Hi blmn,
The gain ranking is missing. That makes me suspicious (I'm holding a real one in a green case). The lettering should be white, some look silvery - could be the lighting.
Toshiba did change to black cases in later years. Right now, the only ones I would trust as real are ones you know the path from Tosiba and the new On Semi parts that come from an authorized distributor.
What I would do is get access to a good cap meter and check yours out.
-Chris
The gain ranking is missing. That makes me suspicious (I'm holding a real one in a green case). The lettering should be white, some look silvery - could be the lighting.
Toshiba did change to black cases in later years. Right now, the only ones I would trust as real are ones you know the path from Tosiba and the new On Semi parts that come from an authorized distributor.
What I would do is get access to a good cap meter and check yours out.
-Chris
I fixed my capacitance meter today and got the measurements below (130mV bias):
black PNPs: hFE near 70 and cBE near 5.5nF;
green PNP: hFE near 70 and cBE near 2nF;
black NPN: all of them cBE near 1.4nF. Two of them hFE near 40 and the other two hFE near 1.5!!!!.
So, I think just the black pnps are not fakes.
I´ll open the cases to see the dies.
Best regards,
black PNPs: hFE near 70 and cBE near 5.5nF;
green PNP: hFE near 70 and cBE near 2nF;
black NPN: all of them cBE near 1.4nF. Two of them hFE near 40 and the other two hFE near 1.5!!!!.
So, I think just the black pnps are not fakes.
I´ll open the cases to see the dies.
Best regards,
counterfeit
Recently bought two MJ15003 from Fibra-Brandt, they were clearly fake ones. My old H/K citation 19 made an buzzing sound, when trying to power it up after replacing the MJ`s. I have already paid for four new pairs from the same firm. Havent got my order yet, but I guess they are counterfeit also.
What to do next?
Recently bought two MJ15003 from Fibra-Brandt, they were clearly fake ones. My old H/K citation 19 made an buzzing sound, when trying to power it up after replacing the MJ`s. I have already paid for four new pairs from the same firm. Havent got my order yet, but I guess they are counterfeit also.
What to do next?
Continues..
Recevied my second order yesterday, four matcing pairs of MJ1003/4 also two 2N6211, 2N3583. All of the MJ have the marking the wrong way, easily rubbed off, not using any solvents. Inside, the cooling plate is missing! The 2N ones seems to been painted gray on top then marked. Tried contacting Fibra-Brandt, no reply... Will post Pictures later.
OnSemi were also interessted.
Seems my vintage Harman Kardon will have to waith furter to be repaired.
Recevied my second order yesterday, four matcing pairs of MJ1003/4 also two 2N6211, 2N3583. All of the MJ have the marking the wrong way, easily rubbed off, not using any solvents. Inside, the cooling plate is missing! The 2N ones seems to been painted gray on top then marked. Tried contacting Fibra-Brandt, no reply... Will post Pictures later.
OnSemi were also interessted.
Seems my vintage Harman Kardon will have to waith furter to be repaired.
Fake transistors
Lads. and Gents.
Fake transistor or ICs are flown around the market. Even all over the world.
Even I bought from famous dealer, ( Names everybody known ). I still got fakes.
My experience is to check the tr. myself prior to use. How can I test it, simple???
First, prepare a high voltage ps, and a low voltage supply with high current, a low ohm 20W resistor and a voltmeter.
To check a transistor, we check Bvceo, Bvces, Ic, Ie and Ib. These are the major spec. that concern using a tr. is a must.
From the data achieved, and compare to manufacturer's spec. then even if a fake product, it almost fit in most application except for RF, odd case like application consider junction capacitance, leakage at high freq. It's hard to define a true or fake tr. They can make Fake almost like org. Except those low technique ones that even the steel case can easily comes off.
From the photo I seen, most of your tr. are fake, org. tr. steel case not easy come off, unless the base plate were deformed during removing the top hat. This is for sure in org. product. The org. tr. they got a tight spec. on casing, pull test, salt spray test, aging test, in cct. test, burn in test-----etc. After the tr. can passed these tests, the product is rigid and garenteeed.
Usually fake product is hard to get Bvceo, Bvces, and Ic passed, the rest parameter can also be seen!!!
The above info. is my experience on using transistor, and not related to any tr. manufacturer.
WE FIGHT AGAINST FAKES.
Lads. and Gents.
Fake transistor or ICs are flown around the market. Even all over the world.
Even I bought from famous dealer, ( Names everybody known ). I still got fakes.
