i won't buy chinise parts from aliexpress or ebay - Page 1
Forum section: electronics / general

author: cmrincon
author_rank: Newbie
timestamp: February 11, 2020, 09:21:30 am
content: Hey!I want to share with you a short story about how not to save money:Yesterday i was learning about mosfets amps and i decided to use a few 2n7000 N-channel mosfet which i got from aliexpress time ago. I did the maths, even i simulated the circuit. When i mounted the circuit in my breadboard i could see that the mosfet was in ohm region and with a volt above VTh the drain current was more than it could handle, no matter if i slightly drop down vgs, the circuit still didn't work because my mosfet didn't behaves as datasheet and it was useless for amplification ( maybe for switching purposes).Few weeks ago i get capacitors from another chinise vendor on ali, and i used them to repair a sat receiver. Yesterday i got to repair it again, was hard because i couldn't see at first glance what was wrong with the receiver, but after a few test i repaired it. Guess what was wrong? the chinise capacitors!I can't belive that all chinise parts are like this ones, and i gave my last chance to lcsc. I bought some MMBTH10, ceramic caps and few rf npn bjts from not chinise manufacturer.In a month i will know if i will loose the money or it is a cheap way to buy parts.Don't buy not original parts!!

author: Quarlo Klobrigney
author_rank: Super Contributor
timestamp: February 11, 2020, 09:31:42 am
content: Internet grammar police here...You have employed a double negative. Your statement reads that youwillbuy from Aliexpress.

author: Pinkus
author_rank: Frequent Contributor
timestamp: February 11, 2020, 09:54:48 am
content: Well, I guess you learned from that lesson.... as many of us did before.Unfortunately there are enough cheapos left so the problem will not vanish.

author: Mechatrommer
author_rank: Super Contributor
timestamp: February 11, 2020, 10:47:47 am
content: i won't never buy chinise parts from aliexpress or ebay = i will buy chinise parts from aliexpress or ebayDon't buy not original parts!! = buy original parts!!both points are valid imho... its just we learn to read the spec and make it half or a third capability when it comes to china clone parts.. with 1/10X the price, still bang for the buck, in certain occasions. ymmv.

author: cmrincon
author_rank: Newbie
timestamp: February 11, 2020, 11:20:03 am
content: I'm sorry, i modified the topic in order to avoid confusions!

author: exe
author_rank: Unknown
timestamp: February 11, 2020, 11:55:10 am
content: Welcome to the club.I do buy ICs from ali sometimes, but only if don't have another source, or if I'm willing to accept the risk and I can verify part's performance before putting it into the circuit.What was motivation to buy such a jelly bean component from China? It costs nothing from any reputable distributor. The only catch is "minimal order" and delivery cost.

author: SilverSolder
author_rank: Super Contributor
timestamp: February 11, 2020, 04:42:51 pm
content: I happily buy Chinese parts on eBay. Most of the time, they are good. When they are not, I raise a case with eBay and get a refund. There isn't really any risk involved, but you do have to test/verify the parts when you get them.

author: wraper
author_rank: Unknown
timestamp: February 11, 2020, 04:47:34 pm
content: Quote from: SilverSolder on February 11, 2020, 04:42:51 pm"Good" in quote marks. When they work in your circuit does not mean they are genuine or meet specifications. Often you can get recycled crap sold as new and with 20% of duds. Even when parts are genuine there is high chance they were re-marked with newer date code and have poor solderability due to old age and poor storage conditions.

author: Quarlo Klobrigney
author_rank: Super Contributor
timestamp: February 11, 2020, 05:00:28 pm
content: Probably been seen here before, but it was new to me..

author: tunk
author_rank: Super Contributor
timestamp: February 11, 2020, 05:07:13 pm
content: Not everyone have had the same bad experience:Andreas Spiess recently tested some transistors fromAliExpress and found that all except one were within spec:

author: NivagSwerdna
author_rank: Super Contributor
timestamp: February 11, 2020, 05:08:41 pm
content: FWIW I've bought lots of chips from China that do work... and some that don't. For NOS items you probably don't have much choice as to supplier.For any quantity or long term supply purchasing then you need to go to a proper supplier not swim with the sharks on ebay.

author: SilverSolder
author_rank: Super Contributor
timestamp: February 11, 2020, 05:32:00 pm
content: I have had bad/fake transistors from eBay, but most of the time they are good. If the price is low enough, I don't mind testing - for hobby purposes. Anything serious, and I would head for a serious supplier.

author: DBecker
author_rank: Frequent Contributor
timestamp: February 11, 2020, 06:51:07 pm
content: I was bitten badly back in the great power MOSFET shortage a decade ago with re-marked lower capability parts. I've also gotten obviously fake security transponders.Parts that are obsolete or in high demand are commonly counterfeit/re-marked. Cheap commodity components, or parts that went out of production in favor of a similar new part can be a great deal for a hobby project where you don't need a large or long-term supply.

author: janoc
author_rank: Super Contributor
timestamp: February 11, 2020, 07:00:28 pm
content: Quote from: tunk on February 11, 2020, 05:07:13 pmThat's not quite true. They were good enough for his project, but a claim of a part "being within specs" (as in datasheet specs) is something very different. He didn't really test that - and I am prety sure some would have failed if he has pushed them to the actual published datasheet specs. The testing in that video is a good sanity check that you didn't get something wildly different or completely fake (like those Sparkfun "ATMegas") but it won't tell you if the part is really genuine and meets all its specs.That may or may not be important for you, it depends on your project.However, it is an important distinction to make or you will get a surprise that that MOSFET or a voltage regulator blew up at half of the rated current or that the opamp is 3x noisier and has 1/4 of the expected slew rate - all due to cheap lower spec parts being remarked and sold as higher spec ones and your circuit actually taking advantage of the published specifications.Recycled but original parts are not necessarily a problem if you know what you are buying (given that you are unlikely to find another source anyway) - but if someone is selling a part that is 20-30 years out of production and claims it is new, with recent date codes, then there is something fishy there ...

author: Marco
author_rank: Super Contributor
timestamp: February 11, 2020, 07:03:36 pm
content: Quote from: cmrincon on February 11, 2020, 09:21:30 amTrue 2n7000s are the most statically sensitive component a hobbyist will handle (but shouldn't). You can juggle PC memory made with the tiniest of modern processes without much fear, but look wrong at a 2n7000 and it's kaput.Breadboarding with them is silly, use parts with proper gate protection.PS. a lot of them have gate protection now regardless of the datasheet, but you might have some NOS of proper ones.

