We all know the old saw: if it’s too good to be true, it probably is. But nowhere does this rule seem to break down as regularly as when we order parts. Banggood, AliExpress, and eBay are flooded with parts ready to be magically transported across the globe to our doorsteps, all at prices that seem to defy the laws of economics.
Most of these transactions go off without a hitch and we get exactly what we need to complete our Next Cool Thing. But it’s not always so smooth, as [Kerry Wong] recently discovered with an eBay order that resulted in some suspicious chips. [Kerry] ordered the AD633 analog multiplier chips as a follow-up to his recent Lorenz Attractor X-Y recorder project, where he used an Arduino to generate the chaotic butterfly’s data set as a demo for the vintage instrument. Challenged in the comments to do it again in analog, [Kerry] did his homework and found a circuit to make it happen. The needed multipliers were $10 a pop on DigiKey, so he sourced cheaper chips from eBay. The $2 chips seemed legit, with the Analog Devices logo and everything, but the circuit didn’t work. [Kerry]’s diagnosis in the video below is interesting, and it’s clear that the chips are fakes. Caveat emptor.
Here’s hoping that [Kerry] sources good chips soon and regales us with a successful build. Until then, what are your experiences with cheap chips? Have you been burned by overseas or domestic suppliers before? Does any single supplier seem like a better bet to you, or is it all hit or miss? Sound off in the comments below.
I’ve had a lot of fake LM317 regulators that didn’t behave correctly and then went dead short at 24V. Serials were all CCOXC with fairly legit looking ST marks but they are dangerous counterfeits
Forgive my ignorance… CCOXC?
That’s part of the marking on ST LM317 packages.
E.G. https://protostack.com.au/wp-content/uploads/SC-VR-317T.jpg
There are several reasons why you will get duds.
1. The chip is an outright fake something completely different to what you wanted.
2. The chip is a lower spec part that has been relabelled, some people won’t notice but if you use a part with to the limits of its expected spec and it is a lesser part not as capable it will fail.
3. The chip is recovered from e-waste and is faulty either through original device failure or by the recovery process.
4. The chip is a reject from the manufacturer that has been sold instead of destroyed.
Wonder if one sees more “fakes” where the originals are high-priced? In other words the more the originals cost, the more fakes there are.
Why would “overproduced” be linked to “counterfeit”?
Could you clarify? Why? Isn’t it possible to mess up an order and make too many of an otherwise good product, thus needing to sell the surplus?
Grey Shift products perhaps?
Because they still aren’t legitimate parts (although physically they are the same). Production is only a portion of the cost of a part, if I send a design out to be built, and they make extras above what I ordered and distribute those, then it would be a counterfeit as they weren’t licensed to make it distribute those extra parts which are now competing against the legitimate ones.
They aren’t legitimate only if the customer has exclusive rights to the device. Billions of semiconductors are produced each year the intellectual property for which belongs to the manufacturer, who can rightfully make as many as he pleases.
This is very common in consumer goods manufacturing. The factory (or in this case semiconductor foundry) which has been contracted to produce certain number of items will over produce without telling the customer. They are then sold in they gray market but they often don’t have quality control or testing.
Not entirely true, at least not in the apparel industry. We , as general principle, always receive more goods than ordered. It’s a way of ensuring that shipping damages and/or poor QC, wont result in unfulfilled orders. AT least to an extent, I mean if a truck burns in transit you will not recoup that. But a stowaway rodent, chewing through boxes can be recovered.
and to distinguish it from the above, is the that overproduced goods are delivers the owner and sent to some shady backroom dealer.But the short answer is, yes, they are considered ‘counterfeit’
Overproduction always happens in semiconductor manufacturing. Yields are always unknown in advance, and enough devices must be made to guarantee there will be enough devices to meet the contract. For instance, for an order of 10,000 pieces, the manufacturer might process 20 wafers of 650 parts each, not knowing if the actual yield would be 80% or 95%. Devices are probe-tested on the wafer with a yield of 88% (11,440 good devices). The manufacturer cuts up 18 wafers, leaving 2 wafers in reserve. The 10,296 good devices are packaged and tested more thoroughly; an additional 1% have failed in cutting and packaging. There are now 10,193 good devices, of which 10,000 are sent to the contract customer (who, by the way, may do additional testing and reject some) and the manufacturer retains 193 good devices as stock and still has 2 wafers to potentially cut, package and sell another 1,144 ICs.
