I agree for special and more expensive parts. I only tested very cheap standard transistors where I even cannot believe there would be enough bad production runs. It could be that they are relabeled. In this case i think I would have discovered it.

@@AndreasSpiess Common way how fake parts are created is by relabeling a lower spec part as a more expensive higher spec one. Or a Chinese clone with slightly different specs gets relabeled/sold as the genuine part. Your test won't really catch that, only the gross fakes (a totally wrong part relabeled). This is common for both opamps, power transistors and even electrolytic capacitors. On the other hand, if your project isn't critical (most hobbyist stuff), it likely won't matter much as long as the part does what it is supposed to and you don't need the limit parameters (i.e. low noise precision/audio opamps, large current mosfets or power transistors for an amplifier/switching supply). For professional application (= something you are going to sell) you would be a fool to buy components from AliExpress or eBay, though. That said, even in Asia it is not a problem to buy genuine parts - e.g. LCSC or other reputable sellers will not sell you relabeled fakes.

Your theory is easily refuted. There is a large relabelling business in China. Often they just freshen up genuine salvaged parts to make them more presentable and easier to use in manufacturing, they straighten and refinish the legs, and they grind down the label side and repaint and relabel it. Obviously nobody will produce a new IC specifically for a fake, but for many categories of semiconductor products, you will find a lot of possible substitutes. 7406 is a generic part. Soviet Union started making one in the 70s designated K155LN3, and everyone else has one too, if Soviet Union had one, means China had one too going all the way back. There are literally dozens of different die designs (unlicensed) for the whole 40 and 74 series chips with same pinout and function, but different electrical spec. As far as MOSFETs go, you can do a quick check for gate capacitance, for fake ones it's usually not even in the same order of magnitude as the genuine part, so they have a completely different die design. Often enclosure differences are seen, and when they are decapped, a die of different (usually smaller) size is found inside. You will also find that whenever there is a REALLY popular part, whether Western or Japanese, you will find that someone spins up a part in China as a substitute to allow device manufacturers to reduce costs. I could give you a million example but i'll start with just one, the STM32F103 processor has been "cloned" by two different manufacturers, GigaDevice as GD32 series and CKS as CS32 series. They are not direct clones - they are compatible processors with same pinout, similar and largely compatible peripherals, and ARM licensed identical core, but they show behavioural differences and manufacturing process differences. So far so good, this is completely legal and valid. But then you'll find processors in the wild that are marked STM32 and vaguely made to look genuine, but are definitely not, and are instead actually these compatible replacements, see Alex Kenis for proof, and i think i might have one of those too in my pile of parts. And mind you, these CS32 and GD32 chips definitely cost a bloody FORTUNE to spin up, because they've got everything: high-density processor, flash, mixed-signal for comparators and ADCs, power semiconductors for the internal linear regulator, RC oscillators, they have just about every engineering complication you can think of, and yet it evidently made sense to build them. For some parts, it's certainly the case that there exists no fake die and every device is genuine, but often cosmetically manipulated. Some single devices are extremely likely to be fakes. The ratio of fakes varies depending on viability, and many reputable Aliexpress sellers are pretty good at dodging fakes for the most part.

I can explain how some of the genuine parts can be so cheap. Water absorption. SMD packages need to be dry for the soldering ovens or they can crack, so components have to be dry. They arrive sealed, but will start taking in moisture the moment they are opened. Depending on the component packaging (and climate) you could have from a day to a couple of weeks to use them. After that they're just no good for industrial soldering ovens. However, they're perfectly ok for hand soldering. They can be dried out, but it's usually just not worth it for the companies, so they go in the scrap bin (and get "recycled"). Skip diving and part recycling is an industry in itself in China. I would salute their green credentials if it wasn't done purely for money and their other industries weren't so polluting!