author: cmrincon
author_rank: Newbie
timestamp: February 11, 2020, 09:36:00 pm
content: Quote from: exe on February 11, 2020, 11:55:10 amSometimes i'm bored and i buy things that i really don't need, but i think that they will be useful in the future, they cost only a few euros and i think that it is like a little adiction.When i buy a part from ebay/ali i will never expect to have parts with the exact behaivor than the original one, but at least i expect that they would have similar specs as i'm not a proffesinal and this is only my hobby. Maybe this are only a few bad experiences in a short period of time.Quote from: Marco on February 11, 2020, 07:03:36 pmDo you have any mosfet suggestion? i'm searching for a mosfet with a low input/output capacitance (100p-200p max) and a max power dissipation of 1 w

author: exe
author_rank: Unknown
timestamp: February 11, 2020, 09:46:11 pm
content: Quote from: cmrincon on February 11, 2020, 09:36:00 pmWell, I doTune search to your likinghttps://www.digikey.nl/products/en/discrete-semiconductor-products/transistors-fets-mosfets-single/278?k=&pkeyword=&sv=0&pv1174=121220&pv1174=121231&pv1174=121242&pv1174=121250&sf=1&FV=-8%7C278%2Cmu200pF%7C2263%7C1&quantity=&ColumnSort=0&page=1&nstock=1&pageSize=25

author: Psi
author_rank: Super Contributor
timestamp: February 11, 2020, 09:55:21 pm
content: The problem people run into with aliexpess is ordering by price and buying the cheapest option, because they are so used to doing that on other sites.The correct thing to do is order by price and then look for the different price groupings. They will be in clusters.The lowest price grouping should be ignored at all costs. This is where you will find total fakes and factory rejects that are way out of spec.The 2nd and 3rd price grouping is what you want to order. These will be good parts.NOTE1: Even 2nd and 3rd group may still be factory rejects but will be good enough 99% of the time. If you want 100% good and in spec parts your buying from the wrong place. Aliexpress is not for that.Aliexpress is for when you don't mind a little risk in order to save 50-90% of the cost from a genuine supplier. Expecting 100% genuine pars at 50-10% price is stupid.NOTE2: Never buy from an Aliexpress seller with less than 95% feedback score.NOTE3: Pick your battles, if you're building something first decide what parts are critical to you and what parts don't matter much.You might choose to get your transistors and IC's from digikey but get your LEDs, resistors and switches from aliexpress because those are less critical. If the LED brightness is a little off it wont matter.

author: wraper
author_rank: Unknown
timestamp: February 11, 2020, 10:08:25 pm
content: Quote from: Psi on February 11, 2020, 09:55:21 pm99% good is gross overestimation. Depending on what you buy they easily may be the same crap as the cheapest tier.

author: floobydust
author_rank: Super Contributor
timestamp: February 11, 2020, 10:15:46 pm
content: If you buy the lowest price parts from a store that also sells pantyhose and cosmetics, well- it might be high risk.Some eBay/Ali stores are a bit more expensive and sell OK parts but never in anti-stat packaging or with real markings. There seems to be a mystery laser doing all IC/transistor markings in china.Lately I just buy from Digikey or Mouser. Because it is false savings after the wasted time pissing around with fake/dud/counterfeit parts.

author: Marco
author_rank: Super Contributor
timestamp: February 12, 2020, 09:43:19 am
content: Quote from: cmrincon on February 11, 2020, 09:36:00 pmUse automotive rated parts, even if it's not on the datasheet they can't pass the tests without gate protection. I only found one through hole one, theBS107P.I'm not sure how many versions of 2n700x without gate protection are even made any more, but Infineon says their one is ESD class 0 so it seems they are still being made.

author: exe
author_rank: Unknown
timestamp: February 12, 2020, 10:05:15 am
content: An alternative could be an smd part with a through-hole adapter board if TH mounting absolutely needed. Or, may be, BJT would be a better option? We need to know more about the application...

author: SilverSolder
author_rank: Super Contributor
timestamp: February 12, 2020, 12:32:06 pm
content: Quote from: cmrincon on February 11, 2020, 09:36:00 pmWelcome to the club...

author: janoc
author_rank: Super Contributor
timestamp: February 12, 2020, 03:56:42 pm
content: Quote from: Marco on February 11, 2020, 07:03:36 pmEh, they are OK, even on a breadboard if you are careful.IMO, it is a good opportunity to learn and use proper ESD precautions, e.g. an antistatic mat on the workbench and make sure the gate is never left unprotected (e.g. with a resistor/zener/TVS diode) somewhere where a user can "zap" it (e.g. via a connector). There are plenty of much more common components that are as easy if not easier to kill and are in common use by hobbyists, such as many of the "neopixel" smart LEDs, laser diodes, some CMOS chips ... Should we avoid all of these too?It is much better to learn this by frying a LED or an 2N7000 than a more expensive part, in my opinion.

author: Marco
author_rank: Super Contributor
timestamp: February 12, 2020, 08:27:27 pm
content: If there's Neopixel's with ICs without input protection you should definitely avoid them, there's no real excuse for that. Half century old CMOS ICs without input protection are curiosities you shouldn't be wasting on a practical circuit either. Junctions even of a laser diode aren't as vulnerable as a MOS gate, they can at least avalanche a little without damage.

author: cmrincon
author_rank: Newbie
timestamp: February 12, 2020, 10:11:08 pm
content: Hey! Check my new wear for manipulate mosfets

author: janoc
author_rank: Super Contributor
timestamp: February 12, 2020, 10:21:48 pm
content: Quote from: Marco on February 12, 2020, 08:27:27 pmI don't know whether or not the neopixels have input protection but they are certainly easy to kill.Even if there is some protection, it isn't foolproof - it is usually just a pair of diodes and with a sufficiently energetic zap you will kill them or cause a latch-up, potentially destroying the part. It is certainly not a replacement for even basic ESD precautions. ESD mats are cheap, humidifiers and/or plants as well.

author: Circlotron
author_rank: Super Contributor
timestamp: February 12, 2020, 11:04:46 pm
content: Quote from: janoc on February 11, 2020, 07:00:28 pmGood point. My example is I've bought several thousand "ST" M27C801 1Mx8 eproms from a particular supplier over the years. Upside is they are inexpensive, reliable, and only about 1 in 50 won't program fully. Downside is if you scrape off the paint there is some Chinese writing underneath so not made by ST in Singapore as per the outer layer, they take about 2 hours to fully erase and some won't even do that, and quoted access time is 100nS but in reality is closer to 1uS. But... they are reasonably consistent and quite good enough for my intended usage so I stick with them.I've bought a similar amount of SPW47N60C3 mosfets from the same supplier (TO-247 package) and early in the piece, when I would bend the leads at right angles they would crack and break off. Some were leaky and no functional, some even pressure sensitive in that they would stop working when they were clamped to a heatsink but come good when they were unclamped. Metal surface was all scratchy looking too, not shiny like a genuine one. Upside with these is when used well within their specs they were just fine. Some have been in daily use for 20 years now. Just been lucky I guess.

