Fake transistors - Page 1
Forum section: electronics / beginners

author: sureshot
author_rank: Regular Contributor
timestamp: July 04, 2018, 12:14:53 pm
content: This might have been mentioned before, I'm not sure. Having bought voltage regulators from china that where fake, i don't bother with that anymore. I've got a trusted handful of ebay sellers that have NOS new old stock. But i thought I'd try a seller with some transistors that where home based here in the UK. They arrived today and check out fine doing a test with the diode function, but there not looking like the normal finish to me. The tab is more shiny, i filed off a little of the plating, sure enough its copper. But they just seem not quite right. I don't have a camera handy at the moment, but will put up a comparison later between legit transistor, and the one's I'm unsure about. I'm tempted to do a distructive test, but something is telling me to bread board one and test it under load.I knew i might be buying fake, but at £1.00 each it was worth a gamble. The devices are TIP36C power transistors. I was hoping to get a bargain by buying a small quantity first. Then a few more if they checked out good. The voltage regulators from china where lm317k's i opened a fake one and could see the difference immediately, they couldn't even handle 500mA of current. Anyone else been stung with fake transistors. Thoughts appreciated.

author: Gyro
author_rank: Super Contributor
timestamp: July 04, 2018, 12:34:36 pm
content: Yes, fake transistors do exit, and in large quantities from certain locations (Ahem). It's much less likely from a genuine UK registered seller though. The simplest way to tell is to look at the seller's other items. From the selection it's usually pretty easy to judge whether they are selling genuine NOS / overstock or importing fakes.

author: sureshot
author_rank: Regular Contributor
timestamp: July 04, 2018, 12:43:35 pm
content: Yes i always checkbout the seller carefully, just to judge if its worth the gamble. This seller has 100% feeback and has sold quite a few, no negatives to speak of.Below is the known good transistor on the left and the suspect transistor on the right. Both show virtually the same with multimeter diode check.

author: Gyro
author_rank: Super Contributor
timestamp: July 04, 2018, 01:06:37 pm
content: Hmm, I see what you mean, it looks 'tinned' rather than plated. I wonder if those score lines on the back of the pins could be where new leads have been butt welded? I'm probably just being suspicious though!

author: MK14
author_rank: Super Contributor
timestamp: July 04, 2018, 01:19:16 pm
content: One of the problems with fake power transistors, is that the silicon die in the transistor will probably be far too small, for the datasheet specification of the device.Hence failures like shown in the video:

author: sureshot
author_rank: Regular Contributor
timestamp: July 04, 2018, 07:00:20 pm
content: That's it really, there's no way of telling straight off the bat. From looking at fakes on the web you can see the die is way smaller than the real device in many pictures. And I guess the readings would check out with a multimeter. It's not until it's put under load that it's true parameters would show. Thanks for the replys and for the video. That seller off eBay had over 25 confirmed sales of that transistor, nothing in the negatives. I checked a lot of other sales with components he's done, again it all looks good. I did file the top edge of the plating just to see if it was copper. That checked out ok. Just have to put them in a circuit and test them. Could be another project.... Test circuit with quick interface change out for npn and pnp devices.

author: Jwillis
author_rank: Super Contributor
timestamp: July 04, 2018, 07:14:59 pm
content: Fakes Fakes Fakes .If your in doubt of where the unit is manufactured ,Look it up. ST Microelectronics has facilities in all over the world including China .Many companies outsource manufacturing around the world . Many of these out sourced facilities will have slightly different equipment for packaging the dies for a component. Just because it looks different does not mean its not genuine .These companies do this to bring costs down for the consumer.I myself have used components from many facilities around the world and have found that the expected tolerance to be the same no matter what the package looks like.Do I support these practices? Of course not .But I won't get into a long economic, political argument for this isn't the place to do it.All I say is if your in doubt its easy to check where something is made.

author: sureshot
author_rank: Regular Contributor
timestamp: July 04, 2018, 10:15:57 pm
content: As I've always purchased from good known sellers, I have had little to nothing in the way of fakes.the UK company's I use are family run and are rock solid. I buy from them because there prices are fair, it supports my country's small businesses, and I've been buying form them for decades. This was only meant to be a taste it and see exercise. It said generic in the listing so I knew what I was buying. It was purely to see if something cheap and cheerful would come up trumps. If not nothing lost.So I will taste them and see. The thread wasn't a " moan about it fiasco " on my part. I've not been hit by fakes much, only once. And that was from China and was voltage regulators. Most semiconductors don't look like cheap bling jewlery. But I'm fine with it, if they work with out failing it's a bonus. It might be wrong to think like this, but I find the lengths the fakers will go to fascinating.

