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Fake parts

Nigel Goodwin

Super Moderator
Most Helpful Member
Thread starter #1
Well I've two batches of bogus LM35's from China, neither batch works - the second batch (of ten) test as NPN transistors, with a gain of 288 or so. The first batch (of four - it was five, but I seem to have lost one?) test as 2 thyristors, 1 transistor (very low gain), and a piece of wire.

Ordered some from RS Components now :D
 
#2
Yes, very frustrating. Took me ages to start buying from China ... and when I finally did ... had a very good run ... but it didn't last. Now I only do it if there's no alternative.

Last week I received some flash memory chips ... and thought I'd done well because they looked new ... and were nicely packaged in factory style sealed strips ... but then when I went to program ... they still had data on them !!!

Fortunately they seemed to program ok ... but still annoying.
 

Mickster

Well-Known Member
#3
If they are from BG, they are pretty good at refunding (as, IIRC, you know from your damaged DS3231 RTC board package wasn't it?)

EDIT: BTW, are they convincingly marked as LM35?
 

Nigel Goodwin

Super Moderator
Most Helpful Member
Thread starter #4
If they are from BG, they are pretty good at refunding (as, IIRC, you know from your damaged DS3231 RTC board package wasn't it?)
The ten recent ones were from Aliexpress, and I've contacted the seller so far. The ones from Banggood I've had a fairly long time, and I can't even find the order listed any more - so I can't really contact them without a reference - it was certainly last year I got them, if not the year before.

EDIT: BTW, are they convincingly marked as LM35?
Yes, they are convincingly marked as LM35 - the new ones from RS have turned up, I've fitted one and it works fine. It's reading 21.2C at this moment :D - it's in free air, but they are for building in Li-Ion battery packs, along with the protection boards that have also arrived now.

Interestingly I tried one on my component tester, and it reads as a PNP transistor, with a low gain of only 13.
 

Mickster

Well-Known Member
#5
Can you take a picture of the parts?
I wonder if they are not actually fakes, but more like rejects which someone dug out of the factory dumpster.
It’s interesting that the component tester reads the good one also as a transistor.
 

Nigel Goodwin

Super Moderator
Most Helpful Member
Thread starter #6
Can you take a picture of the parts?
I wonder if they are not actually fakes, but more like rejects which someone dug out of the factory dumpster.
It’s interesting that the component tester reads the good one also as a transistor.
While it reads it as a 'transistor', it's not a very good one :D

The ten fake LM35's I have test as good usable transistors - the one of the four duff ones that tested as a transistor (but low gain) actually tested as NPN (the real LM35 tested as PNP).

Reject LM35's certainly aren't going to test as good transistors, or thyristors either.
 

tcmtech

Banned
Most Helpful Member
#7
If it's any consolation it not just the electronics industry that suffering from inferior parts and materials seeping into the primary and more reputable secondary supply chains from time to time. :(

My local hydraulics parts dealer had a run of really badly made fittings and hose in the last year. Same with local auto part places and service centers getting loads of really badly made aftermarket and new stock items ( I went through three starters on one vehicle in less than 1000 - 2000 miles) but the bad stuff is oddly hit and miss as they seem to see it. Maybe one, two or three in a batch then nothing for weeks and then odd runs of bad stuff moves to another item or group of items.

I can see the 'dumpster diving' scavenging angle on electronics and small mass produced parts that come from lower end suppliers but when it's bigger higher value components coming from national chain supply centers it seems to be something else.
 

JonSea

Well-Known Member
#8
I have purchased many parts through a couple ebay vendors without any problems. In one order, when one item was left out of the order, those components were sent immediately by express mail when I informed them of the missing parts - no questions asked.

For components, dealing with vendors that sell only components is probably key. They know what they are selling and their continued business relies on favorable comments and ratings. If you buy from a vendor selling sandals, car parts and makeup, chances are they don't know anything about components and the smattering of components they sell were probably purchased at a cheap price from an unknown source.
 

be80be

Well-Known Member
#9
I can't say I had a bad order I guess the worst was some esp2688 there made like 07 but said there 12E the funny thing is there really 12E made on a ESP-07 version of this board
 

Mickster

Well-Known Member
#10
While it reads it as a 'transistor', it's not a very good one :D

The ten fake LM35's I have test as good usable transistors - the one of the four duff ones that tested as a transistor (but low gain) actually tested as NPN (the real LM35 tested as PNP).