I would say inappropriate ESD + MSL precautions during handling, shipping and experimentation/installation is what creates a lot of issues. Want to pay for proper handling and care? - you do pay a higher initial price, and (hopefully) avoid a lot of issues and problems down the line if you do your part right. Want to gamble - buy from an unknown source, some are legit and honest - you (hopefully) win. Others aren't, and you (certainly) loose. This is my experience, not a theory.

It is a good concept also for other areas...

It is also much faster with digikey (or similar). Even in Australia if I order a half reel of transistors it takes 4 days. My last order was made on a tuesday and delivered on the next monday.

Why would you buy single transistors? Buy a set of 25-50 of each for the $36-50 it costs and never worry about not having a fitting part. I only order from 4.8+ rating suppliers and have never had a serious problem. Any time something has been broken they refunded my money and let me keep the item. I paid 3.50 for 20 transistors from a store here and could have gotten 180 on aliexpress for the same price. For many products you can buy directly from the manufacturer on Aliexpress and save a lot of money. Voltcraft for instance sells rebaged Hantek stuff for crazy prices. My MSO5202 would have cost over 800 Euros and it sells for ~480 from Hantek. I paid 285 because I had ordered the DSO4102C but the seller sent me the more expensive one by mistake :D Banggood on the other hand is crap. The same Aliexpress products for more money and crap service. They cancelled my first payment and refused to give me the new member discount when I ran it again. Let me wait for 3 months to get part of my order and my multimeter had obviously been tossed around and was dirty. There were multiple items in the box and that was the only one covered in dirt and broken. Whoever packaged my order saw that it was dirty and put it in the box anyway and that is just unacceptable. Also the Microscope I ordered was listed as 3mp for $27 but was really a 1.2mp microscope that sells for $12.

Let's check what is "the little extra cost" :-D. I live in Canada, so I'm using CAD. Aliexpress: 100 of SI2301CDS cost 1.85 CAD + 1.39 CAD shipping. Digikey: 21.36 CAD + shipping. I didn't even bother to check shipping cost. So "the little extra cost" is >18.22 CAD. Maybe this is "little extra cost" for you. But for me electronics is a hobby and paying extra 600% (shipping not included) is way too much. The same story with Mouser.

If just one of the 0k1 transistors suffers from borderline behavior and forces you to spend two hours debugging on your hobby wage of as low as CAD $ 9 you already made up for that "reasonable extra". And don't forget the extra time disputing the seller. Additionally the professional suppliers handle their parts correctly. ESD-damaged parts mostly work but have a much lower life expectancy. When it comes to power transistors I'd consider the risk of fire too. DigiKey is expensive but not the only supplier. Here in Europe we have other distributors which are more economical at lower quantities. But yes, if all the factors add up "in phase" it can be worth the risk of course. Simultaneously I try not to forget that someone works for me a a wage which I don't like to work at. The prices that we pay in the western world better match the costs that we cause with our acquisitions - socially and ecologically: shipping just 100 transistors via airmail from the other end of the world isn't probably the most ecological mode of shopping. And counterfeiting isn't something that goes along with my ethical standards as well. But that's my personal opinion. We see: buying transistors isn't that easy :)

@@skeptical_bystander Exactly. If you buy quantity the prices do come down to the same levels though. Just small quantities make no sense. I have been trying to organize a giant group buy. If I could find 100 people to buy a full set of all resistors we could have 100 of each value for $5-6. The other option would be to make loot boxes. Each month you get a bunch of passives and a few transistors and connectors, some ICs, some consumables and 1 bigger item like a stepper or an ESP32 dev board. That would only make sense though with at least 1k orders a month guaranteed.

Production surplus sounds like a good deal because it should be original parts.

You are right. For bigger transistors I thought my crappy connectors and cables were enough. For smaller ones it would have been a good idea.

That is why I set the current first and raise the voltage after connecting the part. I did lose some LEDs until I noticed what is going on.