author: nigelwright7557
author_rank: Frequent Contributor
timestamp: February 13, 2020, 01:56:28 am
content: Chinese businesses are like most countries, some good and some bad.The problem is do you just trust your luck or buy from reputable dealers.I got caught out a few times with bad ebay components and now just buy from RS Components and Farnell components.In the last 10 years only had 1 problem with Farnell and they had put wrong resistor in the packet.The packet had what I wanted on it but resistor inside was wrong.

author: vk6zgo
author_rank: Super Contributor
timestamp: February 13, 2020, 02:32:34 am
content: Meanwhile, half century old CMOS gates have been working happily for, yes, half a century, in old equipment.Perhaps the "ancients" knew something you don't!

author: Circlotron
author_rank: Super Contributor
timestamp: February 13, 2020, 04:35:54 am
content: Quote from: vk6zgo on February 13, 2020, 02:32:34 amThe good ones have certainly been going all that time.The bad ones conked out and got replaced long ago.

author: DBecker
author_rank: Frequent Contributor
timestamp: February 13, 2020, 04:34:27 pm
content: Quote from: vk6zgo on February 13, 2020, 02:32:34 amNo, the original MOS chips were as fragile as you have heard *as unmounted components*. Once installed in the circuit they were much less likely to be destroyed.Pretty much every part today has ESD diodes or similar protection. Old CMOS didn't have the die area or process capability to do that. Plus there was much more process variation between wafers, leading to some being especially vulnerable. The especially weak ones died early, leaving only the robust ones.

author: jfiresto
author_rank: Frequent Contributor
timestamp: February 13, 2020, 05:10:10 pm
content: Quote from: DBecker on February 13, 2020, 04:34:27 pmWhat sort of old CMOS do you have in mind? Even the original 4000A-series logic found room for ESD networks. Without them, the chips would have probably been too fragile.

author: Psi
author_rank: Super Contributor
timestamp: February 14, 2020, 10:39:11 am
content: Quote from: wraper on February 11, 2020, 10:08:25 pmI'm only going on my experiences using aliexpress.i've encountered more fake parts (that cause actual problems) from pcbway PCBA runs than from aliexpress.The danger zone for fakes is parts that are specialized or a more expensive version of something common.Like an extra stable voltage regor a low noise opampor a low rds mosfetThe most common fakes i've run across are where they take a similar but much cheaper chip and restamp it to be a more expensive version. These sort of fakes are not caught so quickly because the circuit still works most of the time.

author: TheDane
author_rank: Regular Contributor
timestamp: February 14, 2020, 01:13:22 pm
content: Quote from: Psi on February 11, 2020, 09:55:21 pmHaving had only a few cases of issues vs.loads of great experiencesI can add this to your excellent list:Also:Doing some research - take a VERY close look at the pictures posted and compare to what is in the datasheet or google pictures - and you can avoid wasting your money.Buying from a seller which offers tons of other (non-related/electronics) stuff is also a potentially bad sign.If they offer a wide variety of related goods, imho they also tend to be more serious and has 'better' parts in general.Be kind, establish a long term relationship by re-ordering + don't bargain down the price - then ask the seller to look for component xyz at a trusted store/place.Be a, dispute any littlewhilst only grapping the cheapest offerings - and you might make it onto alist (Many store names, fewer shops, couple of shippers, one receiver)You get what you pay for, and you get treated as you treat others/'them'.Be a sceptic and do your own pre-research. Sure it takes a bit longer to order and be kind - but it takes a lot longer for the order to arrive, even longer to re-order.

author: wraper
author_rank: Unknown
timestamp: February 14, 2020, 01:40:52 pm
content: Quote from: TheDane on February 14, 2020, 01:13:22 pmin 90%+ of cases pictures do not show actual product you will receive. Picture may contain genuine item and you will receive counterfeit or vice versa.QuoteNope they still usually sell a lot of fake crap.

author: Ivan7enych
author_rank: Regular Contributor
timestamp: February 14, 2020, 03:01:53 pm
content: I've had opposite experience recently.5v regulator from ST-microelectronics 78L05 officially bought in russian supplyer has failed my project - by documentation it is rated up to 30v input, but on my board it fails at 28v input, burned itself and several other ICs.On the opposite, 78L05 from Ali with unknown marking "WS 78L05" works fine up to 35v input.

author: wraper
author_rank: Unknown
timestamp: February 14, 2020, 09:35:33 pm
content: Quote from: Ivan7enych on February 14, 2020, 03:01:53 pmOfficially bought from crappy supplier which applies to 100% of Russian suppliers to some extent. Whenever you'll buy parts, all have fake parts. Some are crappier than others though. For example you can buy something from Чип и Дип at ridiculously high price and get a fake crap.

author: janoc
author_rank: Super Contributor
timestamp: February 14, 2020, 09:45:46 pm
content: Quote from: Ivan7enych on February 14, 2020, 03:01:53 pmThat is most likely due to the poor design of your circuit and e.g. heat caused parameter drift/manufacturing tolerances than any poor quality parts. If you are using a part rated for 30V in a circuit where it can get 28V and then you are wondering that it has eventually failed (and blew up other things), you have only yourself to blame, IMO. Never heard about component derating? Operating any component right up to its absolute maximum ratings is a recipe for disaster.And why, for heaven's sake, are you running an 78L05 from 30V in the first place?! Even at the 5mA quiescent current you are going to dissipate around 125mW in that plastic package. Add any load and it gets much worse pretty quickly. That thing is going to be pretty toasty! Fortunately it has internal thermal protection, but it still makes one wonder what are you trying to achieve there with such setup.

author: jmelson
author_rank: Super Contributor
timestamp: February 14, 2020, 11:39:35 pm
content: Quote from: cmrincon on February 11, 2020, 09:21:30 amThese Chinese junk merchants are my absolute LAST place to get anything from. I only buy from franchised distributors except for obsolete parts where that's the only people who have them. Sometimes I need to repair an old product of mine, or make just one more board of an old design that uses an old part. Other than that, I just won't do it because of this sort of problem.You wanted a 2N7000, but got some kind of FET device, but who know what?Jon

author: Psi
author_rank: Super Contributor
timestamp: February 15, 2020, 12:27:33 pm
content: Quote from: TheDane on February 14, 2020, 01:13:22 pmAgreedIf the aliexpress seller has listings for 16bit DAC chips, door bells, handbags and bed sheets it's a good sign they don't really know what a 16bit DAC chip actually is. This means there is a extra high chance of mistakes in the technical listings/descriptions.They may have added keywords that are incorrect and make you think you're getting something you're not.And if they're that unfamiliar with the product they're more likely to buy fakes themselves without knowing.This is why it's usually better to order from a seller that is only selling electronic items.At least they're more likely to know something about what they are selling.It's always good to look for inconsistencies in a listing, If the photo implies one thing but the description says something else do not buy from that seller. Find someone selling the item that seems to know what they are talking about.When i'm looking for a seller to buy a particular item from i'm always looking for any reason to skip to the next, more expensive, seller.It usually goes something like...-Way to cheap. Next.- WTF. Why are they saying this mosfet has a Rds on of 10V. Next.- No specs listed, just a photo.. Hell no.- 91% feedback rating, Nope. Next.....- This looks ok. (Clicks buy)

author: Ivan7enych
author_rank: Regular Contributor
timestamp: February 15, 2020, 04:46:45 pm
content: Quote from: janoc on February 14, 2020, 09:45:46 pmMy circuit was designed for 24v input, current is 1mA (3 74hc chips), so my choice of 78L05 looked just fine. Derating was done, no overheating problems. But when input voltage was accidentialy rised above 28v (below 30v, still whithin specs of this regulator), this ST78L05 at first outputs 7V, then blows itself and killed all 74HC chips...

