• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Fake parts

Willen

Well-Known Member
#21
For fan's dimmer, I bought 4 TRICs in near city shop. All of them were shorted built-in. I complained and seller checked its pack, he also got all of them shorted. He avoid to take return my fake fours. Now he is selling his fake bag!
 

unclejed613

Well-Known Member
#23
the bottom op amp die looks like an LM1458, definitely the layout and thermal design National Semiconductor use in their op amps.
 
#24
I bought a bunch of EBay Asian LEDs, and wondered why none of them worked. Took me awhile to realise that the standard markings, EG: long lead indicated Positive, in this case indicated Negative.
...oh well
 

gophert

Active Member
#25
I bought a bunch of EBay Asian LEDs, and wondered why none of them worked. Took me awhile to realise that the standard markings, EG: long lead indicated Positive, in this case indicated Negative.
...oh well
The title of the thread is "Fake Parts", I'm not sure unconventional pin assignment qualifies as fake. What did the datasheet say about pin assignments and length?
 

schmitt trigger

Well-Known Member
#26
I bought a bunch of EBay Asian LEDs, and wondered why none of them worked. Took me awhile to realise that the standard markings, EG: long lead indicated Positive, in this case indicated Negative.
...oh well
Factory rejects, perhaps ?
 

unclejed613

Well-Known Member
#27

unclejed613

Well-Known Member
#29
how do you say "you got snookered" in russian? is that sand, or some kind of ceramic dust?

a few years back, i was in a discussion about counterfeit parts, and the question came up "besides money, what other possible motivation is there for counterfeiting parts?" one of the hypothetical answers was "economic warfare". suppose for a moment that a particular country (Alphastan) might want to weaken the economy of their neighboring country(Bravolia). Bravolia's largest industry produces power transistors, and nets $100B per year, of which Bravolia uses $20B for military spending. Alphastan wants to invade Bravolia and take over their lucrative manufacturing venture, but Alphastan's economy is in the toilet, and their military hardware consists of aging hand-me-downs from the Cold War. Alphastan does have $2B to spend in their limited budget for covert operations against Bravolia. Alphastan finds a parts broker in Malaysia that has 10 billion power transistors available for less than a penny each, that look similar to Bravolia's lucrative product, but are factory seconds from a fab in Malaysia. so, Alphastan buys the parts, and opens a factory that shaves off the Malaysian part number, and prints the Bravolian part number and fab logo on the parts. after all of the parts have been processed, Alphastan contacts parts brokers in the far east, offering to sell the transistors for 90% of the going price Bravolia charges. Some of the brokers can't resist the discount and buy up all of Alphastan's stock, and sell them to importers for the same price as the genuine Bravolian parts. now there is a glut in the market, which forces Bravolia to reduce their price, and things are not going to get better for Bravolia... as the counterfeit parts hit the market, and begin getting used in the manufacture of various electronic devices, the counterfeits begin failing in large numbers. most users of the parts begin distrusting Bravolian semiconductors, and look elsewhere for parts that are reliable. Bravolian semiconductor sales drop to a trickle, and now Bravolia's primary export has very few buyers, and their profits drop from $100B, to $10B or less. the Bravolian economy soon tanks, and many businesses inside the country begin to fail. meanwhile Alphastan has netted $90B, and can spend most of that on military hardware, as well as temporarily relieving their poor economy. Alphastan won't need to do another parts counterfeiting coup, because, before their windfall peters out, they will invade Bravolia, and take over Bravolia's manufacturing base.

i realize the scenario is a gross oversimplification of how economic warfare works, but the basic elements are in there....
 

gary350

Well-Known Member
#30
Most of what I have bought from china has been good for the exception of 2 things. I bought rechargeable AA batteries that felt very light weight compared to old batteries they would not hold a charge much longer than the batteries I was replacing. I complained and got a full refund. I ordered more AA batteries from different seller in china again light weight batteries that will not hold a charge longer than old batteries I am replacing. This seller would not give a refund. I took the batteries apart they all looked like an unmarked AAA battery inside of a AA battery body.