Reminds me of this old chestnut…
“”A number of years ago, IBM Canada ordered some parts from a new supplier in Japan. The company noted in its order that acceptable quality allowed for 1.5 per cent defects (a fairly high standard in North America at the time).
The Japanese sent the order, with a few parts packaged separately in plastic. The accompanying letter said: “We don’t know why you want 1.5 per cent defective parts, but for your convenience, we’ve packed them separately.” “”
“Very low serial numbers, like very low MAC ID addresses, are a hallmark of the “ghost shift”, i.e. the shift that happens very late at night when a rouge worker enters the factory and runs the production machine off the books. Significantly, ghost shifts are often run using marginal material that would normally be disposed of but were intercepted on the way to the grinder. As a result, the markings and characteristics of the material often look absolutely authentic, because the ghost material is a product of the same line as genuine material.”
-from https://www.bunniestudios.com/blog/?p=918
Had the same happen to me buying “Ad597 K-Type Thermocouple Temperature Control Board Module Ultimaker New” for £4 on ebay. Should have known it was a bit shady because off the shelf a single AD597 costs about £8. But.. worth the try.
The temperature values were no where near that of an original. I have to admit though, I used the IC out of spec, supplying less voltage, which works fine for the real deal.
Of course, when I challenged the seller on ebay (chinese webshop, with an english drop address), they first denied the devices were fake, and after telling them several reasons why they were indeed fake, they just did’t respond anymore, nor did they refund anything.
But on the other hand – I did use the PCB they were on, I just soldered on a new AD597.
I think that some of these “chines replys” on ebay are fake attempts to solve a problem. From my last three sellers with problem cases (all different) two handled problems all the same way. “We need a photo of the part”, done. “Of the envelope, too”, done. “Did you google it?” Yes, /me not so stupid. “Do you accept less money because else my boss will be angry?” No, my wife will beat me if I pay for broken stuff, no way. Then silence, I open a refund case, still silence, paypal refunds. Some sales drone making its spiel.
Typically was that these sellers sold everything. Nail polish, soap, screws, wipers, modules, nissan nuddles, bed sheets, ICs, adult toyes, just everything.
On the other hand there are some chinese electronics-only sellers that handle problems very fast and very fair, almost to there disadvantage. I complain, I get my money back and can keep the parts.
YES!
Had that happen, as well as sending the parts by slow boat in the first place. eBay should extend their ‘claim time limit’, or at the very least, allow a purchaser to register a “possible claim” that extends the time limit by a respectable amount.
I’ve had issues with Chinese vendors on electronics. Its rather rare considering how many purchases I make on a yearly basis. Sometimes its QC problems, sometimes its fewer parts than ordered. Usually, they just don’t ship the items hoping you’ll forget until after eBay’s refund policy expires. After 4 weeks I contact them to complain. Its always the same response “could you please wait a little longer?” or “will you accept a partial refund?”. By then, I’ve lost 4 weeks and ordering from another vendor will add another 3 to 5 weeks to the wait. Sometimes the parts DO show up 6 weeks later, sometimes never and I have to re-order from another vendor, which I detest the loss of time from the initial shady vendor but its part of the experience. In ALL cases, if I suspect foul play, I always let the seller know that I will get eBay involved and issue a negative feedback. That usually gets the response of cancelling the order and a full refund. Cancelling your order prevents you from issuing negative feedback against them because eBay penalizes them. Sometimes the parts show up, sometimes not. Its always a gamble with eBay vendors. I’ve not had an issue with BANGGOOD but then again, I’ve not ordered much fro them.
Peace and blessings/
seller doesnt have to refund, complain to paypal, they will
but those chips should be ok, plenty of people use them, they are clones and do work
It would have been nice to see baseline testing of a genuine device to verify that the test was set up correctly, but that would have required having one! I can understand how people can make money from out of spec devices but it seems a lot of effort to create fake packaging with some unknown chip inside for probably little return. Maybe they are complete test failures that someone picked up thinking they were just out of spec. That would make more commercial sense although it doesn’t help the buyer.
That isn’t what “fake” means, though. Unauthorized parts made by the real factory are real parts.
I had the same problem with AD633 purchased on Ebay. I put a digikey part (AD633) in the socket and it work without any issue. I also saw the high current with these parts. The seller says he will issue a refund.