author: worsthorse
author_rank: Super Contributor
timestamp: February 15, 2020, 11:10:56 pm
content: If you can buy a part for eighty cents that currently is sold by digikey for twelve dollars, there's only a few reasons for that price differential: it is a degraded copy, remarked fake, reject, or stolen. There is just no other way to account for such price differences, at least for distributor stocked parts. The same goes, generally, for NOS parts, especially NOS parts that weren't heavily stocked in the day outside of the United States or Europe. Just ask yourself, why would there be a big stock of forty year old NVRAMs sitting in some warehouse in China or Vietnam? Can you find NOS parts? Yes, and I often do, but invariably they are from individual sellers getting rid of personal stock or well established vendors that sell little else.I guess it depends on how you want to spend your time and money. Personally, I hate trying to track down circuit problems caused by marginal components, even when building throwaway circuits. And I don't want to have test every part that I buy to figure out if it is what it says it is on the label before I can use it.So I've never found the money saved buying really cheap parts to be cost or time effective, whatever vetting process one uses to find a "reliable" vendor.

author: janoc
author_rank: Super Contributor
timestamp: February 15, 2020, 11:24:09 pm
content: Quote from: Ivan7enych on February 15, 2020, 04:46:45 pmThat looks like you got unlucky with a dud part. However, with such high input voltage I would rather use a switching regulator instead of having such a large drop over a tiny linear regulator. If you add the quiescent current of the regulator to your load current, that's quite a bit of power being dissipated.At least I would pick something with a higher input voltage rating, e.g. LM2936M (40V) or TPS79850QDGNRQ1 (50V). 30V rated part for a 24V input is a bit close for comfort, IMO.

author: wraper
author_rank: Unknown
timestamp: February 16, 2020, 04:33:36 am
content: Quote from: janoc on February 15, 2020, 11:24:09 pmThere is little point going with switcher at 1mA load. Quite likely you will have higher quiescent current than 78L05.

author: KE5FX
author_rank: Super Contributor
timestamp: February 16, 2020, 04:52:42 am
content: Usual cause of 78xx regulator failures is having too much capacitance on the output side. If the input rail falls faster than the output rail, perhaps because the input is feeding other loads, the capacitance at the output will backfeed the part and cook it. This happens at turn-off time, of course, so the next time you turn it on, your "regulator" will send the full input voltage downstream.Designing those parts without an internal diode was nothing short of irresponsible, but it is what it is. Most 3-terminal regulators have the same hazard, and most of the time it's discussed in the data sheet, but not always.

author: nigelwright7557
author_rank: Frequent Contributor
timestamp: February 16, 2020, 08:21:43 pm
content: Quote from: cmrincon on February 11, 2020, 09:21:30 amThere are good and bad suppliers in most countries not just China.The trick is finding reputable dealers.I only use Farnell and RS Components and have very few problems.

author: Red Squirrel
author_rank: Super Contributor
timestamp: February 17, 2020, 04:02:29 am
content: Genuine parts on Digikey and similar legit stores are not even all that expensive when all thinks considered so I feel it's not even worth buying the cheap chinese stuff. I mean yeah even the genuine ones are going to be made in China but I imagine they go through a bit more testing and scrutiny, right? I think it's incredible that as individuals we even have access to raw electronic parts and that it's not just big companies.I have bought cheap parts off Amazon to pad orders to get free shipping though, but I tend to stick to passives like resistors and capacitors. I would not buy stuff like microcontrollers or even transistors as trying to troubleshoot some weird unpredictable issue as a beginner and not understanding why it's behaving that way could be frustrating as I may not even realize something is wrong with the part and think it's me doing something wrong.

author: Psi
author_rank: Super Contributor
timestamp: February 17, 2020, 11:18:57 pm
content: Quote from: Red Squirrel on February 17, 2020, 04:02:29 amFor 1 off hobby stuff yes, known good chips from digikey are still cheap and affordable. Most things are less than buying a cup of coffee.But when you are ordering 500 for your home manufacturing business you look at $2 each for a SMT piezo buzzer on digikey, then you look at $3 for 10 on Aliexpress.Assuming you're happy that the aliexpress piezo quality is good enough, and that piezo failures in the product don't matter much anyway.Then going with aliexpress is a no-brainer, it's a saving of $850

author: wraper
author_rank: Unknown
timestamp: February 18, 2020, 11:43:04 am
content: Quote from: Psi on February 17, 2020, 11:18:57 pmThen going to aliexpress is face-palmer. It will bite your ass and saves nothing in comparison with reliable options like LCSC. I've tried several times ordering more of stuff at Aliexpress in the past. Then you get 200 crystals 5-10% of which are faulty. Or AVR MCUs which are re-marked old stock which solder like crap, etc. And when you need to test and rework that with that in scale of hundreds of items, it becomes hell.Not to say even compared to Digikey, price advantage at higher quantity diminishes. Unless you are buying fake crap. Also you don't need to buy at Digikey. There is Mouser, Farnell, TME and others which usually have lower prices.

author: Psi
author_rank: Super Contributor
timestamp: February 18, 2020, 11:50:48 am
content: Buying crystals from aliexpress sounds like a terrible idea.As i said before, choose your battles.

author: wraper
author_rank: Unknown
timestamp: February 18, 2020, 12:25:44 pm
content: Quote from: Psi on February 18, 2020, 11:50:48 amAnd why do you think buzzers will be any different? Also SMT piezo buzzer is not nearly $2 at digikey unless you want to go for expensive option. And here you go, almost as cheap as your $3 for 10 and has datasheet (BTW there are actually none on aliexpress that match your description)https://lcsc.com/product-detail/Buzzers_KELIKING-KLJ-1625_C201041.html

author: Psi
author_rank: Super Contributor
timestamp: February 19, 2020, 12:24:39 pm
content: Quote from: wraper on February 18, 2020, 12:25:44 pmMainly because crystal are a precision part. If the frequency/stability is off your product may have serious problems.but if the piezo beeper frequency is a little off, or a little quieter than normal, it's not usually a problem.If a crystal fails your product stops dead, if a beeper fails your product just doesn't beep any more.The piezo beeper was just an example i ran into 3 years agoThis was the style/footprint of the buzzer i was orderinghttps://www.digikey.com/product-detail/en/murata-electronics/PKLCS1212E40A1-R1/490-5262-1-ND/1992371I dont think LCSC exited back then, or if it did i didnt know about it.