@@heyarno That is good enough for static parts like LEDs, where the voltage-current curve is constant and you only need to watch out when connecting the device. However for a FET it is different: you can connect it and then increase the voltage, however when you switch it on it will still draw much more current than the value set in the supply. (of course you can try to turn it on slowly so the peak will be less than when you suddenly switch it on)

@@heyarno this is always a good idea as well, because many of those cheaper power supplies with output filtering do tend to overshoot initially. So your solution is again a good idea for this test method.

@@Ormaaj Of course the preferable device for such measurements is an SMU (Source measuring unit). That is a power supply that is specified for usage as a voltage or current source in 4 quadrants, and also measurement of the resulting values. For "testing with what you happen to have available" a bench power supply and one or two DMMs is OK, but don't trust the capability of a bench powersupply as a current source... use a resistor to help it with that.

Glad you like my style. I think we should always concentrate on what matters;-)

You are welcome!

Thank you for sharing your experience. Some other commenters were cheated. Mainly with rare or expensive parts (at a cheap price)...

You are welcome!

:-) Thank you!

I still think the chance is smaller if you buy from a source with supplier check.

Btw, I forgot to mention, I usually buy on BangGood, and unfortunately, I did receive fake parts/equipment that is even dangerous like LiIon batteries, BMS'ses/loadbalancers etc... If something is really to good to be true, it usually isn't !

The new PS is on my bench and I like that I can key-in the desired voltage... I test most of the stuff I get. Especially batteries. And I file a dispute if they cheat.

That is always a safe way. Sometimes it does not work if you need the last percentages of a part...

@@AndreasSpiess Indeed. Plus if the parts get damaged, we need to wait another 2 weeks for new ones from China

Thank you!

I made a video about the testers, but I like this one most

dave from eevblog reviewed it, these products are based on an open-source design where all the logic is located on a microcontroller, the only differences between these products are just some additional features.

take a look at the original project: ogy.de/l46k

As engineers, we believe what we saw with our own eyes...

I assume you used the proper method to compare the two. It is not easy to measure those small resistances.

Andreas Spiess at the milliohm range I suppose reading resistance with the four wire method is impossible due to active circuit. What would the correct method be? Maybe a low ohm shunt in series to measure the mV drop across it to calculate current, and we can measure the mV of Vdg. Impossible to have a precise current reading and it's not easy to find a high precision shunt, so I suppose a comparison between official and Suspicious parts could be the solution.

The shunt will not help you too much because you always need the voltage across the transistor if you want it’s resistance The comparison is always best.

Andreas Spiess but for a MOSFET the voltage can be measured, if we have the current reading through the shunt we know it's the same current through the MOSFET Drain to Source. So we have the I and V across to calculate Ron.

@@AndreasSpiess i was sceptic from the beginning and compared the device against one bought from digikey . i used a calibrated transistor tester. when i showed the evidence the seller he immeadetly returned the money.

Thank you!

The principle behind it is quite simple. So it is probably cheaper to use equipment you already own.

Thank you!

It seems to be simple: Connect all three pins and press start... discovered it later with a destroyed transistor...

Maybe you watch the video about these transistors? There you find the links.

GM328A. I have watched again that bit as have also failed to spot a link in the description.

I also like to know that transistor testers link. May be the link is also not there because of the re-upload?

This is a link to the one I used: s.click.aliexpress.com/e/_srkjb3

^^^^ All very true. Exactly as I have discovered. You can get good products at great prices, but you have to do your homework and be a smart consumer. The Chinese aren't known for their honesty unfortunately.

Thank you for sharing your experience. I do not buy enough transistors to get a clear picture of who sells good quality and who not.

Thky hoy guys

Such a resistor would have helped, you are right. I cannot follwy your argument concerning 4:03

@@AndreasSpiess I'm not an expert, but you can extrapolate the other characteristics from the rise-time for those particular conditions, then change those times by altering the resistance and capacitance elements of the circuit to prevent ringing in your particular application. Changing local in-circuit values may shift the switching speed into an operational area where there is not a problem. (probably not a very good explanation, but I'm sure you get my drift)

Glad you enjoyed the video!

