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Old 21st December 2003, 06:50 PM   #1
trwh is offline trwh  United Kingdom
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Default Help with possible counterfeit 2SC3281/2SA1302

Hi

I would be very interested in anyone's opinion as to whether these transistors are counterfeits or not. The 1302 is the device on the right, and the 3281 is on the left.

Click the image to open in full size.

Many thanks for your help,
Tim
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Old 21st December 2003, 07:47 PM   #2
sam9 is offline sam9  United States
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Probably. It hardly seems likely that Toshiba would use a messy splotch of silicon adhesive in that manner.
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Old 22nd December 2003, 04:17 AM   #3
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The silicone looks odd to me too, although I only have experience with other Toshiba models, not those particular parts.

However, the die size looks to be about right, from what I remember when I took apart some OnSemi, Toshiba, and Sanken transistors a while back. As far as I can remember, the counterfeits had a smaller die than the ones shown in your pictures - closer to what a 2n3055 would be like.

Those look a little smaller than my OnSemi MJ15003 and MJ21194 that I have lying open at the moment, but that's to be expected as the Toshiba's a lower dissipation part.

If they are fakes, they aren't as bad as some of the ones lying around. I know Rod Elliott has mentioned that he's had some that had dice that were 3mm on a side - smaller than what you have, for sure.
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Old 22nd December 2003, 08:02 AM   #4
trwh is offline trwh  United Kingdom
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Thanks for your replies. The dice on my devices are about 3mm square. I just found the following pic of a genuine device:

Click the image to open in full size.

Heh, no contest!

I shall try and get some written confirmation that these are fakes from Toshiba, and then I'll get on to RS components who sold me the devices.

Has anyone had any experience of getting refunds for counterfeit devices before? I'm concerned that I shall have a lot of explaining to do! Also, do you think I can claim for all the 'collateral' damage caused - i.e. to driver transistors, etc.

Thanks,
Tim.
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Old 22nd December 2003, 02:10 PM   #5
trwh is offline trwh  United Kingdom
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A conclusion here:

http://www.instantboard.com/users/ro...hp?p=2447#2447

Hope this helps,
Tim
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Old 22nd December 2003, 04:13 PM   #6
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Default Here's a suggestion:

Buy from a franchised distributor. They buy from the factory. Guys like MCM buy theirs from parts brokers, who buy from anyone. The broker just buys what they can, when they can, from whomever they can. And if that guy is selling fakes.........you get the picture.

Jocko
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Old 22nd December 2003, 05:41 PM   #7
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Default Second Sourcing Can Suck...........

Yeah, I know it only too well.
My local parts supplier provided a 2SC5200 with PMC brand name.
I asked for Sanken and after a look in the stores the reply was that was all they had.
This transistor was needed for a PA amp that was needed for a show that night.
When I got back to the shop I fitted this new transistor and did a static run up and allowed ample time (30 mins) for thermal stability/bias adjustment and all was ok.
The customer (a friend) rang during this time and I said that the amp looked like a goer.
As soon as I hung up I went to the amp and applied low level audio and all was ok.
I then turned the level up and on the first clip that transistor went S/C.
Guess who had to phone back real quick and say the amp would not be ready for that night.............!!! .

Eric/ - Now insists on originals.
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