author: wraper
author_rank: Unknown
timestamp: February 19, 2020, 12:30:15 pm
content: Quote from: Psi on February 19, 2020, 12:24:39 pmFrequency stability was not a problem. They were mechanically damaged internally. Conductive adhesive between crystal and package broke.

author: nigelwright7557
author_rank: Frequent Contributor
timestamp: March 12, 2020, 12:42:14 pm
content: "Save a penny, lose a pound""Buy cheap, buy twice"etc etcLearned my lesson years ago with ebay and/or Chinese parts.Always buy from Farnell or RS Components now.

author: ratatax
author_rank: Regular Contributor
timestamp: March 22, 2020, 06:07:38 pm
content: Generally only use Aliexpress to get generic stuff and chinese-branded products and you're fine. I've had more problems with sellers sending the wrong item than counterfeit parts.It's not a good idea to search for well known brands as it's too much tempting for sellers to make money this way.The only branded stuff I bought on Ali was a box of 150 raspberry Pi's for like $5k, everything went fine but I checked it was an approved official retailer and with highly positive feedback

author: Psi
author_rank: Super Contributor
timestamp: March 23, 2020, 09:08:57 am
content: Quote from: ratatax on March 22, 2020, 06:07:38 pmSame.

author: bd139
author_rank: Super Contributor
timestamp: March 23, 2020, 09:21:19 am
content: Quote from: Psi on February 18, 2020, 11:50:48 amI bought a ton (at least 800 from 20-30 different batches) of crystals from Aliexpress and tested the vast majority of them properly i.e. motional parameter testing. They have been 100% problem free. The only issue you are likely to get is that the normal distribution of the frequency isn't specified down to ppm and the load capacitance isn't specified like some manufacturers but you can trim that out as you would if you needed an accurate in circuit crystal. They are absolutely fine for MCU clocks if you don't have precise long-term timing requirements which is what they are designed for. I managed to bastardise them into some pretty excellent crystal filters.Interestingly the 100MHz no brand 5th overtone ones I bought for $3 were better than the commercial one I paid $30 to have made.The trick with Aliexpress is know what the risks are and buy accordingly. For me that's don't buy anything that might kill you. The rest is fair game. The only risk is waiting because if it's a turd, meh you've lost $1 or so.

author: nigelwright7557
author_rank: Frequent Contributor
timestamp: June 02, 2020, 01:29:15 pm
content: I have found some Chinese stuff is ok and some not.My stance now is not to buy semiconductors but passives seem to be generally ok.I ordered some 0.2" pitch capacitors off Ali Express and when they came they were 0.3" so didnt fit my pcb !So on my next pcb made the pitch 0.3".When I ran out of caps I bought some more more 0.3" and when they came they were 0.2" !!!!!I think someone needs to sell the Chinese a ruler.I complained about the narrow caps and was told to ask a "proper" engineer about them and could I not force fit them !In the end Ali Express butted in and refunded me.I bought some mosfets off Ali Express for an amplifier. It powered up fine but when I unplugged my soldering iron it blew up.The glitch down the mains must have got in to the amp power supply and pushed the mosfets into breakdown.So this time I bought some from RS Components and the yare still working (despite me trying hard to blow them) for 18 months.The Chinese have a habit of cutting corners and use smaller dies than the original which messes with parameters.

author: Quarlo Klobrigney
author_rank: Super Contributor
timestamp: June 02, 2020, 02:11:54 pm
content: I bought some 25 or so 100 qty packs of 1% resistors last year. 50% of the 25 packs were 20% off value, in other words, the 100K pack ok, 1M pack 20% off tolerance. And so on. I had to verify the error to Alibaba with a picture of the defective resistors, one by one per pack value with the accompanying Fluke LCD screen before I was granted a refund.On another order that came up short, Phoenix connectors at 20 pieces were at 14 pieces. I had to show a picture of a bag with only 14 in it and the label of 20.Now how does one send a picture of completely missing goods. I'd like to know.

author: bd139
author_rank: Super Contributor
timestamp: June 02, 2020, 02:26:35 pm
content: I just charge backed aliexpress when they did that with the "prove it never arrived" and they blocked my accountFuck 'em!

author: SilverSolder
author_rank: Super Contributor
timestamp: June 02, 2020, 02:31:52 pm
content: Quote from: Quarlo Klobrigney on June 02, 2020, 02:11:54 pmThat problem is what "Tracking" is supposed to solve? - mind you, it doesn't always. Sometimes the post office messes up the delivery, it gets marked as "Delivered" but ends up at someone else's house...

author: GavinHemmings
author_rank: Newbie
timestamp: June 03, 2020, 10:46:41 am
content: I have a lot of products from aliexpress and I have no problems with this.

author: wraper
author_rank: Unknown
timestamp: June 03, 2020, 10:56:04 am
content: Quote from: GavinHemmings on June 03, 2020, 10:46:41 amThen you are either very lucky or simply clueless about what you got.

author: wraper
author_rank: Unknown
timestamp: June 03, 2020, 11:01:56 am
content: Quote from: blueskull on February 19, 2020, 12:34:55 pmThey were not THAT cheap. And I can buy similar crystals from LCSC for 30% of the price I bought those for.

author: Koen
author_rank: Frequent Contributor
timestamp: June 03, 2020, 11:13:18 am
content: 12 years on Alibaba, about 10kEUR / year, zero issues, very happy overall. Just got my first bait and switch :https://www.eevblog.com/forum/manufacture/tewaycell-li-polymer-batteries-scam-bait-and-switch/

author: nigelwright7557
author_rank: Frequent Contributor
timestamp: August 30, 2020, 02:33:50 am
content: Got 2 AD9220 a2d converters from Analogue Devices.Bought 2 from Ali Express.First pcb I used an AD device and got it working fine.As an experiment I tried the Chinese device and couldnt get full speed out of it without lots of data noise.I should know better by now than to risk Chinese parts.