Of course. But I did not plan to destroy the transistors ;-)

Andreas Spiess Haha, obviously not. My remark was aimed at those who haven’t yet tried it. 😉

Good to know. So far, I never had such parts where they removed functions!

@@AndreasSpiess You can drive the digits, but can't blank the zero's with all four inputs high.

I would also assume it is more profitable to fake an expensive opamp than a cheap transistor. On the other hand I had never a faked MCU, which is also quite complex. But maybe easier to test.

I am no more active on HF.

You are welcome!

When i order from Conrad or Reichelt i get a headache from their search engine :D You search for a specific thing and get thouseands of completely different parts as a result. TME is also a decent option for people that live in Europe or near Poland. Most parts i order from AliExpress or LCSC, if it's a more expensive thing or i need it quick i look at TME and the last option is Mouser where i always have a shopping cart that slowly fills up until i hit the limit of free shipping.

@@Leif_YT I think reichelt is kind of dodgy too in some aspects. For some parts, you will get a part with that number, from some semiconductor manufacturer, somewhere. Not necessarily ON or TI like you would expect. Conrad is better in that regard, but usually a bit pricy. And they messed up shipping on my last order, so I couldn't finish my project this weekend. I am not mad, just disappointed. ;) The best search engine in my opinion has Digikey, followed by Mouser.

Not a "sensitive issue" merely facts. You get what you pay for.

Thank you for your explanations. I was not careful enough, I think.

Minimal order size is sometimes also a problem with distributors

Thank you!

Hallöchen alter Freund , wie geht es der Gemeinde?

Low-tech, high-Touch ;-)

You are welcome! For the moment I am only 914 miles away from Lincoln...

@@AndreasSpiess And you are funny! I do go to Czech Republic/Germany time to time to see my family and friends, but I don't know when my next trip happens, but I should see you in my next trip! Have a great day!

Bad luck. That is why I propose to do a quick test on arrival... Also because we would help AliWxpress to sort out the "cheaters"

You are right. I was too lazy :-(

@@AndreasSpiess I am lazy all the time - the difference is that I do not show my lazyness on youtube, because I am too lazy 😎

Good point. Thank you.

arcadeuk - Bam! Exactly! ‘TO-3’ package transistors, are the easiest to ‘de-cap’. If you compare a genuine 2N3055, with a Chinese 2N3055, you will see a HUGE difference in die size. A genuine 2N3055 is rated at 15 amperes. Chinese fakes fail at about 5 amperes. That’s not even half of the rated current! 2N3055’s have been used as pass transistors, in MANY power supply designs. They are often run very close to the operating parameters. If you ever have one fail, and have a collector to emitter short, you better hope that your power supply has over-voltage/over-current protection. Otherwise, whatever it’s powering, will become toast.

I would probably not buy products I depend on from unknown suppliers.

When repairing stuff, the question is always, why did it fail in the first place? So you can never be sure if your replacement parts are to blame or not.

If you read the other comments you can get fakes if you buy special or more expensive transistors

That seems to be a perfect application of such a wonderful device!

Shit happens. Like with my potentiometer. It also dies when the MOSFET died :-(

@Tiago Ferreira Sounds legit to me , mine are about 4 years old from RS Components.

