EEVblog Electronics Community Forum
Electronics => Microcontrollers => Topic started by: legacy on June 13, 2017, 08:54:53 am
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So, last week I bought a basket of battery from china, declared 4600 mAh, found they actually are 700mAh :palm: :palm: :palm:
And before of this "good deal", I had bought a basked of SD cards of 4 Giga each, at that time four Giga was expensive (some years ago, 4Gbyte SD were rare). I paid 1/3 of the price, but when they arrived ... I found they were 512 Mega because for Chinese seller meant Giba-bit instead of Giba-byte :palm: :palm: :palm:
So, I want to collect these interesting chinese fakes
Who doesn't remember the 328-fake saga ?
part1 (https://www.sparkfun.com/news/350), ATmega Slugs
part2 (https://www.sparkfun.com/news/364), Revisiting the Counterfeit ATMega328s
part3 (https://www.sparkfun.com/news/384), Dear ON Semiconductor
part4 (https://www.sparkfun.com/news/395), Fake ICs Identified
And the FTDI-FT232RL-real-vs-fake-supereal (https://zeptobars.com/en/read/FTDI-FT232RL-real-vs-fake-supereal) :D
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"So, last week I bought a basket of battery from china, declared 4600 mAh, found they actually are 700mAh"
Yeah I went through that a few years ago. AA NiMHs... You'll be lucky to get that 700mAh maybe five times out of them. If you can get them to keep that charge for more than a few hours.... :-DD
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LOL :-DD
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Great posting good to warn others apart from the amusement/amasement factor. I myself fell for fake onsemi schottky diodes from china many years ago, since then for me its a no buy zone for most things, I even recently fell foul of fake water pumps!! There a generic body with different (encapsulated) innards for different voltages and powers, they simply stick high value labels on low value pumps grrrrr
I guess everybody has seen the picture of a big can electrolytic opened up to reveil a dinky little guy wired across the terminals inside :wtf:
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"So, last week I bought a basket of battery from china, declared 4600 mAh, found they actually are 700mAh"
Yeah I went through that a few years ago. AA NiMHs... You'll be lucky to get that 700mAh maybe five times out of them. If you can get them to keep that charge for more than a few hours.... :-DD
There is no error, 4600mAh is all you can get from these batteries over their lifetime ;) .
Cheers
Alex
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Time to go easy on the 'Buy It Now' click click thing, guys
Do some research before the alcohol kicks in :-+
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Learned it the hard way as well |O - got remarked Spartan 6 FPGAs last month in CSG324 package - the surface texture of package is considerably different (croaser) than original, font of the markings contains one mistake, also the laser ablated marking is bit thicker. I'm yet to solder them on proto boards and see how it reports itself over JTAG, but beware from buying anything expensive from chineese component brookers.
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What are you guys doing to avoid getting ripped off, aside from not shopping on these sites anymore? I've been going by the seller ratings, item ratings, and customer pictures vs seller pictures, but I'm not sure that's enough. I usually shop for stuff that's generic enough that it doesn't make sense to counterfeit, but I did get some LM317Ts that were crazy cheap (here (https://www.aliexpress.com/item/Free-shipping-10PCS-LM317-LM317T-Voltage-Regulator-1-2V-to-37V-1-5A-new-and-original/32647898323.html)). Hopefully they turn out OK.
Does the seller/website/credit card refund the money when you tell them it's fake? If so, how much of a hassle is it?
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What are you guys doing to avoid getting ripped off, aside from not shopping on these sites anymore?
Fraudsters prey on idiots who who think price is the only thing that matters and that the adage "if it sounds too good to be true..." doesn't apply to them.
I buy 'vintage' chips from eBay because that is the only way to get them. Most of the time they are legitimate, even if remarked and sold as 'new'. I also buy generic new parts such as resistors, LEDs, connectors etc. for my DIY projects - but not ICs (too hard to verify whether they are up to spec). I only buy from sellers who specialize in electronic parts and have reputations higher than 99%.
I think the majority of these vendors are relatively honest. Those who have a good reputation want to keep it, so if you are ripped off then they are too. I have only given bad feedback twice, and both times the vendor offered to refund me.
When I need guaranteed genuine parts I buy from reputable suppliers such Farnell or Digikey. I also buy parts from the local Jaycar store because it's convenient - but they sell the same crap that I can get on eBay for 1/10th the price!
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What format was the battery?
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Maybe we can add the LED GU10 halogen replacements I got on eBay. They work, but they have brightness variations unit to unit, and slightly off color temperature. Some are bluish, some more red.
But for lighting up the entrance for a few minutes, they're OK. One day, one of them got real dim. I took it apart, it's 4 LEDs in series. One of the LEDs went into some weird negative resistance failure mode, I could get the single LED to light up slowly but as I ramped up the voltage it got darker and started flickering like a 1960s ballast stuck in relighting mode.
This caused the entire string of LEDs to go bananas. But the other 3 LEDs were still OK so I chucked the Royer converter base and kept the 3 chips and the lens, they light up like NUTS on the lab supply, it's a great extra light for looking at stuff.
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Here we go. I added that green wire to replace that wonky LED. I shoulda videoed that dumb LED, it was fascinating because I don't know what happened to it for it to act like that.
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100+ QC failed fpgas.