author: MK14
author_rank: Super Contributor
timestamp: July 04, 2018, 10:30:49 pm
content: Quote from: sureshot on July 04, 2018, 10:15:57 pmIn that case, you might be interested in the following thread. Its OP, similarly, bought suspect fake transistors from ebay.They thoroughly examined the transistor(s), both electrically and physically, as you will see if you visit the thread.https://www.eevblog.com/forum/repair/warning-fake-mj16012-transistors-on-ebay/

author: sleemanj
author_rank: Super Contributor
timestamp: July 04, 2018, 10:36:41 pm
content: Shiny legs doesn't necessarily mean fake...https://hackaday.com/2017/07/15/lets-play-spot-the-fake-mosfet/but it's not uncommon for it to mean "recycled part", where it was pulled out of some e-waste, given a bit of a wipe down, solder dip, and sold to you. The legs on the right-hand one at the back look like they have a cut/join, I have heard before of splicing new legs on recycled parts, but I couldn't readily google a reference for that.

author: sureshot
author_rank: Regular Contributor
timestamp: July 04, 2018, 10:48:47 pm
content: Quote from: sleemanj on July 04, 2018, 10:36:41 pmI found that in my web searches, and the hackaday one as well, thanks for posting them though.The two transistors I bought I will try out next. Might be a while, but I will be back with the result, good or bad.

author: thermistor-guy
author_rank: Frequent Contributor
timestamp: July 05, 2018, 01:02:42 am
content: Quote from: sureshot on July 04, 2018, 12:43:35 pmIt's a half-decent copy. Notice with the fake that (a) the logo isn't quite right, and (b) it uses different fonts (e.g. the capital I in TIP, the non-italic e in e3). Give thanks that the frauds in China tend to be lazy about details.

author: wraper
author_rank: Unknown
timestamp: July 05, 2018, 01:22:52 am
content: Quote from: sleemanj on July 04, 2018, 10:36:41 pmThey cut old legs off close to the body and then weld new ones on top. Look from the back strongly suggests that legs were welded. I remember someone posted x-ray pictures of this on the forum.

author: sureshot
author_rank: Regular Contributor
timestamp: July 05, 2018, 11:40:46 am
content: Thanks for the heads up, that xray would be really interesting to see. I'm unsure how to do a distructive test so as not to ruin the end look and see result. I know acids can disolve the package material, but there are tough rules in the UK for such chemicals. And even then I'm not sure if it would destroy the die. I'm happy to do a distructive test on both good transistor and suspect transistor, but would want to get it right. Just thought I'd post this, i just purchased some large snap in capacitors. As i bought a few i thought I'd do a destructive test on one, the seller had one single comment on these in his feedback claiming fake. For all the world it looks fine to me 63 Volts 4700uf snap in electrolytic capacitor. Bargain £1.00 each. Worth sacrificing one capacitor for the war effort on fakes. I was expecting 20uf soldered inside the can, or something similar. But looks fine to me.

author: wraper
author_rank: Unknown
timestamp: July 05, 2018, 11:45:23 am
content: Quote from: sureshot on July 05, 2018, 11:40:46 amSomething like this unlikely to ever happen. They will just put a counterfeit sleeve on some crappy capacitor. Even capacitance most likely would match, voltage rating probably not.BTW, I think I found the listing you bought it from. When buying NOS, you should consider they easily may be 2-3 decades old.

author: wraper
author_rank: Unknown
timestamp: July 05, 2018, 12:37:02 pm
content: Your capacitor seem to be 15 years old.

author: b_force
author_rank: Super Contributor
timestamp: July 05, 2018, 12:45:21 pm
content: ah jeez, fake transistors.They gave me quit some big headaches and sleepless nights.Certain types are notorious of being copied, even being sold from well known distributors.We had a whole production badge that totally failed quality control.We couldn't find the problem until we decapped a few of these transistors.The die was very different, especially MUCH smaller, so they couldn't get the heat away.

author: sureshot
author_rank: Regular Contributor
timestamp: July 05, 2018, 07:02:19 pm
content: The age of the capacitors might be an issue, but it's a gamble worth taking. I've used a lot of old but unused stock before from a family company in Sheffield here in the UK. Semiconductors are generally safe bet, but with capacitors, yes it's the chemical state of the electrolyte. So how to break the case of a TO218 case with out destroying the die ? Just so as the have a look see. I've got a far few tools to attempt it.