Reject LM35's certainly aren't going to test as good transistors, or thyristors either.
Guess the main thing I overlooked was the price. I was thinking "Who the heck is going to go to the trouble of scrubbing and re lazer-etching a TO-92 device, which costs probably a few cents, at negligible possible profit. Why risk getting a bad name as a supplier and burning up valuable contacts/purchasing deals, etc? Probably pulled them out of the rejects bin and hoped they were close enough to kinda work"
Having now seen the price of the LM35 on BG & Ali, compared to jelly bean transistors, I now see why someone would take that risk....Pump out 100,000 & sell them on, shut up shop and set up under a different supplier name.
 
#13
For components, dealing with vendors that sell only components is probably key. They know what they are selling and their continued business relies on favorable comments and ratings. If you buy from a vendor selling sandals, car parts and makeup, chances are they don't know anything about components and the smattering of components they sell were probably purchased at a cheap price from an unknown source.
Very good point. Most times for me it's a matter of take a chance or go without ... but in future when I do have an option, I'll keep that in mind. Thanks.


I started buying from China about 10 years ago after I'd spent a year looking for a particular microprocessor ... and eventually got a quote from a 'mainstream' supplier which was totally outrageous.

They wanted ~$104 each micro ... then $165 freight from the US to Aus.

They could have folded the micros inside a single sheet of paper and posted them for a couple bucks.

I figured I might get ripped off in China with fake parts ... but no worse than being gouged with the price from elsewhere.

Ended up buying them for about $4.50 each ... and have been buying stuff from there ever since.

I've certainly been caught with some duds ... but overall it's been worthwhile.


The only other mistake I made, was using my main email address. I still get swamped with offers from every conceivable place every day ... takes me ages to delete them all ... use a burnable email address if you make general enquiries.
 
#16
How did they get the capacitor cut apart so nicely?
It probably fell apart!

Youtube is a great source of videos on the electronic component counterfeiting industry. It takes you on a tour of some really grubby parts of China - old ladies sitting over a Bunsen burner, melting parts off boards and putting them into test tubes, then throwing the PCB into a river.
 

KeepItSimpleStupid

Well-Known Member
Most Helpful Member
#18
Yep. Counterfeit parts. Looks like I have a dental implant with counterfeit parts. I's been loose 4x in about 5 years. Fortunately, IT APPEARS, to not be the one osteointegrated into the jaw bone. I was told the machined tolerances of the original parts are to 1 micron. Waiting for the restoration to be completed at the lab.
 

tomizett

Active Member
#19
I bought a batch of those all-in-one TO220 flyback controller ICs from Aliexpress or somewhere a while ago - pretty sure they must have been QC rejects from the factory... or a knockoff designed by an apprentice. None worked properly, but all in a different way. Some exploded, some failed to oscillate and some worked - but very badly.
I searched all over that power supply for shorted turns and bad caps before I realised all the ICs where dud! Coughed up for a real one, of course, and it was fine.
 

unclejed613

Well-Known Member
#20
the best way to figure out what's under the hood without doing any physical damage to transistors/ICs, etc... is to x-ray them. this might electrically damage the component, so do any electrical measurements first. while i don't think you can walk into a hospital and ask them to X-ray your parts, it's possible to find MDs and chiropractors that might do it. be ready to pay whatever their normal fee for X-rays are. i've had some experience with counterfeit parts. unfortunately getting a large corporation to find other parts vendors is like trying to turn an aircraft carrier with a canoe paddle. i actually had somebody from corporate call me and ask for a good business reason to change vendors. my answer (knowing that the LAST thing the bean counters wanted was a lawsuit from a customer's house burning down) "they burst into flames when they fail", finally got the point across.
 

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