@Tiago Ferreira I bought some Hooyi MOSFET (HYzzz), waiting for their arrival, hope what i get matches the datasheet. I also looked at some NCEzzz part from Wuxi, they have some nice ones. How have your NCE hold up? Personally i think that is the "trick" to by on Aliexpress. Yes, some parts are plain fake (duds, esp. for long EOL parts, or a parts uplabeled, say 4A diode becomes 15A, normal OPAmp becomes high precision low noise), but thats IMHO a case of "you get what you pay for". A 35A Thyristor for under 10¢, sure... That doesn't even cover the cost for the silicon needed for 35A but sure... Where there is a margin for counterfeiting, there will be counterfeiting. But other parts are just second source/compatible. That used to be normal in the semi-industry, how many companies made a 555. Or the basic National OP-Amps LM339/LM358/LM393. And the list goes on and on with such "standard components". That has always been an entry point for small non-brand shops. First in Korea, then Taiwan. And now China. For Germans reading this: you guys clearly didn't order from Reichelt in the 80s and 90s ;-) Back then you would get mostly second source chips from them. And often a different every time. Remains of that can still be found sometimes in their order-numbers from when they slowly cleaned up their act. You can now order a "MJ 15016 ONS" (ON Semi/Motorola) or a "MJ 15016 ISC" (Inchange Semi). Back then you could just order a "MJ 15016", surprise what you would get (but never brands like TI/Mot/Philips/etc.) One can shout his anger in the wind getting a "fake" LM2575 (or other from the same family) or IRF. Or one can embrace it and buy the "copy"/similar from XLSemi, Wuxi or other never heard of companies in the first place. "Fit for purpose" At the moment i try to find these hidden gems of Chinese second source with the help of the JLCPCB parts list.

I do not know if they are fake. But an Arduino should be stable. I never had problems so far. Pricing in the western world is mostly handling. The parts are very cheap if bought in thousands.

Thank you for sharing your experience!

I believe the less common a part is, the more likely it is to be genuine. It's just not worth faking if few people will buy it anyway.

Thank you!

I agree, there are a lot of fakes around. Usually expensive or rare products are more prone to be faked. The standard Chinese cheap stuff is already cheap enough, so faking is not very profitable, I think.

You are welcome!

There is a link in the description.

yep, defective parts seem to be very common when buying on aliexpress. It's always extra work to check everything you get from them. For me it's still usually worth it though.

As mentioned in the video: I would not use these parts for production runs. As you mention: Too much work and risk.

So this is the proof for my strategy: Test one when they arrive!

@@AndreasSpiess Indeed! As always you provide the perfectly methodical and logical process. We are so lucky to be able to benefit from your knowledge and experience! Amazing isn't it though that the humble transistor tester should be such a powerful investment amongst the expensive tools in our labs? Given that often the same sellers on AliExpress/eBay sell us the testers as sell us the components one might think they know we should be able to determine the fakes? But there must be some profit in it for them somewhere. I wonder though how many are "fake" and how many have simply been mislabelled in production because someone forgot to change the text to be engraved. We know already that a lot of the cheaper supplies are either seconds or production overrun.

I would not be brave enough to use Aliexpress parts for a manufacturing run. Because of the warranty cost and the risk for a bad customer satisfaction...

What would be interesting about a multimeter?

@@AndreasSpiess how to use it with the memory, and doing volt, amp, testing.

Unfortunately, this channel is more focussed on special topics. Maybe other channels cover those things. Maybe not with the same multimeter. But most are transferrable to other multimeters.

@@AndreasSpiess OK well that's your loss seems your not very flexible with your channel, unsubscribe, why even have a video 'How to improve your Maker Lab' if you don't know how to show how to use your tools.

You are right. It is a global problem. But in some places probably a little bigger than in others ;-)

:-)

The JFETs seem to be a problem. Many viewers reported the same experience.

You are right. And some even died because of that because I did not pay attention...

You can test it by applying the needed voltages and measure the currents according the data sheet (as I did). Or, maybe easier, you insert it into the place it belongs in your equipment and check it out.

Your comment point in the same direction as many others: The more expensive and the rarer a part, the higher the chance for a fake.

You are welcome!

Ah I wrote the same thing before finding your comment! That is so true!

The 6020 is very easily mixed with the 6020p. Happened to me, too

ahh ok, I did not realise there were N channel versions of this. However, looking back at my orders and on the the actual MOSFETS, they are clearly marked having a P. Could have been a some dud batches with incorrect labeling.

You are right. I think I mentioned it in the video.

As I mentioned: Your current power supply is good for testing.