author: Edward3121
author_rank: Contributor
timestamp: August 30, 2020, 03:29:38 am
content: 这样的元件并不适合在阿里巴巴（aliexpress）或者ebay上购买。因为这两个网站上的卖家鱼龙混杂。从这里买到的元件可能是“能工作”或者“可以用”的，但是长期使用或者用于极限情况时候会出问题；当然也会有很大几率买到不能用的器件。因为卖家为了利益，卖的元件是假冒的、翻新的、打磨的、甚至是工厂筛选下来的废料重新包装的。但是这不代表中国器件（chinise parts）是不行的，只是没买到好的而已。提供一些建议（我自己的经验）：1.在阿里巴巴（aliexpress）或者ebay买元件（包括有源和无源器件），要有一定心理准备，因为可能有无法工作的。2.经过自己尝试或者朋友推荐，确定一些比较可靠的卖家，尽量在这些卖家中买。3.如果一定要在阿里巴巴（aliexpress）或者ebay买元件，而且是芯片类型的，不要相信所谓“全新”、“散新”、“原装”这样的字样，很多都是假冒的或者是翻新的。要买“原装拆机”的，也就是从旧的PCB上拆下的，没有经过其他处理的，这样能保证是真品。4.建议去元器件零售商购买元件，比如贸泽电子、digikey、深圳立创商城（SZLCSC，中国）等等，价格会略高一些，但是能够保证品质。顺便说一下，深圳立创商城（SZLCSC）有很多中国产的（chinise parts）器件，质量也是有保障的，价格也很实惠。

author: VK3DRB
author_rank: Super Contributor
timestamp: August 30, 2020, 08:44:37 am
content: A client commissioned a contract manufacturer in China to make a device I had been developing. Part of the device has two brand-name 100k 0.1% 0402 resistors used as a voltage divider from a precision 2.500V voltage source down to 1.250V used as a voltage reference. They built 100 prototypes of the boards, but there were about 10 failing boards with the same error in firmware - some failing straight away and others failing after a after a few weeks of testing. Found out the cause of the error: Some of the 100K resistors were out by up to 1%, with one measuring 97k... 3% low! The values were all over the shop.The manufacturer's excuse was they might have had the temperature profile on their reflow oven set a little too high. I suspect this is complete and utterand it is more likely the manufacturer just had used cheapo generic resistors from the likes that you would see on eBay, AliExpress or a back alleyway behind the Shenzhen market for "a-dime-a-dozen". Even 1% resistors would not have that amount of variance from the same reel. I have never seen resistors going low with too much heat. Going high with excess heat - maybe - but there were no other issues on these boards that were quite complicated with many parts including BGAs.

author: SilverSolder
author_rank: Super Contributor
timestamp: August 31, 2020, 04:02:51 am
content: Quote from: Quarlo Klobrigney on June 02, 2020, 02:11:54 pmTake a picture of your empty mailbox!

author: nigelwright7557
author_rank: Frequent Contributor
timestamp: August 31, 2020, 04:17:59 am
content: Quote from: nigelwright7557 on March 12, 2020, 12:42:14 pmJust out of interest I bought a couple of cheap AD9220 a2d converters off Ali Express.I also got a couple of samples from Analogue Devices the manufacturer.The AD genuine one worked ok upto 10MHz.The fake part struggle from about 8MHz and was very noisy.So it seems I dont even take my own advice !

author: Psi
author_rank: Super Contributor
timestamp: August 31, 2020, 04:26:35 am
content: Best advice for Aliexpress,- Order by price- Ignore the bottom 25%That will cut out a lot of junk which is too good to be true.

author: BravoV
author_rank: Super Contributor
timestamp: August 31, 2020, 04:28:29 am
content: Really boring reading this kinda whines everytimes ... a typical noob online shopper.Its like a noob, who bought a brand new iPhone for 10 bucksin the alley with shady guy, and then whines alot that got cheated.Worst, and then cursed and accused the people who live in the whole neighborhood or the whole block are cheater and evil.

author: BravoV
author_rank: Super Contributor
timestamp: August 31, 2020, 04:41:26 am
content: Quote from: nigelwright7557 on August 31, 2020, 04:17:59 amAs the old saying, fool me once shame on you, fool me twice ... what a moron am I.Sometimes you just can NOT fix stupidity, even your own.

author: dietert1
author_rank: Super Contributor
timestamp: August 31, 2020, 05:29:01 am
content: Why somebody needs to buy parts really cheap? Probably because there is a lack of income. Maybe the reason for the lack of income is using unqualified parts in the past and spending to much time on fixes.I mean there are people who started this as a student (when their work could not yet generate income) and missed to change their habits later. It's not your work to shave off some pence from a BOM or is it? I am trying to do my work instead.Regards, Dieter

author: wraper
author_rank: Unknown
timestamp: August 31, 2020, 08:09:40 am
content: Quote from: dietert1 on August 31, 2020, 05:29:01 amProbably because someone is a cheapskate. I doubt that many of US or western EU residents are so poor and need so many parts that they need to buy 20 NE555 for $1.5.QuoteThis should be closer to reality. However many people simply like to buy cheap as possible even if they always had the money.

author: brabus
author_rank: Frequent Contributor
timestamp: August 31, 2020, 08:20:58 am
content: This is a shock for me. I genuinely thought the buyers of Aliexpress/eBay were 100.0% hobbysts.If a professional buys parts (single components, not semi-finished products) from Aliexpress/eBay for job related development activities, well... we have a whole lot to discuss here about the definition of "professional". I mean, the cost of the risk alone, computed by the time you wait for the shipment, makes zero economical sense.The real cost of the items is way higher than the price tag.I bought tons of stuff from eBay/AliExpress, got my good parts and bad parts, good shipments and bad shipments, but always got thevalueI paid for.On the other hand I had major issues with Mouser/Digikey as well, but the cost of those issues had already been taken into account in the project. The extra price you pay is compensated by the quick shipping and the prompt support you get from them: unthinkable with eBay/Ali.

author: BravoV
author_rank: Super Contributor
timestamp: August 31, 2020, 09:07:01 am
content: Quote from: wraper on August 31, 2020, 08:09:40 amHmmm ... 555 chip, coincidentally, my experience even though not $1.5, maybe it was about $10 for a bunch about 30-50 pcs of CMOS version of 555 (TLC555), don't remember well as it was many-many years ago purchased from AE shop.At that time, I was really prepared to receive fake 555 (non cmos version) as they're so cheap, but ended up all being genuine as I rigged up simple oscillator test circuit on breadboard below, and all run and still oscillated at 1.5v VDD, clearly not bipolar version, maybe luck was on me.

author: wraper
author_rank: Unknown
timestamp: August 31, 2020, 10:09:08 am
content: Quote from: BravoV on August 31, 2020, 09:07:01 amThere are many flavors of counterfeit 555. Them working without detailed testing/inspection proves nothing about them being genuine.

author: SilverSolder
author_rank: Super Contributor
timestamp: August 31, 2020, 12:31:02 pm
content: My philosophy is: if a part works well enough for my purposes, it is genuine enough!

author: bd139
author_rank: Super Contributor
timestamp: August 31, 2020, 12:32:27 pm
content: Same.Talking of which just ordered some hooky MAV-11 MMICs

author: wraper
author_rank: Unknown
timestamp: August 31, 2020, 01:08:42 pm
content: Quote from: SilverSolder on August 31, 2020, 12:31:02 pmUntil it bites you in ass and causes monetary loses exceeding component price 1000+ fold.