I ordered 10 bridge rectifiers rated 100 volts 25 amps. First 1 went up in smoke on 15v 20a within 20 seconds attached to a very large aluminum heat sink. Second 1 smoked at 15v 15a about 35 seconds on same heat sink. Now I have 6 bridge rectifiers in parallel on a 4" wide x 9" long aluminum heat sink 2" thick. I have increased the voltage & amps to 21 volt 35 amps and it works good for 2 minutes each time. Rectifier has been working good for 4 years. I still do not trust it to run very long it is only pulling about 6 amps through each bridge rectifier. I have determined the problem is heat transfer inside the bridge rectifier body it is not able to transfer heat to the metal case, center gets hot and explodes before metal case ever gets warm.
 

dr pepper

Well-Known Member
Most Helpful Member
#31
I just got some Lm35's from Rs Nige, you'll be glad to know they work perfectly.
There are diffo versions, mine are 922- 4836.
 

Nigel Goodwin

Super Moderator
Most Helpful Member
Thread starter #32
I just got some Lm35's from Rs Nige, you'll be glad to know they work perfectly.
There are diffo versions, mine are 922- 4836.
RS have a confusing variety of part numbers, often just the same part in different packaging (such as in a tube, or in bags) - it makes life very confusing :D

I had five tiny 8 pin SM chips come in a tube the other week, but the tube was half a metre long and needed a large box to contain it :D I was wondering what had arrived, as I hadn't ordered anything large.
 

dr pepper

Well-Known Member
Most Helpful Member
#33
I just got some superglue, the cosh datasheet was much bigger & heavier than the glue itself.
 

Nigel Goodwin

Super Moderator
Most Helpful Member
Thread starter #34
I just got some superglue, the cosh datasheet was much bigger & heavier than the glue itself.
Back where I used to work we had the factory inspector turn up one day, she was a stunningly attractive young lady, and was over the moon because I had a box file with all the COSH datasheets (and sundry other stuff) stored in it. I avoided telling her that I just 'chuck them in the file' and never look at them :D
 

dr pepper

Well-Known Member
Most Helpful Member
#35
That is exactly what I do.
I had an older but good looking lady in the other day, a rep, and I treat her as though she knew little about control systems and data comms, turned out she's very well clued up and made me look puny.
Serves me right I spose.
 

Willen

Well-Known Member
#36
I recently bought a dimmer to control fan. But just got bad smoke from the non-sense dimmer. This is nonsense because look at the triac pins used in the dimmer. :D

Now the DIAC feeder resistor and the TRIAC are damaged. TRIAC shows the 1st (terminal) and 3rd (gate) pins shorted. Is it mormal to get that kind of short while powering the circuit withh such fool wiring? Or the TRIAC itself was built-in fake? Few months ago in a shop I have found whole bag og BT136 shorted 1st (terminal) and 3rd (gate) pins. The one inside the fool dimmer looks pretty similar like these fake BT136.
 

Attachments

Last edited:
#37
Well I've two batches of bogus LM35's from China, neither batch works
I'm starting to think as well that China isn't best in producing complex IC's. When I order simple logic IC's online (particularly those that start with 74HC), every one I tested is OK. But I did order some microcontrollers and eeproms from China one time, and that purchase was so horrible, I had to get on the phone twice with Ebay just to get a refund. Also, many of those chips looked as if they were sanded down.

Something interesting to search for online is "counterfeit chips" because there is a site that will explain how to identify when a chip is fraudulent.
 

unclejed613

Well-Known Member
#39
I took the batteries apart they all looked like an unmarked AAA battery inside of a AA battery body.
i wonder if they're cells out of a 9V battery?... actually i think the cells in a 9V battery are even smaller than AAA size
 

dr pepper

Well-Known Member
Most Helpful Member
#40
Unc I think pp3 batteries the ones with individual cells in anyway use aaaa's, which you can also buy separately.
 

Latest threads

EE World Online Articles

Loading

 
Top