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How to identify fake JFETs?
How to identify fake JFETs?
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Old 10th June 2019, 12:06 PM   #31
EUVL is offline EUVL  Europe
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> 'Stormsonic' in post 19 showed that measurements of fake units can actually be pretty close to genuine ones.

How does he know they are fake ?
Has he other meassurements such as noise, capacitance, ..... to prove so ?


Signing off,
Patrick
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Old 11th June 2019, 02:40 PM   #32
davidsrsb is offline davidsrsb  Malaysia
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It is perfectly normal with the big manufacturers for the same die to be packaged and tested at several plants (often third party), often using different leadframes and moldings.
They are all genuine parts.
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Old 11th June 2019, 05:37 PM   #33
ej25awd is online now ej25awd  Canada
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Quote:
Originally Posted by davidsrsb View Post
It is perfectly normal with the big manufacturers for the same die to be packaged and tested at several plants (often third party), often using different leadframes and moldings.
They are all genuine parts.
Not perfectly normal for the Toshiba 2SK170 which is the original body of this thread.

Give us your documentation that support Toshiba 2SK170 dies are assembled by a third party who intentionally use a smaller epoxy package from what was specified on the 2SK170 datasheet.
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Old 12th June 2019, 01:20 AM   #34
davidsrsb is offline davidsrsb  Malaysia
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Has Toshiba told you that they only use one package style?
I don't believe that in the posts above that Marantz would have bought fakes and the HDAM module would not work with the typical die used by the fakers.
There are few third party test and package plants here in Malaysia, all producing finished parts for some of the semiconductor majors in a totally official and legit way. I am sure that there are others around SE Asia.
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Old 12th June 2019, 01:53 AM   #35
tsmith1315 is offline tsmith1315  United States
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While I 100% believe the Marantz parts are genuine, it's been pretty well documented through measurements that many of the discontinued Toshiba jfets offered now are not genuine.
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Old 12th June 2019, 03:21 AM   #36
ej25awd is online now ej25awd  Canada
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Quote:
Originally Posted by davidsrsb View Post
Has Toshiba told you that they only use one package style?
I don't believe that in the posts above that Marantz would have bought fakes and the HDAM module would not work with the typical die used by the fakers.
There are few third party test and package plants here in Malaysia, all producing finished parts for some of the semiconductor majors in a totally official and legit way. I am sure that there are others around SE Asia.
davidsrb,

Give me a Toshiba 2SK170 datasheet/ECN/ECO that supports your pure speculation of the existence of another 2SK170 TO-92 packaging dimensions that matches the OP's counterfeit 2SK170 measured dimensions. If you don't
have any just STOP!

You should be aware that reckless and unfounded statements just add more confusion to members which could end up as potential preys for counterfeiters.
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Old 12th June 2019, 09:08 AM   #37
davidsrsb is offline davidsrsb  Malaysia
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Quote:
Originally Posted by tsmith1315 View Post
While I 100% believe the Marantz parts are genuine, it's been pretty well documented through measurements that many of the discontinued Toshiba jfets offered now are not genuine.
That almost everything for sale now on auction sites is fake we are sure of, they don't even measure close
Even the Linear Systems LSK170 is being faked
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Old 12th June 2019, 09:21 AM   #38
kamis is offline kamis  Serbia
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Show me an original Toshiba J-Fet ( measured) which has no 2mm center line on the top.
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Old 12th June 2019, 09:29 AM   #39
andyr is offline andyr  Australia
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So now that genuine thru-hole 2SK170s are no longer available - can anyone tell me the code for the SM equivalent?

Or the SM equivalent of the 2SK369?

Thanks,
Andy
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Old 12th June 2019, 10:42 AM   #40
fredbloggstwo is offline fredbloggstwo  United Kingdom
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Hi there,

if you are going to test a lot of transistors for fakes or otherwise, can I suggest you get yourself a Peak DCA 75 tester.

As well as testing the obvious parameters, it will plot the characteristics on a computer screen, which you can then chack directly against the manufactures' data sheet as a first level of confidence.

Brilliant investment for about 100.

Regards

Mike
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