@@AndreasSpiess Thank you. First batch will be International Rectifier IRF540N , purchased on local store.... I'll update the Drive folder as i go: drive.google.com/drive/folders/1H5iCqIbPty6IsIaEM8H9dOra2z6zHRn_?usp=sharing For now Transistor testers had almost same results for two mosfets of the same batch / purchase. For the current setup the RDS values will be writen in a spreadsheet

The first one gave around 0.036 Ohm, which is not far from the datasheet ( 0,044 with Vds=100V). By the way the HEXFET did not get hot at all and the turn on effect as mentioned in the video did occur at 4V. Fits for purpose and complies with test setup

I do not accept bad quality and open a documented dispute. I always got my money back.

Sad to hear your Granfather died. Here you see our different ages: My father was 92 when he recenty died. So I am much more used to funearals. You are probably more invited to weddings, I am invited to funerals. That is how life proceeds. Just to warn you: The transistor tester does not work wit hFETS, only with BJTs. Maybe I will once build my own using an Arduino and make a video about it.

yes you are more experienced about life. it was a big shock to me. i used to discuss lots of things with him. but one of his specialties was his knowledge of the self, meditation, prayer and religious knowledge. so this discussion i see here ukposts.info/have/v-deo/qYmYnGt6lqmZ1X0.html was what he used to talk whenever he was around.

I made a video about them. There you find the links.

TNX.

A good decision. I was not so unlucky so far.

I am never sure if it would be good for these people if I would stop to buy their work. Would they get better-paid work instead?

@@AndreasSpiess U wouldn't make the world a better place not buying stuff from China. But our industries+governments can make a change in China or India or Africa. And we are the ones that have at least some influence on what they do. It is an interesting fact that after 2000 when China opened a lil bit more to capitalism the amount of people that tried to escape to Japan decreased dramatically (in a good sense). For people interested I am not a good person to speak to but can forward you to lovely maker queen Naomi Wu. Please find her channel and let her know again that my gene-stealer agents are still out there and will get that little peace of DNA I need... OOOOPS got a lil bit off-topic now. Just me. And always listen to her talking mandarin... will give you a much broader + complete view of her than just her english version. It doesn't matter if you understand mandarin or not... so much information about her is transmitted in the way she is speaking her mother tongue. She is a true rebel and a punk and HOT beyond believe + always properly dressed.

Some other commenters also mentioned JFETS as being faked. It seems we have to pay attention to this category of parts

Thank you!

You are very brave to go so close to the limits ;-)

You are welcome!

Some commenters mentioned that it is not a good idea to buy rare transistors on Aliexpress because often, they are faked. Your way is much better. Especially giving feedback helps others!

You are right. I was too lazy...

Thank you!

Can the data sheet be trusted ;-)

I am glad if my packages will arrive before the 28 days. Currently most of China is blocked and I assume it will take quite a sile till everything is working again... So I do not fear anything. Packages at your retailer might be as dangerous because their supply chain is fater than ours.

Testing is always good. And sometimes even needed as your example shows. Other comments suggest that the more special and expensive a part is the bigger the chance for a fake.

Thank you!

This would have been another possibility.

Most of the power FETs are anyway too strong for my purposes and they never get even warm... So you are right.

You are welcome!

I think this is a good strategy. A good sleep is very important ;-)

This is quite stragne. Usually the cheap Chinese parts are not faked. If you want to have a reliable Chinese supplier you have to go with LCSC.

@@AndreasSpiess Yes that was a bit disappointing. I am still inexperienced and it took me a long time to find out that the part was not right. Ordered some more from different sellers on Aliexpress. am curious if I was just unlucky or if several sellers are not reliable. I had indeed seen LCSC. Would have liked to order there but the shipping costs are very high.

You are welcome!

Concerning speed: I have viewers who watch my videos in 2x speed because I am too slow for them ;-) I love UKposts for its replay function and I use it also for the good videos with lots of information.

