counterfeit output transistors

spacelord · Dec 1, 2005

Hello,

I am working on bringing a sansui 9090 back from the dead. I was looking through my special stash of unobtanium output transistors, trying to find 4 2sc1116a's.

I remembered a post from echowars where he said that these transistors are regularly counterfeited.

When looking at my 4 replacement sankens, two are clearly different looking than the other two.

I bought these years ago, and didn't know there were knock off's being sold

How can I tell the bogus ones from the good.

I don't want to install a knock off, blow the driver board, and then I'm back where I started

Please advise

Chris

spacelord · Dec 1, 2005

more info

Here are a couple of pics.

The output on the left is the one that is suspect.

Maybe echo will have some words of wisdom on how to tell the difference between the good and the bad

Chris

glen65 · Dec 1, 2005

You can use On Semi. MJ21194

Here's some good info addressing counterfeit semis.
http://sound.westhost.com/counterfeit.htm

Stene · Dec 1, 2005

Genuine

spacelord said:
How can I tell the bogus ones from the good.

Please advise

Chris

This is the genuine Sanken 2SC1116A

EchoWars · Dec 1, 2005

spacelord said:
Here are a couple of pics.

The output on the left is the one that is suspect.

Maybe echo will have some words of wisdom on how to tell the difference between the good and the bad

Chris

The one on the left is a fake (the one with the circle on the underside of the case).

spacelord · Dec 1, 2005

EchoWars said:
The one on the left is a fake (the one with the circle on the underside of the case).

Echo--

Thanks for letting me down easy !!! :tears:

I guess the good news is that out of 8 that I purchased only two are junk, and I did not install them (glad I asked first)

Oh well live and learn--

Chris

EchoWars · Dec 1, 2005

You also notice that the fakes are smooth and shiny, wheras the original Sanken's have a kind of 'matte' finish.

I had a quite large pile of fakes here at one time. Whatever you think you got taken for, I can guarantee it was small potatoes compared to the drubbing I took. :tears:

Stene · Dec 2, 2005

Counterfeit

Conspicuous is the shape

EchoWars · Dec 2, 2005

Yeah...I meant to mention that too... Only holds true for the Sanken's though, since a lot of other brands use a rounded case.

merrylander · Dec 2, 2005

One thing I have noticed in fake Toshibas is that the fakes have a thick copper base, much like real Sankens, but genuine Toshibas are always on the thinner steel base. And you would be surprised at the otherwise relieable dealers who seem to ship out fakes. Simplest way is to go with On Semi.

Rob

seadzz · Dec 2, 2005

Does anyone have photos of genuine 2SA747 transistors? I picked up some not long ago but do not have anything to judge them against. I bought them as part of a batch of 2SC1116A transistors. Thank God I did not buy a box load.

I'll post a pix of what I bought later on today

Many thanks.

sdz

Edit:

Judging by what has been posted by others it seems I may have also been had. Bought these from one of the vendors that gets some praise on these boards.

Bogus or Real???? Looks like my 747's are possible but the 1116's are questionable.

Guess I will be sticking with the MJ Series from OnSemi

Stene · Dec 2, 2005

Sanken 2SA747A

seadzz said:
Does anyone have photos of genuine 2SA747 transistors?

Here it is.

LBPete · Dec 2, 2005

Here is an original 2SA747 taken from an 8080DB and a 2SA747 I got recently from Mat Electronics. You can see the difference in case contour. The original one has a flat top and sharp rolls to the edges. The top of the “bogus” one is kind of bulbous.

What is interesting is that an outfit like Mats sells these things. You would think an established company like that would know their suppliers and buy from reputable sources. The only saving grace that the bogus ones have is they are dirt cheap, less than $2 a copy. I plan to use them as sacrificial lambs if I don’t now the history or background of a driver board.

- Pete

EchoWars · Dec 2, 2005

LBPete said:
Here is an original 2SA747 taken from an 8080DB and a 2SA747 I got recently from Mat Electronics.
- Pete

You know better than that...I'm surprised.

Distributors and retailers don't care. It's a case of CYA for the tech, and to that end I buy only On-Semi's, or from Woodang or Amplabs.

LBPete · Dec 2, 2005

Yes, I know better but for $1.23 each, I thought I'd take a chance on a pair. I wouln't use them in any serious gear, just for testing.

- Pete

spacelord · Dec 2, 2005

LBPete said:
Yes, I know better but for $1.23 each, I thought I'd take a chance on a pair. I wouln't use them in any serious gear, just for testing.

- Pete

What exactly would they do, if placed into a functional unit???

Speaking of woodang, I just ordered half a dozen Sanken 2SC1116a's

Enough to fix this 9090 of mine, and to replace my marantz 2325 spares (the two bogus ones)

Chris

EchoWars · Dec 3, 2005

spacelord said:
What exactly would they do, if placed into a functional unit???

Blow up. And take shit with them as they shed this mortal coil.

Speaking of woodang, I just ordered half a dozen Sanken 2SC1116a's

Enough to fix this 9090 of mine, and to replace my marantz 2325 spares (the two bogus ones)

You didn't happen to order any spares? I need one single 2SC1116A...

spacelord · Dec 3, 2005

EchoWars said:
Blow up. And take shit with them as they shed this mortal coil. You didn't happen to order any spares? I need one single 2SC1116A...

Glenn, (it is Glenn isn't it??)

I ordered 4 for the Sansui,

And then I had a spare set of 2sa747's and 2sc1116a for my 2325 Marantz.

I was going to use my Marantz spares to fix the sansui, when I discovered the two fakes.

So, no I don't have any extra's.

One of the 2sc1116a's that came out of the sansui tested VERY slightly out of the tolerances (not shorted) that cdfixer provided to me. (testing them with my Fluke DMM with the diode test position).

If you think it would be of use to you, you can have it.

Chris

EchoWars · Dec 3, 2005

What did you see that makes you think there's something wrong with it?

LBPete · Dec 4, 2005

EW, If a used one will do, drop me a PM with your address and I'll send you one.

- Pete

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