Hi all,
After a few output failures recently, I decided to open some of the culprits. MJ15022/3, the size of the die is 2mm x 2mm and the wires connecting the die to the base and emmitor are as thin as hair! For comparison I opened an old 2N4399, die size 5mm x5mm and the connecting wire is a lot thicker and quite stiff.
Am I correct in assuming that the others are fake? What do I do, go back to my supplier and *****?
After a few output failures recently, I decided to open some of the culprits. MJ15022/3, the size of the die is 2mm x 2mm and the wires connecting the die to the base and emmitor are as thin as hair! For comparison I opened an old 2N4399, die size 5mm x5mm and the connecting wire is a lot thicker and quite stiff.
Am I correct in assuming that the others are fake? What do I do, go back to my supplier and *****?
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Hi
You are looking at the inside of the transistor with the top taken off, the dark part is the actual die of the transistor, and I coloured them in to show the size.
The two are next to each other and at the same scale so those out there who have opened a TO3 before can compare the size of the die with what they know as to be the "correct" size.
I am trying to get confirmation from others that the MJ transistor is a fake, as this is the first time I have ever opened one up.
Any comments?
You are looking at the inside of the transistor with the top taken off, the dark part is the actual die of the transistor, and I coloured them in to show the size.
The two are next to each other and at the same scale so those out there who have opened a TO3 before can compare the size of the die with what they know as to be the "correct" size.
I am trying to get confirmation from others that the MJ transistor is a fake, as this is the first time I have ever opened one up.
Any comments?
Top Removal
I actually reomoved three, the one MJ shown the top actually just popped off on mounting on the heatsink, hence the clean removal. The others I clamped the top in a vice, squeezed it a bit, then clamped the body in the vice and whacked the top off with a old screwdriver. Not to much effort but I was a bit angry!
The all had some white "gunk" over the die, feels like silicon sealer, and unless you clean it off you cant see the die or its size. The wires were embedded in this and they were really thin, like one strand of a copper strand wire.
I am convinced I have been ripped off twice now, cause of the three MJ150xx I checked were bought from different supplies at least a year apart. Problem is now I dont know whats good and whats not, I have a small drawer full of MJ15oxx's bought at different times and from different suppliers. They probably got them from the same distributer.
Any simple way of testing them without putting them in a amp? At least if they blow then they wont mess the rest of the amp.
DieterD
I actually reomoved three, the one MJ shown the top actually just popped off on mounting on the heatsink, hence the clean removal. The others I clamped the top in a vice, squeezed it a bit, then clamped the body in the vice and whacked the top off with a old screwdriver. Not to much effort but I was a bit angry!
The all had some white "gunk" over the die, feels like silicon sealer, and unless you clean it off you cant see the die or its size. The wires were embedded in this and they were really thin, like one strand of a copper strand wire.
I am convinced I have been ripped off twice now, cause of the three MJ150xx I checked were bought from different supplies at least a year apart. Problem is now I dont know whats good and whats not, I have a small drawer full of MJ15oxx's bought at different times and from different suppliers. They probably got them from the same distributer.
Any simple way of testing them without putting them in a amp? At least if they blow then they wont mess the rest of the amp.
DieterD
Have a look at Rod Elliots list of fakes around
http://www.sound.westhost.com/counterfeit.htm
the MJ15003/4 fakes have been around for a while & there's a lot of detail regarding the differences listed on Rod's site
Cheers
Paul
ps whats the weather like at the moment, my mom said the drought seems to be breaking up in Jo'burg
http://www.sound.westhost.com/counterfeit.htm
the MJ15003/4 fakes have been around for a while & there's a lot of detail regarding the differences listed on Rod's site
Cheers
Paul
ps whats the weather like at the moment, my mom said the drought seems to be breaking up in Jo'burg
I tried to get the tops of some real Motorolas and only managed with one out of three. Your technique must be better than mine. 
I would open up my real 15022s and see how big the die is, but they are a little busy right now (being kept company by Jimi Hendrix).
I would open up my real 15022s and see how big the die is, but they are a little busy right now (being kept company by Jimi Hendrix).
It's ****ed down for the last few days and it looks like the rain is about to start today. Too late for the food crops I fear, but at least the cattle guys will be happy.
I bought some mj15003/04 from arrow electronics some time ago and after a few kicked the can I decided to pop the cover and have a look and to my surprise they were fakes. I contacted them and was told they are all from Onsemi but these don't look like Onsemi's.
Does anyone have a source they know for sure aren't selling fakes or is just a crap shoot?
Has anyone seen the nsc model in the picture and does that nsc mean National semiconductor?
Does anyone have a source they know for sure aren't selling fakes or is just a crap shoot?
Has anyone seen the nsc model in the picture and does that nsc mean National semiconductor?
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According to the following link
http://www.elektronikforum.de/ic-id/#N
which Netlist supplied in another recent thread, NS has three
logos, but none of them fits even remotely.
On the other hand, I decided to look up NSC in chipdirs manufacturer
list
http://www.xs4all.nl/~ganswijk/chipdir/c/n.htm
and there is an entry for NSC saying "see NS", where NS is, of
course, Natinoal Semiconductor!!!
Puzzling indeed. Maybe plain text isn't considered a logo and
is sometimes used instead of a logo?
http://www.elektronikforum.de/ic-id/#N
which Netlist supplied in another recent thread, NS has three
logos, but none of them fits even remotely.
On the other hand, I decided to look up NSC in chipdirs manufacturer
list
http://www.xs4all.nl/~ganswijk/chipdir/c/n.htm
and there is an entry for NSC saying "see NS", where NS is, of
course, Natinoal Semiconductor!!!
Puzzling indeed. Maybe plain text isn't considered a logo and
is sometimes used instead of a logo?
The logo on the right device has clearly the intention to be the National Semiconductor logo. It's definitely NOT Onsemi.Easyamp said:
To the best of my knowledge NSC doesn't make the MJ15003/4 and according to my books, only Motorola which is now Onsemi and RCA are producing them.
The left transistor on the picture seems to carry the 'bat' label from Motorola. If this is correct, it looks like you have an old fake Motorola device.
I took apart a MJ15025 and provide a picture of a Onsemi MJ15024 stamp for reference.
They are not fakes and I can assure you that taking off the cover was a tough job.
One thing is sad here: The fact that Arrow electronics says they come from Onsemi is a lie or plain lack of knowledge.
I hope they do know they sold you fakes. If they don’t, the door is open for many producers of fake devices at Arrow. Not good for a company who claims to be “…a leading provider of services to the electronics industry.”
/Hugo
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