fake transistors ! never - Page 1
Forum section: electronics / general

author: siliconmix
author_rank: Frequent Contributor
timestamp: March 29, 2012, 07:59:33 pm
content: good experiment

author: vk6zgo
author_rank: Super Contributor
timestamp: March 30, 2012, 02:06:49 am
content: I'm not wildly impressed by the bloke with the acetone.It would be more convincing if he showed that youcouldn'tremove the label from a genuine device as a "control"Acetone is pretty savage,& the labelling on even genuine devices is bloody awful,so my bet is it would still have the same effect.That,coupled with pouring the acetone into a plastic container,& spilling the stuff all over the desk,doesn't do a lot for his credibility!With the test of transistors in the CB PA stage,several things come to mind:I'm a little leery of just popping PA transistors in higgledy piggledy.Perhaps the tuning of the PA needs tweaking with the "fakes",(although 27 MHz CBs are fairly broadband).&How much of the 4 watts with the good transistors is 27 MHz,& how much is harmonics?But then,I'm just a over critical old sod!

author: siliconmix
author_rank: Frequent Contributor
timestamp: March 30, 2012, 05:21:41 am
content: your are right vk on all .the harmonics should have been filtered out though.i bet the good one got hot without a hsink.i just thought it was a good try

author: amspire
author_rank: Super Contributor
timestamp: March 30, 2012, 05:52:37 am
content: Quote from: vk6zgo on March 30, 2012, 02:06:49 amI always thought the hardest part of making a fake IC is coming up with a working silicon device that worked something like the original.Clearly that bit is dead easy. Now finding acetone resistant ink - obviously impossible for the fakers.Not to impressed with that strange fake IC detector box either. It didn't try and test the IC functionality - it just measured some kind of characteristic properties of each pin.Richard.

author: siliconmix
author_rank: Frequent Contributor
timestamp: March 30, 2012, 05:56:10 am
content: i haven't any acetone. could one of you good people that has some try it on a good ic ?

author: amspire
author_rank: Super Contributor
timestamp: March 30, 2012, 06:28:51 am
content: Quote from: siliconmix on March 30, 2012, 05:56:10 amI just tried it on a ST voltage regulator and a Motorola MOSFET. The print didn't come off easily, but there was a little ink on the cotton bud. If I kept rubbing long enough, the ink probably would come off completely.But then again, it might just prove that both parts are fake. They both did come from a reputable distributor.I only have one part I know absolutely cannot possibly be a fake - an OKI M85C154 chip with a piggyback eprom socket on top to allow development of OTP 8051 processor type chips and its ink was totally resistant to acetone. That was ink on gold plate metal - not ink on epoxy. This is the only IC I have that I received by hand directly from the manufacturer.Richard.

author: siliconmix
author_rank: Frequent Contributor
timestamp: March 30, 2012, 06:33:37 am
content: nice work amps .the plot thickens .what about in your junk box a pcb from a working branded make? acetone is on my shopping list

author: steve_w
author_rank: Regular Contributor
timestamp: March 30, 2012, 07:12:29 am
content: Make sure you get a MSDS and follow all safety precautions, wouldn't want any accidents :-)

author: G7PSK
author_rank: Super Contributor
timestamp: March 30, 2012, 07:26:49 am
content: I always thought the hardest part of making a fake IC is coming up with a working silicon device that worked something like the original.Clearly that bit is dead easy. Now finding acetone resistant ink - obviously impossible for the fakers.Richard.Many of the fakes are not fakes as such, The original manufactures rejects have been obtained and then badge'd and sold as originals full spec.

author: amspire
author_rank: Super Contributor
timestamp: March 30, 2012, 08:01:34 am
content: Quote from: G7PSK on March 30, 2012, 07:26:49 amThat would mean they would probably fully pass "Fake Detector" that siliconmix linked to. The pins would look exactly like the pins on a non-rejected IC.https://www.eevblog.com/forum/general-chat/fake-transistors-!-never/msg101132/#msg101132Some of the IC's rubbed with acetone had black coming off which sounds like the previous markings were covered up. I don't know why you would get black off otherwise. I guess one way of faking ICs is to sell a cheap low spec part as an expensive high spec part.Richard.