I once asked a gentleman giving a seminar on counterfeit components and an SMTA event just how far down the component food chain to expect to see counterfeit parts. I mean, really, there had to be a limit where the part just wasn’t worth the effort. Expensive large-scale IC’s, definitely worth the effort to counterfeit. Generic 2N2222A transistors ? The answer shocked me – he identified that components were being “recycled” all the way down to chip caps and resistors. There are no parts too low on the food chain not to counterfeit.
And the people removing the parts from scrap boards, washing them in the river and leaving them on the sidewalk to dry felt that they were providing a great service by recycling all of those components.
Be careful where you source your parts!
After seeing the Fake Cap it made me wonder why go through all the effort to make the Counterfeit… Check out this image of a counterfeit Cap that someone went through a lot trouble to create…. yikes…
https://www.eevblog.com/forum/projects/warning-fake-large-electrolytic-on-ebay-!!/
Errm… that link just seems to send me to the front page of their forum…
Click the link and then add the !!/ to the url in the browser.
RFC’s are for lamers!!
The pic –
http://www.discovercircuits.com/dc-mag/Issue_4/Photos/FakeCapacitor1.jpg
Tried that, it did the same thing.
https://www.eevblog.com/forum/projects/warning-fake-large-electrolytic-on-ebay-%21%21/
well surprise surprise … your browser is RFC complaint to.
Heh, yeah, using funny characters in URLs is never guaranteed to work.
As to the picture… I can just imagine someone opening up that Rubycon capacitor, finding another smaller electrolytic… eventually opening up the final one to reveal an 0201 SMD ceramic.
@[Redhatter (VK4MSL)]
ROFLMAO
50Volt 6800uF capacitor made by Babushka. Includes free 100pF ceramic.
High-value electrolytic capacitors are *expensive* and they have significant brand premiums. They’re an obvious thing to counterfeit.
I came across some WIMA capacitors that where merely a bunch of cheap MLCC capacitors glued together, and placed in a trademark red case. The color of the red case is usually off a little. Like I always say, buy from a reputable dealer, or even direct if you can! I do a lot of audio work, so the final result of these fake parts are stunningly obvious, but even in other applications, a fake Mica or glass capacitor will give you lot’s of trouble! When ever I have the notion to repair a cheap Chinese product, one of the first things I do is look for shorted-out capacitors in voltage regulator sections, and that often solves the problem. Audio distortion? Replace the op-amps and resistors and capacitors! Another cheap Chinese trick is to buy a large lot of defective parts (like I.C.s that over-heat due to heat junction defects), they are real I.C.’s, but should have been recycled, not resold! Here is where all that overly expensive test equipment can save your ass! Like I said, I mostly work on audio, so I listen, and I heat-test-probe parts instead of getting the equipment that I really need. I mostly work with designing and building high-end audio electronics, so I can usually get away without the test equipment. Anyone want to donate some good test equipment? Some of my test gear is so old, it just says “Made by God” on the back, and I still need to build special test jigs, just to get the specs I need!
We can only hope that at some point in the future the amount of poverty level labor in China decreases to the point we don’t see as much of this:
Just one example of many
https://i.stack.imgur.com/dwxaH.jpg
What is even worse is that the incentives and culture to saving is so strong that everyone is banking it all away for their future of wealth and comfort. It is all going to get stolen, there is no doubt, there is no way that the system can or will stop a all of 1.2 billion and every foreigner form figuring out how to steal a billion lifetimes of slavish labor with dreams of a comfortable retirement will be for naught. If anything that savings sitting in banks and approved investments, their very existence incentives corruption, it is low hanging fruit.
For example in the US management in most corporations did it 100% legally by intentionally-on-accident crashing fully funded company pensions they were entrusted with managing after having taken out insurance contracts against loss of value with the insurance payout to benefit executive compensation only. Kind of evil but legal electron tunnelling the cash into their pockets with a substantial thermodynamic loss, but any $$$ form no $$$ is a saweet profit for the execs.
That filler might as well be gunpowder, probably a used e-cig cell. Ultrafire, go figure.
Oh! the irony of the brad name!
Old News
http://www.gao.gov/products/GAO-12-375
Pretty funny read until you realize that this is endemic.
