Check the devices for sanding marks, scratches in one direction will indicate tampering with the markings.
Also check heat spreader thickness, and other dimensions of the package, and the ejector pin locations, some makers used engraved ejector pins.
That will tell you if device is real or not, sometimes the faker changes mark to higher powered device (for example BT136 to BT139).
And to add to the mess, some Japanese companies put 'Japan' only on parts made in Japan, and not on parts made in their factories outside Japan...
Also check heat spreader thickness, and other dimensions of the package, and the ejector pin locations, some makers used engraved ejector pins.
That will tell you if device is real or not, sometimes the faker changes mark to higher powered device (for example BT136 to BT139).
And to add to the mess, some Japanese companies put 'Japan' only on parts made in Japan, and not on parts made in their factories outside Japan...
I bought these from China on eBay. Seller says they are old stock and included old shipping boxes and label pics in the sale listing etc. They were not cheap, as they should not be. When confronted, the seller demands they are not fakes.
They arrived batched and sorted and each was labeled. They test perfectly. They seem good on the weight scale too.
So what do you think? Real or fake?
They arrived batched and sorted and each was labeled. They test perfectly. They seem good on the weight scale too.
So what do you think? Real or fake?
Attachments
A significant deviation on the scale is often a dead giveaway. Part of the picture.
They measured fantastic and they were matched and batched and labeled.
I'm kinda surprised. I always thought it was a good sanity check.
I've had some doozies that were so far off it was outstanding. When you provide all the poor data it helps getting a full refund and not paying shipping fees etc.
You're so connected man, you don't even have to look at eBay China AliExpress.
Schleppers like me, always dabble in the darkness...
🙂
Hold your horses. I have another semiconductor order on route.
I gotta another batch coming out of Jersey, USA and I think we are going find a bad batch of fake junk!
Shipment should be here any day.
I can tell by the correspondence with the seller, it is touch and go.
For example: When I asked the seller about fakes bla bla bla, his response was: "My customers are always happy".
He/she dodges and dances around dialog and is very slow to respond.
More to come...
Today was a small victory. Cheers!
I gotta another batch coming out of Jersey, USA and I think we are going find a bad batch of fake junk!
Shipment should be here any day.
I can tell by the correspondence with the seller, it is touch and go.
For example: When I asked the seller about fakes bla bla bla, his response was: "My customers are always happy".
He/she dodges and dances around dialog and is very slow to respond.
More to come...
Today was a small victory. Cheers!
Most of the mass is in the case and heat spreader (metal tab). So if it is really off, they used Aluminum instead of Copper or Steel. But some legit transistors used aluminum cases (TO-3 for example). The actual die wouldn't be much different compared to the mass of the case.
Interelectrode capacitance is one indicator. Beta or Idss / transconductance measurements help. Breakdown voltage helps. I use a 300 VDC low current current source for most (HP 6186C). Then tests can get more involved, like a curve tracer. But the data sheet indications of package markings is an excellent test. Laser etched cases for old parts is a clear giveaway (=FAKE!). "New manufacture" for old, discontinued devices is another. Brand markings. In the JIS program, a device number is only made by one manufacturer, period. Not like in the US or Europe.
Yeah, dodgy responses from the seller is always a huge warning flag.
For me, I haven't got the time to vet each part, so I buy only from authorized distribution as a rule. Failed parts cost too much in troubleshooting time or taking other parts out with them. Then there is my reputation. Mystery parts are a no-fly option.
Edit: case mass.
Interelectrode capacitance is one indicator. Beta or Idss / transconductance measurements help. Breakdown voltage helps. I use a 300 VDC low current current source for most (HP 6186C). Then tests can get more involved, like a curve tracer. But the data sheet indications of package markings is an excellent test. Laser etched cases for old parts is a clear giveaway (=FAKE!). "New manufacture" for old, discontinued devices is another. Brand markings. In the JIS program, a device number is only made by one manufacturer, period. Not like in the US or Europe.
Yeah, dodgy responses from the seller is always a huge warning flag.
For me, I haven't got the time to vet each part, so I buy only from authorized distribution as a rule. Failed parts cost too much in troubleshooting time or taking other parts out with them. Then there is my reputation. Mystery parts are a no-fly option.
Edit: case mass.
Real
100% original and possibly made in Japan, that solder dipped legs give away 100% made in Japan vibes to me.
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Even toshiba don't always marked made in japan in some packages
Even toshiba don't always marked made in japan in some packages, even though they are 100% made in Japan, that the case for some small packages of transistors, like To-92 and TO-220 and some TO-3P and there are many other cases too, which aren't big enough to mark due to size
Ones made in Japan would be marked as such if there is room, and always marked on factory pack. Anti-stat tubes would be marked, or a bulk pack box. Most Toshiba dies are still made in Japan, and boxes often say “Diffused in Japan, Made in China”. It could only me marked Japan on the package if it was all done there, according to their own documentation. Well, up till a couple months ago anyway there was a very easy way to tell on the Mouser site whose stuff was made in China but the waters are muddied now. On could tell for instance which OnSemi product was made in China by something mentioned on the price page. It surprised me to see just how much of it WAS, even stuff that was typically made in the Korea (Fairchild) plant.
From ebay American seller.
2SA968
Hfe 118 to 146
Ie=6.3mA, Vbe=610mV-ish for all four
V collector to base - Vcc max 5.5VDC of tester, Cob = 108pF-ish for all four
2SC2238
Hfe 150 for all
Ic=1.5mA, Vbe= 586mV-ish for all four
V collector to base - Vcc max 5.5VDC of tester, Cob = 41pf-ish for all four
2SA968
Hfe 118 to 146
Ie=6.3mA, Vbe=610mV-ish for all four
V collector to base - Vcc max 5.5VDC of tester, Cob = 108pF-ish for all four
2SC2238
Hfe 150 for all
Ic=1.5mA, Vbe= 586mV-ish for all four
V collector to base - Vcc max 5.5VDC of tester, Cob = 41pf-ish for all four