@@AndreasSpiess Would it cause you pain to slow it down even a wee bit ? 19200 Baud maybe ? LOL

At least LCSC is (as far as I know) a supplier, so you can count on some constant quality and service. AliExpress is only a middleman between you and many, many Shenzen market stalls. It will depend on the actual store where you order what will be the quality. AliExpress only facilitates getting your money back when the quality is bad, but it does not reimburse you the time lost on dealing with it :-)

I myself started to use LCSC as opposed to AliExpress but from time to time I/m still having to fall back to AliExpress simply because more often than not LCSC doesn't have a broad range of parts that I need, and there are only 2 options left. 1. go back to Ali, or 2. Pay an inflated price for parts (that should really cost a lot less) from a reputable local seller that also charges you over the odds for the postage as well.

@@ovi_4 1. AliExpress sellers can't be trusted with handling esd or moisture sensitive ICs, let alone their storage and packaging. Proper packaging and storage costs money. 2. Overly-priced is relative. 3. LCSC also isn't really exemplary at packaging moisture sensitive parts, so I like to buy those from other distributors.

I once tried to replace all parts in my current project with parts available on LCSC and ist wasn't possible. They didn't even have half of the needed components even after I replaced as much as possible.

Maybe, if you order in bulk and once a year. Otherwise, their shipping cost is what makes the total price less viable than a EU source for me.

I hope you got your money back.

@@AndreasSpiess Nope, this was not Aliexpress, just a random webpage.

I even cannot read the colors anymore. The colors are often very bad to distinguish (for me). So I always measure the resistors before I use them.

You are right. Here, the problem with distributors are added cost for small orders and shipping cost. Usually prohibitive for makers.

Supercaps are sometime like those 8000mAh 18650 😂

@@AndreasSpiess Shipping cost are free when above ~30€, and so much faster! Something to think about. Yet, I'm still mainly buying in China.

@@wildinthejardin I finally bought a nice 2.5F supercap in a well known distributor. Impressive ... and still made in China ;)

I had exactly the same problem with supercaps. Perhaps it was the same dealer? Mine were these: www.aliexpress.com/item/32631591419.html?spm=a2g0s.issue_5ptha.0.0.278c4c4d5sRJOY

I think I did two videos about Zigbee.

I never used those because their additional functions were not needed for my projects so far.

I agree with Repairman

I always use the dispute process. I assume that they treat bad quality differently than lost packages. If I get bad products or damaged products it is important for me to give feedback. Also for the next buyer.

I have ordered a lot of products on Aliexpress and dispute process is far from perfect. For example I had the Aliexpress judge determine that I could only get a refund if I send back the defective item to china. And the postage would have cost more than the item was worth. Also if you want to contact Aliexpress there is no number that you can call. There isn't even an email address on the whole website from Aliexpress. So if you make your dispute too late then there's no way for you to talk to anybody. Moreover lately they changed the system so the order closes automatically after a certain time. Before you could "extend the time for the seller" and give the seller more time to still deliver the package without losing your ability to dispute. All in all I dread the system.

Ebay is 100 times better buyer protection wise and if everything else fails you can still talk to a human in ebay support. Aliexpress is not even close from a buyer safety persepective. I only use Aliexpress because I can't get some parts on Ebay and because of the price.

@@kwinzman I agree that ebay is much better, the problem is they often dont sell what I need, or are much more expensive. With aliexpress you always have to watch out for expiring buyer protection, check every order etc. I always contact the seller if a package has not arrived yet and tell the seller to extend the purchase protection (they can do that), or if it ends in just a few days, I additionally open a dispute and tell them I will close it if they extend the purchase protection. Aliexpress does have a live chat, but they have not been very helpful for me. So far the Aliexpress judges have been on my side when there was a problem, but yes, the system is far from good.

All (yes, ALL) my disputes with AliExpress vendors were about shipping. At some point in 2018 or so one of their usual shipping providers, Yanwen, seems to have gone rogue and just delivered about 80% of the ordered packages. And then there were the clear cheaters that just didn't post anything and gave you a non-working tracking code, or the ones that started a delivery but the shipping company never got the package. All of those were deemed as refund situations by AliExpress, so I can not complain at all.