Only about 4 worked. And, this is after I had them assembled. Swapping with baked out "fresh" ones ruled out moisture problems and reflow failures - the chips were just bad.
Most did not even respond to JTAG. Some did, but one of the PLLs did not work, or there was a dead IO pin.
My best guess is that Altera normally do another post-packaging QC check to ensure functionality, and these were binned. They are not remaked or fake, but if you look closely on the corners the edges are sometimes very slightly chipped or rounded. Like they were jumbled around in a trash bin.
Seller was the chinese company Liheng Technology IC.
The other chips I bought from them worked fine. Also, it was the very first purchase. Usually the chinese don't try to rip you off until after a few orders where everything goes too perfectly. I'd guess their upstream supplier was the one that sold them these.
(http://retroactive.be/img/i/ra5824eff8a428e54e2.jpg)
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I bought an uBlox NEO M8N from Ebay the other day.
Powers up, spits out NMEA and responds to uBlox binary protocol (because it is recognized by the uBlox software tool). Update rates can also be reconfigured etc.
Until you try to use some of the more advanced features or update firmware -- no dice!
Then after some googling.. of course other peoples have had the same trouble:
https://forum.u-blox.com/index.php?qa=2365&qa_1=does-this-look-like-a-genuine-ublox-device
Luckily I got a refund from the seller.
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I wouldn't be so sure that very cheap / generic components are unlikely to be counterfeit. I have seen 1/4 W axial metal film resistors that turned out to be carbon film (temperature coefficient was way too high for metal film).
https://www.eevblog.com/forum/chat/source-for-resistor-kits/ (https://www.eevblog.com/forum/chat/source-for-resistor-kits/)
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100+ QC failed fpgas.
I have to inform that it has just happened to me too with my last purchase: qty=10 of defective Spartan2 units found in my basket. Bought from a china seller on eBay as they are obsolete parts. I spent the whole day testing, chips get identified by jtag with the correct PN, but once programmed their behavior is not as expected from the datasheet. I can say it because I also have two Spartan2 units bought some years ago when they were available on a local shop. They have the same part number. Comparing, the fist annoying thing is: units don't seem to be 5V tolerant, as they work at 3.3V but they show a strange behavior when used at 5V.
Also it seems there is a problem with the clock_in as more than 10Mhz bricks the chip (even if used at 3.3V) :wtf: :wtf: :wtf:
I am trying to have a refund but the main problem is ... one month and half gone for the shipping and customs clearance, and 120 Euro + 28 euro of customs trashed.
What. The. Freak :palm: :palm: :palm: :palm:
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Re; Vintage components.
Unfortunately, sometimes the only ones available are those found on Ebay.
Not everything is bad, however.
I've purchased over the years many things, including a pair of Dekatron tubes from the Ukraine just last month (they were OK), and only once I've been fleeced.
I've been lucky, I guess.
Anyways, the old adage, Caveat Emptor, applies.
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I've had good luck with Chinese sources on Ebay -for used Rubidium frequency references, GPS receivers and antennas - but I was careful to buy only from top-rated sellers.
I've bought used test equipment on Ebay (Agilent, Tektronix), but only from top-rated US and EU sellers. It's a cliche, but it's a cliche for a reason: if it's too good to be true, it probably is.
For components that need to be reliable (about 100% of my needs), I stick to mainstream distributors like Digi-key, Mouser, Element14, etc. Asian supply chains are rife with counterfeit parts, so I rely on the major distributors to police their own stock. Fake, unreliable parts simply cost me too much, in time and money.
Someone mentioned Jaycar. Recently, I walked into a Jaycar store looking for D-sub connectors, for a test and measurement setup. The quality on offer was so bad that I walked out without buying anything, price be damned. I refuse to use <expletive> <expletive> components in anything I do.
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For components that need to be reliable (about 100% of my needs), I stick to mainstream distributors like Digi-key, Mouser, Element14
Yup, but I can't find Spartan2, I specifically need 5V tolerant fpga
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If reliability is important, than I would suggest a redesign with still active parts. For example, the XC9500XL CPLD series is still available and could be used as a 5V-tolerant buffer for the FPGA (depending on the exact interface requirements). Or use one of the simple level translation ICs. Xilinix even has an appnote (https://www.xilinx.com/support/documentation/application_notes/xapp429.pdf) with some level translation solutions. Or design the other end to use more modern I/O voltages.
Even if the components seem to pass a cursory test (i.e. not blow up when exposed to 5V), how would you know they are not rejects that failed QA for some reason?
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Learned it the hard way as well |O - got remarked Spartan 6 FPGAs last month in CSG324 package - the surface texture of package is considerably different (coarser) than original, font of the markings contains one mistake, also the laser ablated marking is bit thicker.
Do they actually sand-blast the chips to get rid of the original markings, then re-label them? Sure looks like it, from the coarse texture in your photo!
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Black chips are just gambling.
So, mine (defective spartan2) were probably black-chips.
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XC9500XL CPLD series is still available and could be used as a 5V-tolerant buffer for the FPGA
Yup, this is a good trick, I know it works as it has been used by DangerousPrototypes, but I need to access a large bus with 26bit address and 32bit data lines, plus other 4 control lines, therefore I'd like to make the PCB the simplest.