author: sureshot
author_rank: Regular Contributor
timestamp: July 05, 2018, 07:07:19 pm
content: Quote from: b_force on July 05, 2018, 12:45:21 pmThat's not good, remember the capacitor fiasco in the pc industry, although it did effect other products as well. Some one in Taiwan stole some electrolyte that was unstable I read at the time. That ended up in the bad capacitors. Not sure that story is 100% accurate.

author: wraper
author_rank: Unknown
timestamp: July 05, 2018, 07:12:46 pm
content: Quote from: sureshot on July 05, 2018, 07:02:19 pmOnly by dissolving plastic by nitric acid, some very nasty stuff. By breaking plastic off the metal you still can see silicon die size despite it breaking.

author: MK14
author_rank: Super Contributor
timestamp: July 05, 2018, 07:34:32 pm
content: Quote from: sureshot on July 05, 2018, 07:07:19 pmMy understanding is ... (probably from the bad caps website)They stole the formula, for making the capacitors. But unfortunately, they stole the wrong formula and/or did not realise, there was more to it. Otherwise the capacitors would only last a rather short time.The rest is history.I.e. There was a mistake in the formula, which they used to copy/clone the capacitors and/or the formula was right, but needed another step/process to make it last a long time. But without that final bit, it did not last very long.Edit: searched for info:https://www.badcaps.net/forum/showthread.php?t=425QuoteOn the other hand, maybe the story is not 100% correct/true and/or telling the full/latest story ?Because...Quote

author: wraper
author_rank: Unknown
timestamp: July 05, 2018, 07:50:49 pm
content: Quote from: MK14 on July 05, 2018, 07:34:32 pmStole or did not steal, Nichicon made their share of bulging low esr capacitors as well (HN and HM series). Nippon chemi-con was affected too (KZG, KZJ).

author: Lionered
author_rank: Contributor
timestamp: July 06, 2018, 10:37:28 am
content: I hope I will now become a victim of fake transistors. It's really terrible to purchase something that will just damage our appliances so it's really important to purchase only from the trusted sources.

author: szoftveres
author_rank: Regular Contributor
timestamp: December 03, 2020, 07:41:18 pm
content: Does anyone recognize the logo of the "assumed" manufacturer of this transistor? It is the main transistor mounted on the back of a cheap adjustable power supply ($27 shipped) so I have no illusions of this transistor being genuine, just curious whose logo they printed on it.https://www.newegg.com/yescom/p/0J6-0032-00042?item=9SIA8SK3S25897&recaptcha=pass

author: wraper
author_rank: Unknown
timestamp: December 03, 2020, 07:48:51 pm
content: Quote from: szoftveres on December 03, 2020, 07:41:18 pmIMHO some small Chinese company logo. Most likely with a very tiny die inside. Are glass insulators blue?

author: bdunham7
author_rank: Super Contributor
timestamp: December 03, 2020, 08:05:53 pm
content: Quote from: sureshot on July 04, 2018, 12:14:53 pmI shouldn't ask, but why are you screwing around with eBay recycled maybe-fakes for a transistor that can be easily sourced from certified sources for less than $2, and under $1 in 1K quantities?

author: amyk
author_rank: Super Contributor
timestamp: December 04, 2020, 03:17:33 am
content: Given that the datecode seems to indicate the 5th week of 1968, I'm willing to bet it's an old recycled part from a long-defunct American company. Looking through lists of old transistor manufacturers may find it.(Yes, 2N3773s existed in 1968.)

author: wraper
author_rank: Unknown
timestamp: December 04, 2020, 03:17:46 am
content: Quote from: blueskull on December 04, 2020, 02:14:27 amIn the past I bought a cheap lab PSU which had two 2N3055 pass transistors marked TRANSUN. Took the lid off, and had the same tiny die and hair thin bond wires you can find in fake crap.

author: wraper
author_rank: Unknown
timestamp: December 04, 2020, 03:22:02 am
content: Quote from: amyk on December 04, 2020, 03:17:33 amIf it was a such date code, it should have had a leading zero. Nor it looks like a part of such age.

author: szoftveres
author_rank: Regular Contributor
timestamp: December 04, 2020, 04:13:53 am
content: That glass thing is blue. And by no means it looks like a 52 yr old transistor.