmThat's new to me. Just for your country or the whole EU? Any links?

author: David Hess
author_rank: Super Contributor
timestamp: May 08, 2018, 12:05:27 pm
content: I think they have just gotten better at designing for a specific operating life and warranty duration. Aluminum electrolytic capacitors especially have become reliable "timers" based on ripple current rating and operating life so they can be "tuned" to fail at close to a specified time.

author: schmitt trigger
author_rank: Super Contributor
timestamp: May 08, 2018, 01:19:04 pm
content: I used to work for a power supply company, and my feeling was and still is, that for most customers power supplies are an afterthought.They spend all the time and R&D dollars on the product itself (not a wrong thing to do, I might add) and then when the remaining budget will not allow anything more complex than a cord, they scramble fanatically to find the cheapest power solution.A true story: a state of the art optical multiplexer/router. The main board was beyond awesome: a 10'' x 14", 8 layer board, crammed full with all sorts of esoteric and premium components. Gold plating everywhere. The sheer number of components and overall complexity was mind boggling.It was powered from the cheapest power supply in our catalog, a PSU originally designed for a low cost printer.The contrasts could not be more stark: the PSU board was a thru-hole, single sided CEM1 job.Long story short: there were many factory failures. The root cause was that, to save a few pennies, they had specified that the DC output header to be unkeyed, meaning that the operators could by mistake reverse the connector while assembling the unit.I suggested a keyed connector like the one in the photo, but the customer engineering never gave the approval. Citing backward compatibility issues, etc.

author: b_force
author_rank: Super Contributor
timestamp: May 08, 2018, 01:35:22 pm
content: Yep, very recognizable story.Of course that doesn't only counts for just PSU's but for many other things as well.I guess that divides the really good products from the pile of mediocre stuff.

author: Electro Detective
author_rank: Super Contributor
timestamp: May 09, 2018, 01:28:00 am
content: For those who wield a soldering iron competently:Don't buy a product you can't get into easily, check out some Teardown videos or posts before dropping your cashNo matter how good quality it appears to be and manufacturers golden rep is, order a better cap kit for it asap, label and store it appropriatelyMark on your date calender two weeks after the warranty expires *Fast forward * to that future date when the unit 'mysteriously' misbehaves or claps outGet out the cap kit, soldering rig and whatever your fav beverage isMoney well spent I reckon

author: Cerebus
author_rank: Super Contributor
timestamp: May 09, 2018, 01:55:42 am
content: Quote from: Electro Detective on May 09, 2018, 01:28:00 amBearing in mind that the shelf life specifications of electrolytic capacitors are often significantly worse than their specified life under bias this may not be the wisest approach.

author: JohnnyMalaria
author_rank: Super Contributor
timestamp: May 09, 2018, 02:20:29 am
content: Quote from: nctnico on May 07, 2018, 05:09:00 pmIn the UK, theConsumer Rights Act of 2015requires "goods to be of satisfactory quality" and:(1) Every contract to supply goods is to be treated as including a term that the quality of the goods is satisfactory.(2) The quality of goods is satisfactory if they meet the standard that a reasonable person would consider satisfactory, taking account of—(a) any description of the goods,(b) the price or other consideration for the goods (if relevant), and(c) all the other relevant circumstances (see subsection (5)).(3) The quality of goods includes their state and condition; and the following aspects (among others) are in appropriate cases aspects of the quality of goods—(a) fitness for all the purposes for which goods of that kind are usually supplied;(b) appearance and finish;(c) freedom from minor defects;(d) safety;(e) durability.Fair to say that I would consider very unsatisfactory premature power supply failure.

author: rdl
author_rank: Super Contributor
timestamp: May 09, 2018, 02:52:11 am
content: I seem to remember a discussion here about the shelf life of electrolytic caps and that the general consensus was that they are likely to be as good as new even after 20 years or more.

author: Electro Detective
author_rank: Super Contributor
timestamp: May 09, 2018, 03:38:35 am
content: My comment above assumed members here would go for good reputable capacitors with long-ish shelf lifeand or use them for other projects in the meantime if requiredand or in the rare event the product they were intended for actually went the distance via decent PSU componentsHey, miracles can happen, right...?

author: CJay
author_rank: Super Contributor
timestamp: May 09, 2018, 06:12:03 am
content: Quote from: madires on May 08, 2018, 10:23:05 amThe whole EU.https://europa.eu/youreurope/citizens/consumers/shopping/guarantees-returns/faq/index_en.htmIn the UK at least we actually have laws that better this, you can still claim for repairs during the expected lifespan of an item so, it could be up to six years.But good luck finding a retailer who is willing to honour that without an argument, it's hard enough to get them to comply with the 2 year laws.https://www.theguardian.com/money/2006/mar/25/consumernews.howtocomplain

author: madires
author_rank: Super Contributor
timestamp: May 09, 2018, 09:30:19 am
content: Thanks, but the first link is an FAQ about the 2 year EU legal guarantee. I'm interested in the prolonged period during which the seller has to pay the repair partly.

author: CJay
author_rank: Super Contributor
timestamp: May 09, 2018, 10:03:33 am
content: Quote from: madires on May 09, 2018, 09:30:19 amI would have thought that was implicit in the FAQ, it says several times that the seller must repair at no cost to the consumer so that would mean they must pay the repair cost if the repairer charges surely?

author: madires
author_rank: Super Contributor
timestamp: May 09, 2018, 01:59:33 pm
content: AFAIK the seller has to manage the repair. Only if the seller declines to fix the problem you may ask some service company to repair the device and then collect the money from the seller which will involve a lawsuit most likely. This is part of the EU legal guarantee. nctnico has mentioned some additional rule about reasonable life spans. So I'd guess that when a washing machine is meant to last 10 years and breaks during that time I would call the service and the seller would have to pay a reasonable part of the repair. Of course I might have misunderstand nctnico.The topic isn't easy to understand since there's also a commercial guarantee quite often and a lot of sellers try to direct the customer in that direction to avoid or minimize the costs they would have with the legal guarantee. For example, your new TV has a 3 years commercial guarantee besides the legal guarantee. After a month or so the TV breaks and you inform the seller while asking for a repair. If the seller plays the commercial guarantee card you might have to wait 2 or 3 months to get the TV repaired (the manufacturer has defined a maximum repair time of 3 months in his commercial guarantee). But if you insist on the legal guarantee the seller has to fix the TV within a reasonable time, like 3 weeks.