author: dietert1
author_rank: Super Contributor
timestamp: August 31, 2020, 01:27:22 pm
content: Building a test setup for checking 555s is a total loss for a professional EE. Even worse if you need to check every single part.I remember buying a minimal ADS1256 board from amazon to do some test. This was about € 40. It took me more than an hour to remove problems i found by visual inspection, lucky enough before applying power. Discarding faulty boards at amazon. Wrote a negative report at amazon. The offer disappeared, yet now the identical board is offered by somebody else for € 121. Won't buy, though.Regards, DieterPS: The € 120 offer is for three pieces, so they can't setup a new offer for each unit sold but for each three sold units.

author: SilverSolder
author_rank: Super Contributor
timestamp: August 31, 2020, 03:40:01 pm
content: Quote from: wraper on August 31, 2020, 01:08:42 pmIn which case - it would not work well enough for my purposes!There is a difference between taking calculated risks and being reckless.

author: wraper
author_rank: Unknown
timestamp: September 02, 2020, 02:22:54 pm
content: Quote from: SilverSolder on August 31, 2020, 03:40:01 pmSaying if it works for you = genuine enough is already reckless to begin with. Nowhere near to calculated risks.

author: SilverSolder
author_rank: Super Contributor
timestamp: September 02, 2020, 05:02:54 pm
content: Quote from: wraper on September 02, 2020, 02:22:54 pmI'm curious why you would think that is reckless, without knowing what I think "works for me" actually means.Let's take an extreme example: what if I am using a transformer as a door stop in my office, just because I think it looks cool. Would you consider it reckless to use a reconditioned, reclaimed transformer of unknown origin for that purpose?

author: wraper
author_rank: Unknown
timestamp: September 02, 2020, 05:54:03 pm
content: Quote from: SilverSolder on September 02, 2020, 05:02:54 pmReckless is when you use 5 tonne crane to hold 10 tonne weight. It might work for a while before some tragic accident happens. Which often happens with counterfeit transistors, diodes, voltage regulators, capacitors. When internals are significantly weaker in some aspect (voltage, current...) than marking suggests. Not to say that cheaper genuine parts from Chinese brands provide way more predictable results than more expensive parts with unknown internals.

author: Bassman59
author_rank: Super Contributor
timestamp: September 02, 2020, 06:05:37 pm
content: Quote from: dietert1 on August 31, 2020, 05:29:01 amThere is an observation here: "It's very expensive to be poor." This manifests in many ways, some of which might be non-obvious.For example, if you're poor, you might not be able to go see the doctor for something easily treated. Or, even if you do, because you're poor (and in the US the poor generally don't have health insurance), the doctor might write a prescription that won't get filled because the medicine costs $100 and you have to choose between meals or the medicine. And as a result, without treatment, the condition becomes grave, and you end up in the emergency room. Now the $100 medicine and the $100 doctor's office visit look cheap compared to a $50,000 hospital bill.Another example. You're poor, and you have a low-paying job (but you have a job) and you need a car to get to work. But you can afford only a junker car, which is unreliable, as opposed to a new car. And some days the junk car won't start so you miss a day of work. And if you miss enough days, you're fired.I could continue but you see the point.Now in this situation of being the poor college student who can only afford parts from Ali Express instead of DigiKey or Mouser, it's the same thing. You buy the Ali parts and hope that you chose a good vendor who won't fuck you and maybe you'll be able to build your project without spending endless hours trying to figure out why it fails. Or you could spend more and buy the parts from DK/Mouser and know they'll work and you can spend your time debugging your design rather than finding bad parts.

author: SilverSolder
author_rank: Super Contributor
timestamp: September 02, 2020, 08:58:12 pm
content: Quote from: wraper on September 02, 2020, 05:54:03 pmAgree 100%. But using a cheap transistor in a non-critical hobby circuit in your basement... hardly reckless, and possibly a learning opportunity?

author: Quarlo Klobrigney
author_rank: Super Contributor
timestamp: September 02, 2020, 09:02:01 pm
content: Unless the experimental device it's in, fails in such a way that tears a hole in the fabric of space-time.

author: chickenHeadKnob
author_rank: Super Contributor
timestamp: September 03, 2020, 08:02:21 am
content: Quote from: SilverSolder on September 02, 2020, 08:58:12 pmWraper is correct even for the case of the young student tinkering in his basement. Not because of safety or any professional type risk but rather it is highly demotivational to have your project fail for mysterious reasons when you are just starting out. They will think did I goof up? is my circuit bad ?, etcetera . Leading some students to give up early in frustration. Experienced people have far better awareness and debugging skills so they detect the bad part quickly and move on,In my teenage years I wanted to learn all I could about computers, both the programming side and hardware. This was during the 1970's so no internets, no online datasheets, no digikey/mouser/ebay, and no arduino. My options consisted of going to the engineering library of one university 80kms away round trip to get photocopies out of the few data books they had and buying parts from radio shack from the limited selection they had. There was also one hobby electronics magazine Electronics Today International edition that I followed, and I went to a second university 40 kms away to steal mainframe timeNo one I knew had my perseverance or auto-didactic drive to learn electronics and computing so by the time I reached the University level it was easy for me to obtain teaching assistant jobs in digital electronic lab classes. These consisted of helping the'tardsstudents make basic circuits from 74 series parts and some pre-built modules. They would be stymied by the simplest of problems. Bent pin under chip because of ham-fisted insertion into breadboard, crap wiring, reversed power or no power connected. They also couldn't discern when the problem was simple connection error or if the chip was bad because the previous retard had destroyed it. Things which would hardly have slowed me down when I was a teen by myself would cause them to give up right away.The situation with analog components is even worse as a bad but functioning part can depart from the expected datasheet in very subtle ways.

author: SilverSolder
author_rank: Super Contributor
timestamp: September 03, 2020, 01:27:48 pm
content: Quote from: chickenHeadKnob on September 03, 2020, 08:02:21 amOK, that's a fair point. I would also add that most of the time, components are cheap enough that we can buy new, high quality stuff and should not be tempted into the dark side.But that still leaves the situation where an experienced person buys cheap parts that he/she is familiar with, in the full knowledge that these are not prime parts... in return for paying a lot less for them.It is similar to buying a used car, or a "cheap brand" car, in my view. If you are buying an old junker that has been repaired by dozens of people, with banana skins in the gearbox and differential to keep them quiet, you do not have the same expectations that you do when buying a brand new car - and you don't expect to pay new car prices, in return for that. You can also choose a cheaper brand of car. You might have different expectations from a BMW compared to a Perouda, for example. Does that make the Perouda buyer, or the used car buyer, a reckless person? It all depends what their expectations or requirements are!Why wouldn't the same principle apply with electronic components?