author: david77
author_rank: Frequent Contributor
timestamp: March 30, 2012, 08:59:01 am
content: I'd think the black stuff would be plastic from the IC's case. Acetone would probably even attack the plastic.I once got a couple of MJ15025 and MJ15024's that were supposed to be genuine Motorola parts. The print on the case was a bit odd´, but I ignored that. I got suspicious when I screwed the things onto their heatsinks and on thightening the screws they all popped off the can part of the TO-3 case. They all went "PING" and threw their hats at me. Obviously the base plates were slightly bent and screwing it on a plane surface stressed it so much that the welding/glue (?) cracked.That revealed a die far too small for the power that these transistors should be able to handle.I was using them in a beefy +/-15V power supply and the fake parts didn't even come close to the specs of the real parts, I think they all gave up at around 4A.I never ordered from that supplier again

author: siliconmix
author_rank: Frequent Contributor
timestamp: March 30, 2012, 09:00:54 am
content: isn't acetone kept in plastic bottles e.g nail varnish remover

author: david77
author_rank: Frequent Contributor
timestamp: March 30, 2012, 09:07:00 am
content: I've only ever seen acetone in tin cans or glass bottles.

author: siliconmix
author_rank: Frequent Contributor
timestamp: March 30, 2012, 09:08:44 am
content: it must be a small percentage of acetone then .forget i said it

author: david77
author_rank: Frequent Contributor
timestamp: March 30, 2012, 09:17:34 am
content: As a boy I once put some Acetone into a plastic yoghurt pot to store it. When I later went to use it again the Acetone was gone and the molten yoghurt pot stuck to the shelf. That tought me something.

author: T4P
author_rank: Super Contributor
timestamp: March 30, 2012, 05:40:47 pm
content: Quote from: siliconmix on March 30, 2012, 09:00:54 amPlastic bottle ones are not so reactive ...The ones in glass bottles are rather powerrrrrrrrrrrrrful

author: bilko
author_rank: Frequent Contributor
timestamp: March 30, 2012, 05:52:22 pm
content: so, anyone found the original markings underneath the fake print ?

author: westfw
author_rank: Super Contributor
timestamp: March 30, 2012, 11:06:57 pm
content: Acetone dissolves some plastics (polystyrene in particular) but others are pretty immune (polyethylene, PET.) And yes, nail polish remover is usually mostly acetone and usually comes in plastic bottles. I moved my can of acetone into old PET soda bottles because the cap seals a lot better, and they held up fine.IC packages are usually cured epoxy, which is pretty immune to most solvents. See some of the reports on removing it during reverse-engineering. A lot of older IC markings are also epoxy-based inks and should be mostly solvent-immune. I think most modern chips are laser-engraved...

author: SeanB
author_rank: Super Contributor
timestamp: March 31, 2012, 11:00:59 am
content: Many jellybean parts are screen printed ( screen is a cheap and durable item, and will do millions of parts before it needs repair) with a solvent based ink. Solvent can be anything from IPA to MEK ( lovely stuff, degreases anything including skin). Acetone removes this, but so will cane spirit and rubbing.Most IC packages can only be dissolved by using a witches brew of solvents, and it comes in a glass bottle, with a top that will not survive long before dissolving in the vapour. Certain epoxy compounds only can be removed with nitric acid or aqua regia. Leaves the chip bare, with all metallisation that has not been nitrided or coated missing.

author: Greate
author_rank: Contributor
timestamp: March 31, 2012, 03:45:49 pm
content: It may not be 100% fake but could be fraud.It is so expensive to start manufacturing fake semiconductor device that making it legit will be not much of an expense. It could have been the phony sellers thhhat they tend to change the label of a underdog replacement part to put the labe of a high prize class apart to make more money.Sent from my A100 using Tapatalk

author: G7PSK
author_rank: Super Contributor
timestamp: March 31, 2012, 04:00:05 pm
content: Just checked the wife's nail varnish remover, No acetone in it, Ingredients list says Ethyl acetate,Isopropanol, Water and Glycerine. Except that it does not say water but uses Aqua instead why the cosmetic industry thinks aqua sounds better than water I cannot think.As I said before not fakes, Rejects that are sold of cheap or even scraped by the manufacturer as substandard but will still work for some applications, Reprinted to look like the top spec item.

