My Transistors, original or copy?

[pdul]

It would be damn nice with some kind of factory outlet for Japanese transistors so we could rule the fakes out all together

[pliedtka]

To Wojtek,
Wojciech, they're OK, I think - real TOSHIBA'S, mine looked just like yours. I also bought some MJE15030/31, 340,350 SC5200/SA1943, etc. The place in Toronto area is called Global Electronics Supplies Inc. and to me they sell the real stuff.

[rubli]

Dear fellows.

I analized some sanken transistors that I bought in different places , and besides that the "suspects" ones have a low beta, I discovered something that i would like to confirm .

I have attached two photos, I marked with a red circle the zone of interest. one has a number engraved inside this small circular recess, and the other is blank.

the one with date code 78P is definitely a fake.

Could this be considered a "rule" for detecting malicious sanken's ?

any comentarie will be appreciated

regards

Alexander rubli
alex@rubli.net

[unclejed613]

if it had been the TO-3P packages, i would have better data for you on the dimples in the plastic. however, the second picture shows a dimple with rounded edges, as if the case had been stripped with a wire wheel or sandpaper, so that device is suspect. the dimple in the first picture has sharp edges.

[rubli]

thanx, where could I see more info on the dimples ?

thanx

[tinitus]

If theres a "6" or "9" there could be a difference

On the fakes I have seen shown here especially the number 6 and 9 are more rounded, which they are not on originals

Also it seems the small dot holes you have marked should be sharp edged and smooth almost shiny at their bottom

And all letters/numbers are nicely rounded at all ends

Mind you, Im no expert, I just happen to have some old burned ones

[unclejed613]

info about the mold marks (dimples) can only be compiled if you have access to a lot of known good parts over a span of about 5 or 10 years. manufacturers do NOT publish any info on mold marks. one very good reason that mold mark data isn't published would be to keep counterfeiters guessing, but i suspect the real reason it's not published is that it's too much information to keep track of. i was lucky to find a correctly laid out drawing and description of the lot/date code/ beta range ID markings for sanken devices. toshiba keeps more accurate data on their marking layouts, and publishes the data in their "Reliability Program Guide", because their company has an active program to monitor the reliability of the devices they manufacture (and discover counterfeits as a side benefit).

[tiefbassuebertr]

In this case also this thread could be of interest:
bipolar (bjt) transistor families for audio power output stages

[unclejed613]

the company i work for has decided to hire a testing facility that specializes in counterfeit detection. there are a lot of methods the facility uses to detect counterfeits.
1. X-ray machines to look inside the device without having to break it apart, and even look at the emitter pattern of the die.
2. transistor curve tracers which can even identify what transistor used to make a fake might have been originally
3. accurate dimensional measurements including the flatness of the heat sink tab.
4 capacitance measurements (this is currently one of the methods i use)
5. mold marks and printing (also one of the methods i currently use.
6 materials testing. are the fakes made with different materials than the original?

the biggest part of solving the problem has been to identify the sources of the fakes, bypass the processes that allow these sources to provide certain components and order the devices directly from the manufacturer of the equipment. so far, so good, but there's a steep learning curve for management, because nobody in the company has ever identified this problem before, and nobody wants to admit that an 800lb gorilla is regularly getting poked in the eye.

[glen65]

Originally Posted by unclejed613

the company i work for has decided to hire a testing facility that specializes in counterfeit detection. there are a lot of methods the facility uses to detect counterfeits.
1. X-ray machines to look inside the device without having to break it apart, and even look at the emitter pattern of the die.
2. transistor curve tracers which can even identify what transistor used to make a fake might have been originally
3. accurate dimensional measurements including the flatness of the heat sink tab.
4 capacitance measurements (this is currently one of the methods i use)
5. mold marks and printing (also one of the methods i currently use.
6 materials testing. are the fakes made with different materials than the original?

the biggest part of solving the problem has been to identify the sources of the fakes, bypass the processes that allow these sources to provide certain components and order the devices directly from the manufacturer of the equipment. so far, so good, but there's a steep learning curve for management, because nobody in the company has ever identified this problem before, and nobody wants to admit that an 800lb gorilla is regularly getting poked in the eye.

What kind of meter are you using to do the capacitance measurements?