author: wraper
author_rank: Unknown
timestamp: September 03, 2020, 01:58:12 pm
content: Quote from: SilverSolder on September 03, 2020, 01:27:48 pmExperienced person saves money by buying parts of lesser known Chinese brands. Buying on aliexpress/ebay is a valid option only for some sorts of parts, say you want to buy a Richetek PWM controller to repair a graphics card. Hard to obtain otherwise and chance of counterfeiting is very low. Otherwise it's like searching in a pit full of crap in hope of finding gold. You may find it, but in the process you will be covered in shit from top to bottom.

author: SilverSolder
author_rank: Super Contributor
timestamp: September 03, 2020, 02:19:00 pm
content: Quote from: wraper on September 03, 2020, 01:58:12 pmI guess another thing we are not mentioning is that you have to be experienced not just with electronics per se, but also with buying stuff via the various Internet shopping sites in general.After years of experience buying smelly stuff, you develop a "sixth sense" as a buyer and then the percentage of crap you end up with drops to quite acceptable levels.

author: wraper
author_rank: Unknown
timestamp: September 03, 2020, 02:30:29 pm
content: Quote from: blueskull on September 03, 2020, 02:08:29 pmI received relabeled nvidia GPUs, one part number sold as another. Same silicon physically but config is not. Got one Toshiba stepper driver relabeled as another. Found out by measuring pins, if I didn't do so, I would have explosion and probably burnt traces in my device. Got relabeled UV EPROMs, 25V part relabeled as 12.5V. Got mix of attiny24 and 24A blacktopped and relabeled as 24A with a fresh date code, terminals soldered like shit. Those were not insanely cheap. For components which could be obtained from normal distributors it was the same or a little bit lower price than you would expect from Mouser or similar at qty of 100-1000.

author: wraper
author_rank: Unknown
timestamp: September 03, 2020, 02:43:19 pm
content: Also once AD8293G160 was out of stock everywhere and I needed them urgently. Ordered few hundred from aliexpress at the price which was even higher than from distro. They were new and genuine but defect rate was like 20-25% with various issues, especially at one end of the tape where it was worse than 50%. I suspect it was some serious ESD. It was not popcorning due to moisture since they were bad even with hand soldering.

author: asmi
author_rank: Super Contributor
timestamp: September 03, 2020, 04:34:57 pm
content: Quote from: blueskull on September 03, 2020, 02:36:00 pmI once got incorrect chip (wrong P/N) on Aliexpress, and through dispute demanded refund without return because the latter is not economical, Aliexpress agreed with me and refunded the full amount.

author: wraper
author_rank: Unknown
timestamp: September 03, 2020, 04:48:38 pm
content: Quote from: blueskull on September 03, 2020, 02:36:00 pmIf you find out in time. Those attiny were made quite convincing. Unfortunately I did not compare of date/lot code on top and bottom as they should match (they did not). Found out only during testing after they were placed on 100-ish of boards. More than half of the boards consumed like 2mA more than normal, other consumed as they should. When I checked date code on the backside, it became clear that those which consumed more were made before 24A was even released.Stepper drivers sat in my drawer a few years before I decided to actually use them.

author: bd139
author_rank: Super Contributor
timestamp: September 03, 2020, 05:10:08 pm
content: Quote from: asmi on September 03, 2020, 04:34:57 pmYeah same here. I’ve had broken stuff and fake stuff and aliexpress always sides with the buyer if you get them involved.

author: PlainName
author_rank: Super Contributor
timestamp: September 03, 2020, 06:00:31 pm
content: QuoteOne learns something new every day!

author: thm_w
author_rank: Super Contributor
timestamp: September 03, 2020, 08:10:43 pm
content: Quote from: wraper on September 03, 2020, 04:48:38 pmI think most people here are building one or two boards. Anyone populating 100s of boards with parts from alix without thoroughly testing a few first is a bit reckless IMO.Quote from: blueskull on September 03, 2020, 02:08:29 pmBought these and they were both fake, but that was to be expected (unobtanium part for pennies):https://item.taobao.com/item.htm?id=35631303299https://item.taobao.com/item.htm?id=544364491832Some other regulator that can't handle ~30V.

author: wraper
author_rank: Unknown
timestamp: September 03, 2020, 08:17:46 pm
content: Quote from: thm_w on September 03, 2020, 08:10:43 pmThey were inspected under microscope upon receiving and a few tested. It's obvious all of them were working. I didn't know at that moment that Atmel prints date code on the back so did not focus on that. As I said, they were made pretty convincing.

author: ozcar
author_rank: Frequent Contributor
timestamp: September 03, 2020, 10:31:56 pm
content: Around two years ago I bought 10 x LM311P from a Chinese seller on Ebay. Only got around to trying to use one something like 6 months later, and found that none of them worked. I turned up an old thread here dating back to September 2015 (https://www.eevblog.com/forum/chat/fake-andor-mislabelled-lm311-)/ ), where somebody reported receiving what appeared to be LM358 marked as LM311. I checked the ones I had, and they too could have been LM358.I was surprised by this. An LM358 (dual opamp) has no chance of working as an LM311 (single comparator with OC/OE output). Why bother to have any chip at all inside? And what is particularly attractive about doing this, that it had been happening for at least three years at the time?Fast forward to the present. About a week ago I ordered 5 x LM311P from a local (Australian) seller - one with "good" prices, but not "ridiculously cheap". I received them only two days ago, and although the marking on them is slightly different to the dodgy ones I got before, these too appear to be mislabelled dual opamps.I put in a return request yesterday, explaining the problem, and within 15 minutes I received a refund, but without any explanation. I see that the listing I purchased from is still up on Ebay, but items not currently available for purchase as it has been flagged "seller is away". None of their other listings has been flagged like that. The jury here has still to decide what this particular seller knew.

author: Bud
author_rank: Super Contributor
timestamp: September 03, 2020, 10:52:41 pm
content: Buy from an industrial supplier and save yourself time and frustration. When you people will get that

author: dietert1
author_rank: Super Contributor
timestamp: September 04, 2020, 03:16:08 pm
content: And how will you proceed? The refund will by you 1.4 samples from mouser. Can't you get some free samples from Infineon?Regards, Dieter

author: SilverSolder
author_rank: Super Contributor
timestamp: September 04, 2020, 05:08:32 pm
content: Quote from: dunkemhigh on September 03, 2020, 06:00:31 pmNote, it only works for the duration of the test drive! (Sawdust may last slightly longer!)

author: nigelwright7557
author_rank: Frequent Contributor
timestamp: October 12, 2020, 03:28:08 pm
content: I bought in some Chinese solder for doing small pitch SMD 0.5mmWhat a disaster it just barely melted and great blobs everywhere !So bought some from RS Components and it worked great first time.I have mixed experiences with Chinese vendors. Great pcb manufacture but some of the semiconductors blow up if you fart near them.