My experience is to check the tr. myself prior to use. How can I test it, simple???
First, prepare a high voltage ps, and a low voltage supply with high current, a low ohm 20W resistor and a voltmeter.
To check a transistor, we check Bvceo, Bvces, Ic, Ie and Ib. These are the major spec. that concern using a tr. is a must.
From the data achieved, and compare to manufacturer's spec. then even if a fake product, it almost fit in most application except for RF, odd case like application consider junction capacitance, leakage at high freq. It's hard to define a true or fake tr. They can make Fake almost like org. Except those low technique ones that even the steel case can easily comes off.
From the photo I seen, most of your tr. are fake, org. tr. steel case not easy come off, unless the base plate were deformed during removing the top hat. This is for sure in org. product. The org. tr. they got a tight spec. on casing, pull test, salt spray test, aging test, in cct. test, burn in test-----etc. After the tr. can passed these tests, the product is rigid and garenteeed.
Usually fake product is hard to get Bvceo, Bvces, and Ic passed, the rest parameter can also be seen!!!
The above info. is my experience on using transistor, and not related to any tr. manufacturer.
WE FIGHT AGAINST FAKES.
Hi mitwrong,
One notorious vendor had to close shop (thank goodness!!).
If I have to pay more per piece to get good ones, fine. That's cheaper than the alternative by far.
-Chris
Yes, that's my point about being careful where you buy ........
Also true. Here, the major suppliers buy direct from the manufacturer. If I get fakes they will make sure the rest of the stock is isolated and the supply chain is investigated. This helps everyone who wants real parts. Also, I get replacement parts. These days I do not worry about getting real On Semi parts. Japanese semiconductors are a problem for me where they weren't in the past. I do, however know where to buy to get fakes most of the time. Avoid.
One notorious vendor had to close shop (thank goodness!!).If I have to pay more per piece to get good ones, fine. That's cheaper than the alternative by far.
-Chris
Fake transistors
Dear Members:
I think nowadays, tr. manufacturers are seldom make metal case transistors. instead, they make tr. with plastic packages, or even they start to make large production on FET's.
Therefore, the fake production are raise up and begin their products. the only way for myself to get parts is taken out from old equipment. No reason to buy parts from market. Every time I have to test the part prior before use. Although these parts were old, not nice looking, rust, scratched ---- . I still prefer to use these stuff instead of new ones. Even I paid full price, I still get fake tr. on new ones.
WE FIGHT AGAINST FAKES
Dear Members:
I think nowadays, tr. manufacturers are seldom make metal case transistors. instead, they make tr. with plastic packages, or even they start to make large production on FET's.
Therefore, the fake production are raise up and begin their products. the only way for myself to get parts is taken out from old equipment. No reason to buy parts from market. Every time I have to test the part prior before use. Although these parts were old, not nice looking, rust, scratched ---- . I still prefer to use these stuff instead of new ones. Even I paid full price, I still get fake tr. on new ones.
WE FIGHT AGAINST FAKES
anatech said:Hi Alex,
The only proper way to test SOA is using the same fixture as the manufacturer. Consult the On Semi data books as they will often include the circuit. They are all different.
That's why we've been looking at junction capacitance and DC beta.
-Chris
Can you please point me to specific pdf datasheet where i can find this circuit because it's not included in the ones i have:
MJL4281A-MJL4302A.pdf
MJL3281A-MJL1302A.pdf
MJE15028-29-30-31.pdf
I also did a search at the On semi web site but i can't find it.
Thank you
Alex
Hi Alex,
In the old days, they were included in the data book, also at the end under application notes. Of course we are talking about Motorola.
This is an article describing breakdown modes for power transistors from the On Semi site. I am sure there are others hiding around town.
-Chris
In the old days, they were included in the data book, also at the end under application notes. Of course we are talking about Motorola.
This is an article describing breakdown modes for power transistors from the On Semi site. I am sure there are others hiding around town.
-Chris
I don't think you'll have a problem with MOSPEC parts. They'e generic , but not counterfeit.
A counterfeiter would use the original logo of the original manufacturer, like OnSemi or Toshiba, etc.
MOSPEC is a generic manufacturer of parts that have come out of patent, and they make parts that perform to spec. You just don't pay for the brand name.
A counterfeiter would use the original logo of the original manufacturer, like OnSemi or Toshiba, etc.
MOSPEC is a generic manufacturer of parts that have come out of patent, and they make parts that perform to spec. You just don't pay for the brand name.
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