Ooof that sucks big time. What a bummer, if not exactly surprising.
Their wIllingness to supply parts that do not exist has to applauded though.
I like that they supplied parts with non-existent part numbers.
I should jump in and order a flux capacitor; part number 1984
Once upon a time, a certain, now defunct, computer company with a large retail chain bought a lot of Z80’s from SGS that were manufactured in Italy. They were, of course, the cheapest vendor.
Mostly they worked fine. 90+% of the time. There were, however, two apps that crashed reliably. Every time. One was the word processor, the other was a pretty popular game. Much digging/debugging later, we discovered that the processors didn’t have the alternate register set. Most code never used it, but these two made extensive use of the alternate registers. Oops.
Replace it with Genuine Zilog and you’re off.
Thanks Captain Zilog!
This? http://www.vcfed.org/forum/showthread.php?57369-Substandard-Z80s
I’m amazed they worked most of the time. I suppose it depends on the architecture of whichever computer it was. Using the alternate set during interrupts is largely what they were designed for, or one set for an OS, the other for applications. If this computer didn’t do that, then I suppose you’d get away with it.
Also, if it was CP/M (a guess, but you said “word processor” and Z80), a lot of CP/M stuff is 8080-compatible, the 8080 didn’t have the alternate registers. So that could be something to do with it.
Still, amazed the supplier was able to get away with it. Surely a problem like that would be discovered quickly by many of their other customers?
It’s a bit amazing that a voltage multiplier still costs 10$ in this day and age, and that you have to resort to using something like a LM13700 transconductance amplifier to get a similar effect.
All of these analog amp/mixer/muxer components are becomming savagely expensive at low volume because of more modern design alternatives. Especially in DIP packages. I payed $20 for one instrumentation amplifier chip this year :(
https://upload.wikimedia.org/wikipedia/commons/thumb/0/04/Analog_multiplier_full.svg/800px-Analog_multiplier_full.svg.png
You just need some op-amps. You can get 4 op-amps per chip real cheap.
That’s a log-antilog multiplier, usable only for negative inputs. Also, diodes have poor log conformity; transistor junctions should be used.
A four quadrant multiplier has a much different circuit, and even devices with a fairly poor (1%) untrimmed accuracy are not cheap. All the critical semiconductors need to be thermally coupled (i.e. on one chip for best results) or thermal effects may produce problems. Good analog design isn’t easy.
I had a bad-luck experience too, on Aliexpress.
Bought 200 2981 chips, look very real. 90% of them work fine, 5% died quickly, 5% were DOA.
So 20 very unhappy customers and some egg on face.
My conclusion is, cheap China chips are fine for hobby projects, you’re fine most of the time.
For anything else, better pay up at Mouser.
Which customers ? Did you resell those low-cost and untested parts of dubious origin to yours ??
Yeah, unhappy customers can be such a “bad-luck” experience… ;)
Maybe they didn’t like waiting for real components to show up? Or maybe they did work good enough to pass the standard tests?
But go on being an asshole if it makes you feel better.
Use Aliexpress for heat-sinks, screws/nuts/washers (sometimes) spacers, headers, some connectors, things like that. Do not buy critical parts from there, ever! (sorry my dear Chinese friends). The Chinese do make some wonderful things at some great prices, but corruption is like a disease, and it has infected everywhere, and everything! Careful out there, it’s like the 70’s, where the Japanese could not be trusted, but now make some of the best things in the world! Hopefully the Chinese will find the value of integrity and will one day become a world leader in quality. Good luck to all the hard-working and Chinese of high integrity, that so hard try to make the world a better place. My hats off to you, and a beer on me. Don’t give up, keep trying your best!
*Looks at username* Obscure Beatles reference?
https://youtu.be/YxgEwZ1qw5I
You just should understand their business environment if you’re going to source your stuff from there. Instead of being so culturally judgmental.
There is an expectation that you buy the parts through the factory that is doing assembly. They don’t have a system where specifications are of part numbers; specifications are of how the finished product works! And the factory is expected to make modifications, that is how they do good work and help you get your costs down! Parts are generally sold through business to business relationships between factories.
In this environment, just trying to buy the plain parts by part number is dubious, because it isn’t how they do business. They would not even anticipate a person trying to do that! Instead they view a “part number” as a set of capabilities. You give a part number for a transistor, they look up the capabilities their book says it has, and that’s what they think you want. Selling a different one with the same part number doesn’t even look dishonest from their perspective.