author: sonicj
author_rank: Frequent Contributor
timestamp: March 31, 2012, 05:35:57 pm
content: Sparkfun bought 1500 ATmega328s from a grey source back when they were nearly impossible to find. Long story short, the chips didn't work and they decided to investigate. Purdy interesting reads....ATmega SlugsRevisiting the Counterfeit ATMega328sDear ON SemiconductorFake ICs Identified

author: Rufus
author_rank: Super Contributor
timestamp: March 31, 2012, 06:11:51 pm
content: Quote from: sonicj on March 31, 2012, 05:35:57 pmFor the worst Chinese fakers having approximately the right package is the only requirement for chips to be re-marked as whatever someone wants to buy. They sell non-functional fakes to each other as well, they will screw anyone they can.

author: steve_w
author_rank: Regular Contributor
timestamp: April 01, 2012, 12:01:56 am
content: Hey Sonic,Great read, thanks for sharing

author: siliconmix
author_rank: Frequent Contributor
timestamp: April 01, 2012, 06:00:52 pm
content: i've been searching for a chinese seller on ebay that has negative feedback for components that are fake or didn't work.i haven't found any yet.i have bought from china and haven'thad a problem.are there buyers buying bulk from china and selling on without knowing that some are going to be fakes.

author: PStevenson
author_rank: Regular Contributor
timestamp: April 01, 2012, 11:26:37 pm
content: Quote from: siliconmix on April 01, 2012, 06:00:52 pmwhenever I get parts that don't work it will be say 4 or 5 in a batch of 100 and I always get in contact and make them send me a replacement set of however many didn't work, I think this is the best method because if everyone started doing it then they may do a bit of testing before risking losing money sending replacements out. I learnt very early on to build up a temporary circuit to test whatever I'm buying and then just spend a while going through each onebut if you think about it people will only leave feedback based on the time it took to get there so even though some of their sellers could be bad you'd never know. it might be a good thread to start - Grey Market Thread" which sellers sell good stuff.if anyone starts that thread I will give you the verdict on the 200 LM358s I've got coming soon

author: bfritz
author_rank: Regular Contributor
timestamp: April 02, 2012, 03:50:34 am
content: The bodies of IC's for as long as I've been involved (25 years) have been immune to any solvent I know of. Whenever I've needed to decap an IC, it has involved a strong acid.The markings on IC's have either been pad printed epoxy based inks, or in the past 15 years or so are almost exclusively laser printed. (Basically etching the encapsulantion with the laser.) In either case, a solvent will not remove the printing.

author: siliconmix
author_rank: Frequent Contributor
timestamp: April 02, 2012, 06:23:51 am
content: Quote from: PStevenson on April 01, 2012, 11:26:37 pmyes good idea .there you go it's your baby. "Grey Market Thread" .i like it.

author: amyk
author_rank: Super Contributor
timestamp: April 02, 2012, 12:02:37 pm
content: Quote from: Rufus on March 31, 2012, 06:11:51 pmSometimes they don't even have the right package....http://www.bunniestudios.com/blog/?p=208

author: LEECH666
author_rank: Frequent Contributor
timestamp: April 02, 2012, 12:53:41 pm
content: Just shot this video. Beware: Might be a bit loud, full of bad grammar and german accent.When I say "black print" in the video I actually mean't "black plastic".Cheers from ZEH GERMANZ,Florian//EDIT: Apparently the part marking is laser edged, as mentioned before. I though the markings were actually printed on. Guess I was wrong.

