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Old 7th March 2007, 10:12 PM   #71
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In response to my notification of possible fakes, I got some more free ones, unfortunately, all fakes as well. This was back then. Just now, I sent them a message asking for the 2SA872, and reiterating the high possibility of fake 2SA1233's. They are friendly folk there, and are as much a victim as I am. They might be able to complain to their suppliers.
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Old 7th March 2007, 10:17 PM   #72
sbrook is offline sbrook  Canada
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May I offer this Panasonic datasheet as evidence of the preformed legs and standoff?

http://www.ortodoxism.ro/datasheets/...JC00011BED.pdf
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Old 7th March 2007, 10:32 PM   #73
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Is Panasonic (Matsushita) the only manufacturer of those transistors? What about the 2SA872? If they look like my 2SA1233's (without the stand-offs and offsets), can I assume it's fake?
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Old 7th March 2007, 10:53 PM   #74
sbrook is offline sbrook  Canada
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Well, the 2SA872 are manufactured by Hitachi (now Renasas)

http://www.ortodoxism.ro/datasheets/...r/mXyzyuuu.pdf

The data sheet only shows stand offs ... not offsets.

Chris (anatech) is correct for some manufacturers - the lead formation is done later, but I think for these it is a part of the manufacture process, just as Philips (Mullard) did with their LokFit transistors (BC147/148/149 etc.) They were designed for automatic insertion.

While we can never be sure, it sure sounds like the ones you got were definitely of questionable origin and I would be suspicious of the new type if they don't look like those on the data sheet. Also, check the printing on the labelling ... if it looks like the ones that you got last, be very suspicious and check them out for HFE and polarity before installing.
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Old 7th March 2007, 11:26 PM   #75
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Quote:
Also, check the printing on the labelling ... if it looks like the ones that you got last, be very suspicious and check them out for HFE and polarity before installing.
What aspect about the labeling would be suspicious?

And even the polarity can be wrong? Perhaps that's why I initially thought they were NPN transistors, because that's what the multimeter said...
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Old 7th March 2007, 11:40 PM   #76
sbrook is offline sbrook  Canada
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Well, for example, there is no apparent manufacturer marking (although I gather this isn't uncommon with the 2S series.)

But what I mean is the physical printing characteristics ... the font, the placement on the case etc.
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Old 8th March 2007, 12:47 AM   #77
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Hi,
For Japanese transistors, only one manufacturer makes a number. Another device from someone else is assigned a different number, even if they are identical parts.

Hi sbrook,
In all my years of servicing, I've received transistors with bent legs depending on whether they were delivered on tape or bulk. I've never once noticed any brand in particular and don't even think about it. taped transistors are almost always bent for Japanese parts.

Panasonic (Matsushita) may be different. I can't say.

-Chris
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Old 8th March 2007, 12:55 AM   #78
sbrook is offline sbrook  Canada
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Quote:
Originally posted by anatech
[B]Hi,
For Japanese transistors, only one manufacturer makes a number. Another device from someone else is assigned a different number, even if they are identical parts.
Which sure makes it difficult when the manufacturer doesn't actually display how he marks up his transistors! One of the good things about most Euro/N.Am. mfrs ... they actually show their typical markings so you can get a better grip on what you're looking at!

It also makes it difficult to find replacements. Goodness knows it's hard enough when you HAVE got multiple manufacturers manufacturing to similar specs.

Quote:
In all my years of servicing, I've received transistors with bent legs depending on whether they were delivered on tape or bulk. I've never once noticed any brand in particular and don't even think about it. taped transistors are almost always bent for Japanese parts.
I believe you ... though it still adds "?" marks as to the authenticity of the devices.
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Old 8th March 2007, 02:15 AM   #79
anatech is offline anatech  Canada
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Hi sbrook,
Quote:
I believe you ... though it still adds "?" marks as to the authenticity of the devices.
The failure rate alone does that, and measured specs. Japanese manufacturing is to a very high standard.

Quote:
It also makes it difficult to find replacements.
Not really. Get the Japanese spec books and look them up. There will be a few popular devices in use that will be close. You can even "google" them.

-Chris
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Old 12th April 2007, 11:10 PM   #80
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Hello there people.. i have been doing much reading of this forum recently and learned much from you all. in particular i have been reading up on these counterfeit transistors....

pictured are 2 5200s and 2 1943s... for each, 1 genuine, and 1 presumed counterfeit.

my question is only this.. The ones with the clear markings in the smooth rectangle have been mentioned many times here and elsewhere on the web, but does anyone know for certain if Toshiba have ever manufactured transistors in this exact packaging?

if someone with more knowledge and experience than me could clarify this once and for all, it would be helpful to many people to have such an obvious difference clearly acknowleged.

apologies for the quality of the photo.. i really did try to get a good clear one.. but photography is not a skill i have.

greets...

steve.
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