Whereas trying to just buy the plain parts without going through the factory doing the assembly makes you look like a potentially dishonest fly-by-night business who is going out of their way and paying higher prices just to avoid building business relationships with suppliers! A strange thing indeed, from their perspective. Everything in China is based on relationships, a client business has a relationship with a factory that does the assembly, and that factory has relationships with other factories that make different components, and they’re all working together to find the cheapest parts that still result in a working product. So of course they don’t supply consistent parts when you’re bypassing that and not building any relationships at all, and they’ve never even seen what your product is!
That’s why I only import parts based on expected capability, with an understanding that there is no error margin, I have to add that myself. And when I need a specific part instead of a capability, I buy from a local distributor! It is way more about misunderstanding than “corruption.”
I had a bad experience buying IRF-510 mosfets. I blogged about it on my site and even got featured on HaD earlier this year:
http://miscdotgeek.com/genuine-irf510/
I recently needed to buy some RF mosfets and avoided ebay and aliexpress and went to a ham radio vendor. Once bitten, twice shy!
Check the supplier’s return policy before you buy. If they pay for return shipping, you have a much better chance of getting something that works. Otherwise, if your order cost’s less than return shipping, economics insure your going to get the stuff they know doesn’t work. That’s the magic formula.
On eBay if you get defective item and you can give reasonable proof then seller will refund you without item return. Had few occasions with batteries that don’t have stated capacity and USB and SD memories that were fakes, got money back every time without sending item back. Sometimes you have to provide picture of destroyed item but most sellers don’t ask for that.
Also look out for cheap stuff with high shipping. There’s some sellers sell crap they know is crap and game the system by padding the shipping for their profit, not caring if you have to pay to return it to the, because when they refund the minimal item cost they are still pocketing the extra $10 for nothing in the original shipping.
A friend got a lightbar that didn’t work from ebay. The seller told him to send a picture of it destroyed and they would send him a new one. He cut it in half, sent a picture, got the new one, and repaired the two halves into smaller lightbars.
Love it!
I sen’t pictures of a freight damaged laminator and got a refund, then fixed the laminator as it was going to be modded for PCB toner transfer anyway.
Most chinese retailers should be praised for such a generous commercial attitude, instead of this constant bashing.
Like anywhere, stuff purchased at a bargain price from unofficial source requires extra caution and comes without guarantee of operation or safety.
The laminator wasn’t from China and it wasn’t cheap. It was also very heavy and would have cost significantly to freight back and forth again.
its ILLEGAL to ship counterfeits in EU (and probably most of civilized world), Ebay knows this and will not require sending back fakes
How about fake LM35 TO92 temp sensors. A bit of sand paper, little acetone, alcohol to smooth the surface. Cheap off center laser etching. Wolla, you take a cheap 2n2222 transistor into a $2 LM35.
10 parts for under $5 on Ebay. All fakes.
I just received a NOS MC6847 video display processor. Appears legit, but it is sorta working but faulty. I made a youtube video showing the symptoms https://www.youtube.com/watch?v=vb0PiQy1bhA
to be fair its a 30 year old chip, not to mention most likely a pull, ask seller for another working one
That’s just an assembly language instruction …
0000 ORG 0100
0100 START: EB 00 HACF ; // Halt and Catch Fire
0102 JP START:
I have received many fakes from China/Ebay. Not for production of course.
I am not complaining as I am still ahead in savings. On Ebay you read “new” but you know that at best it’s a secondhand part that has been removed from a circuit board that has been washed in a creek or river.
Here’s what to look for mostly for chips –
The top surface is ground to remove the original laser etching so that it can be reprinted in lower quality.
The regrinding reduces the depth of the pin 1 marker or any other original detents.
When they clean the top after grinding there is often waste material left in the pin 1 marker or other detents.
The grinding also leaves an oily feel and a distinct smell but these things don’t help *before* you purchase.
Laser markings are generally hard to see. If you see a bright clear part number then it’s likely fake.
Original markings are a high color temperature of white. Fake markings are a much lower color temperature which I assume looks more yellow to those who can see color.
On DIP chips the pins are bent in when inserted into a PCB. The recyclers bend the pins back out but tend to bend them further out than an original.