author: steve_w
author_rank: Regular Contributor
timestamp: April 02, 2012, 09:30:27 pm
content: good post, don't worry I understood everything perfectly.regardsSW

author: mzacharias
author_rank: Frequent Contributor
timestamp: April 03, 2012, 03:00:38 am
content: OK, well, there's this bi-amped Advent powered loudspeaker. The tweeter amp is blown. The outputs are 2N6284 and 2N6287 Darlington TO-3 package transistors. Pretty obscure these days. The schematic info also included NTE subs but those were nearly 20.00 each, with no guarantee in my mind as to quality, etc.So I ordered the 2N numbers from MCM. More like 5.00 each and I've had pretty good luck with MCM lately. When I received them, they were mismatched vendor markings, and one looked like cheap crap so I tested them right away. Actually, the one that looked like crap was OK, but the "2N6287" with Thomson ST markings was SHORTED emitter-base right out of the chute. Icalled MCM - "Oh, gee we're sorry" and they sent me another, no need to return the bad one.So I cut it open. It wasn't even a Darlington, just a single emitter base junction and the die was only 2mm instead of 5mm. There was a visible gash across the die, so obviously the thing was never tested in manufacture.So I receive the replacement. I test it, and this one is OPEN emitter base. Once again I call MCM, got credit and no need to return them, so I cut this one open as well. Here's the fun part:The transistor case was EMPTY. No die, no leads, just an empty case. I've emailed pics to MCM.With a little more research I was able to get the Onsemi MJ versions fromAllied Electronics, so all is well, and the repair worked out OK.Mark Z.

author: david77
author_rank: Frequent Contributor
timestamp: April 03, 2012, 06:49:53 am
content: Quote from: mzacharias on April 03, 2012, 03:00:38 amI'd say the manufacturer tested them all right and decided to dump them in the rejects bin to be disposed of.Somebody got hold of the rejects, labeled them and sold them on.Does anybody know what percentage of a semiconductor manufacturers production ends up in the rubbish bin? Ballpark figure?For somebody to go to the trouble of selling rejects on as fakes it must be quite an amount, I'd think.

author: siliconmix
author_rank: Frequent Contributor
timestamp: April 03, 2012, 07:02:36 am
content: thats nasty

author: T4P
author_rank: Super Contributor
timestamp: April 03, 2012, 09:29:43 am
content: Jeez . MCM must have been supplied with fake parts and didn't check . In short , they bungled up .Quote from: david77 on April 03, 2012, 06:49:53 amI would say 10% maybe . 10% is a large amount still .

author: amyk
author_rank: Super Contributor
timestamp: April 03, 2012, 11:47:17 am
content: That empty case looks like it never had a die bonded to it.Some shady reseller might've gotten a huge lot of surplus TO-3 cases and decided to sell them as whatever parts customers were asking for...

author: PStevenson
author_rank: Regular Contributor
timestamp: April 03, 2012, 02:15:14 pm
content: haha put a 2n5088 or something in it - glue it down with hot snot and then sell it to an audiophile as a "special-double-package-to restrict-vibration-keeping-warmth-and-transparency" transistor

author: T4P
author_rank: Super Contributor
timestamp: April 03, 2012, 04:43:56 pm
content: Quote from: PStevenson on April 03, 2012, 02:15:14 pmAnd market it at 20000$and run away once you get the money

author: bfritz
author_rank: Regular Contributor
timestamp: April 08, 2012, 03:39:35 am
content: Quote from: david77 on April 03, 2012, 06:49:53 amFor a good manufacturer, with a quality process, the rejects seem to usually be in the under 1% area. But, that would be entire waste. For a complex IC, it would likely have some test / trim done at wafer probe, so die that fail there, would never get packaged. I remember a number well under 0.5% for most parts, and this includes things like bent and damaged pins, marking system failures, etc. So, for a high running part of say 10 million a year, 0.5% is 50,000 parts.At the manufacturer I worked for, when the bin was removed from the tester, the shift supervisor was required to be present, and they both logged the bad parts, and disposed of them in a special bin that got sealed. There were procedures where the bin was weighed and the weight checked against calculations for the number of bad parts in the log. Yes, it can be quite profitable for those smuggling out the parts, and actually costs the IC manufacturers a lot of money, as we ended up tracking down these grey market goods and their sources.