QFPs will often have bent pins and no chip carrier for fakes.
You will see where solder has been removed on used chips / components.
So there are three types of purchases to me –
New parts – and the price reflects this
Secondhand parts – always cheaper than an original new and acceptable for some purposes
Re-labeled parts – useless, they’re relabeled because no one want to buy the genuine part number
Most of the Chinese sellers on ebay watermark their pics and you can see the fakes
Not any more, well very rarely as I am experienced at picking the fakes.
They most often do put up the actual pictures being an example of the product and you can see the fakes.
Speaking from experience or ignorance?
Send it to electronupdate (YT channel), or http://vintageteardown.com/ for decapping.
I would also test if those chinese AD633 dont act like an opamp :)
http://richfiles.solarbotics.net/eb/GreenLEDBad3.jpg
Bought these LED displays off ebay to replace a bunch of MAX7219 modules that shipped with red LED displays… That’s a whole other story in itself… I ordered one of the only listings I could find that said Green LED in the title and description… When they arrived as RED LEDs… They actually tried to claim “green is board color”… Really? -__- Yeah, ebay made the partial refund go through, especially since they changed the listing after I filed the dispute. I accepted a refund of just enough to buy replacement green LED displays (since the Max7219 modules seemed to work). The replacements I got… about 40% were bad out of the package, and as I ran them, they continued losing segments. I was so paranoid the driver boars were blowing them, but everything was within spec… The LED were just dying. In the end, over 50% of the modules had failures, and I refused to use any. Got a 100% refund from ebay. Ordered from Mouser instead, and I’ve not had trouble. Sure, it cost me four times what I spent on the cheap Chinese ebay garbage… But I didn’t get garbage, and would have been worth it to save the time and stress and testing.
I have ZERO FAITH in Chinese electronics off ebay. If that country wanted to be taken seriously, it’d crack down on that garbage. The Chinese government ought to be concerned with it’s nation’s image! Have some pride! Instead, China is practically and ADJECTIVE for GARBAGE electronics! Sad!
I know fully well that that +50% failure rate LED module is made in the same land that a brand new iPhone is made… You pay for quality, and it’s not so much that China makes nothing but trash, but rather, that China has the absurdly extreme capacity to build to a price with such a razor’s edge to the extremes, that their lowest quality products can range from “fall apart while unpacking it” to “Young Woman Killed By Charger” being plastered over the headlines. You can pay handsomely for a quality produced item, or pay pennies for utter refuse… And China can find a way to profit on the ENTIRE range…
The fact that you can even profit on that entire spectrum of quality is why China is so good at counterfeiting… Even the cheapest parts can turn a profit if you can counterfeit them! This is the nation famous for sewer scum being rendered into cooking oil, and fake eggs and rice. When GOVERNMENTS have to issue warnings about the counterfeit electronic garbage coming from your nation… You should not be proud… It’s shameful!
I can only hope that China someday gets tired of being made the butt of every cheap X joke, and puts in an effort to repair their image.
Remember when “Made in Japan” use to be a joke?
“What do you mean, Ost? All the best stuff is made in Japan!” XD
Japan really went in a different direction than China. Both started out as cheap overseas labor, but there’s this work ethic in Japan that just really pushed Japan into a positive direction. I mean, yeah, they’ve had their recessions and such, but modern Japan is a transformed nation, and I will still buy something made in Japan over Made in China. I’ve always wanted to snag an old Commodore typewriter for my collection of vintage stuff… I have a LOT of vintage calculators and computers. Back int he 1960s, calculators were made of discrete components, and were built to be serviceable. In the late 1960s and early 70s, cheap Japanese products began to flood the market. Commodore had a role in the early calculator markets, and because of their prior experience being pushed out of the typewriter market by cheap asian products, were ahead of the game. They made deals with Japanese manufacturers to brand easter hardware with the Commodore brand name. They managed to stay int he game for several years, till they jumped boat to the computer market. Again, they saw that the calculator was well on it’s way to shifting from a significantly profitable technology to a commodity item.
With Japan’s work ethic, they took to manufacturing with resolve. China has simply driven the bottom line lower and lower to meet the insane western demand for cheaper and cheaper products. It’s fine to want cheap, but you have to set a lower bar. Below a certain point, and you sacrifice quality. China, like James Cameron, is perfectly fine trying to discover how low the bar can go.
“… positive work ethic …”
Yeah, dying suddenly from overwork is definitely worth economic health and product quality.
(Yes, I know that this also applies in China. That just means that there’s a deeper, systemic cause for these issues.)
You can safely bet that ALL Chinese/ebay/alibaba components are counterfeit with varying levels of exactness, but often with smaller die-size to cut costs. Chinese parts rarely match the specs in the datasheet. Sometimes that’s a problem, other times not. YMMV.
https://www.youtube.com/watch?v=R2J5xrSiNrI
I bought some LM675 power Op-Amps off ebay a while back…
If you look a post or two up, you’ll see the LEDs I bought at the same time…
Needless to say, I never even bothered using them, and switched instead to an American surplus supplier who had some NOS power audio drivers that were made in Japan back in the 90s
If you are not used to working with analog parts, at least some of your issues may be because of your circuit layout. Lead length, dress, and routing are important, as is having a proper low noise power supply and proper bypassing. Layout techniques that work with microcontrollers will not necessarily work well with opamps.
It would have been interesting if he put a scope on the output to see if it was DC or if it was was oscillating.
I bought some modules with fake FT232 from an EBay seller. I use a Macbook, so I never found out, until I checked the serial numbers of all of the chips, and they were all the same. :)
Also purchased some cheap attiny2313’s which looked odd. And the fuses had been programmed for an internal 4MHz clock instead of the default internal 8MHz clock. And when I compared them to other attiny2313’s I had, it was clear that they had been relabelled. Never could find any fault with them, but I guess they were pulls and relabelled. Link for pictures: https://www.facebook.com/photo.php?fbid=10200366004910217&l=904357b65c
I bought some really cheap MCP6001 op-amps in SOT-23 on Aliexpress… They arrived in cut-tape looking good…
I left them in a drawer for a few months and then tried them in a design, which failed. Next, I tried them in a simple unity gain buffer configuration: output was about half of input :-(
I’ve learned to stick to Aliexpress sellers that have proved to sell good parts. I think Aliexpress is good for resistor/cap reels, small transistors, and mechanical parts, but I wouldn’t’ buy any IC that is project-critical from there.
Perhaps, we should create a “tripadvisor” for Aliexpress sellers of electronic parts for the community here :-)
Chinese business expects you to be building relationships with suppliers, so return business to the people who were selling what you wanted is exactly what they expect.
They also expect you to know that the cheapest parts are really cheap, and have a use case for it. Their parts are generally honestly priced, so if you think you’re finding deals, you’re scamming yourself. :)
You can’t build a tripadvisor-like site easily, because in the Chinese system you’re supposed to get positive recommendations from your existing business network, and never say anything bad about anybody. Their system just doesn’t make room for western-style reviews. You’re supposed to be making friends you trust, and trying out suppliers who your friends say good things about. You’d want it to be more like twitter or facebook, where your social connections could give a positive recommendation, but it isn’t allowed to say anything bad. Then you could get buy-in from the China.
I have been through this rodeo twice with Aliexpress. My first was with some plasma scan ICs. All 50 of them had pins that were corroded, bent, or missing. Of course, they wouldn’t give me a refund unless I showed them not working and could prove that I was a “licensed installer.” I ended up filing a dispute with my credit card company. They ended up refunding half of my money and got a 1 star and not so nice review.
The 50% refund is a big problem, you can get that 50% easy, but if it ia 100% junk you have to do the send back or document the trouble perilous journey where you no longer have the product and risk going over the refund date.
There are too many options and none of them are good for the buyer. My main issue was that they wanted multiple videos of them not working and none of the videos would upload. Aliexpress was the biggest part of the problem as they kept responding with “try again tomorrow.” After a week of that I gave up.
Oh, well! Lesson learned!
I think I may have purchased dud MCUs supposedly PIC16F72 in a sale from a surplus outfit (not in China or Alibaba) on one occasion several years ago. I designed several bits of equipment and left the hardware in mothballs until recently when I completed the programs to run on them. Horror of horrors – neither PICKit I have could connect to several of them. The rest are still in the tubes. The PICKit programmers appear to be working correctly – I could program other PIC micros just fine. Luckily I managed to purchase the real McCoy from Microchip earlier today. And I did not have to wait a year to get them as they happened to be in stock. Lucky – my projects are saved from certain doom.