could you do me a favor, and list for each of those two devices the following:
all of the printing on the case
the codes in the dimples on the plastic (as well as which dimple each one is in)
as well as the same for any other sets of known good and known fake transistors you have. i'm putting together a counterfeit identification guide, and i have a theory that the numbers in the dimples have some form of date coding, and the date coding should match somehow with the printed date code.
all of the printing on the case
the codes in the dimples on the plastic (as well as which dimple each one is in)
as well as the same for any other sets of known good and known fake transistors you have. i'm putting together a counterfeit identification guide, and i have a theory that the numbers in the dimples have some form of date coding, and the date coding should match somehow with the printed date code.
The Funny thing is I made a Video in the process of doing this
My technique only shows me using a hammer and gently whacking them directly on the seam 
The epoxy shattered and soon split, and I pulled the two halves apart. 
One thing that was obviouse about the green fake was that there was no "O" or "R" and as someone else said the screw whole was smaller, and the numbers just did not look remotely similar to the others.
I would split one of the black ones open but I left the bag of fakes at my uncles house, and won't be able to get them back till next week
I am glad now to have made a video to resort to, because I announce the exact numbers of the green fake; 7L in place of what would be 5H/5I and the number below that was 0109 I sound horrible in the video but it makes for good reference.
I also have some other Toshiba's I need more info on, doubt they are fakes but they are obsolete. These being 4x 2SC793, from an old audio amplifier I think, in TO-3 packages.
Hello everyone! I need a couple of 2sa1301/2sc3280 transistors. I have found a pair on e-bay. Can you please tell me if they are originals?
Here is the link:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=320404666221
Thanks in advance,
Andy.
Here is the link:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=320404666221
Thanks in advance,
Andy.
If they came from Europe or N. America, I'd be a bit suspicious. But since they are coming from Hong Kong, you can be assured they are fake. HK is the Asian central distribution point for all things fake.
I'd like to take everyone on a Chinese 'fakes tour' over there. Including the markets and factories. It's a breathtaking and sad experience.
Buy some 2SC5200/A1943 devices (or the Fairchild eqv., can't remember their #) from Digikey. Guaranteed real.
..Todd
I'd like to take everyone on a Chinese 'fakes tour' over there. Including the markets and factories. It's a breathtaking and sad experience.
Buy some 2SC5200/A1943 devices (or the Fairchild eqv., can't remember their #) from Digikey. Guaranteed real.
..Todd
EWorkshop1708 said:
If you compare the applicable part of the Safe Area curve (for higher power applications at least), and adjust for a realistic Tc, you'll find the usable power dissipation isn't that different. The max dissipation rating is completely useless in the real world unless you immerse your output stage in liquid nitrogen and run low voltage rails
In general, I second giving up on trying to find genuine but long obsolete higher Ft devices and use the 5200/1943 or the On Semi devices. For any sane audio use their Ft is plenty high. A faster part is often *not* better better for audio. And if you're using it for RF purposes, use an RF transistor. This is diyAudio not diyRF...
andy_barosanu said:
Yep! These ones on eBay seems as real FAKE as they can be. The cheaper lighter green color on PNP package and only partially visible words are a giveaway they are FAKEs. And then, "Japan" underneath is just to assure you they are not made there.
Coming from HK? I wouldn't used them in the circuit even if it's FREE.
Obsolete parts? Just use newer devices with lower fT when possible. I learned my lessons with 2SA1095. 6 out of 6 2SA1095 has C-E shorted during 2 hours and my third time to pull things apart to fix the darn output stages.
If I ever have to replace the genuine Toshiba pairs I am using in one of my amplifiers.... I cirtianly would not purchase replacements from ebay, too much fake junk is sold there in general as it is.
So just go with the good advice and purchase newer high power transistors, and for strange packages like the 2SD845/2SB755, there are NTE92/93, and they are higher rated and I have never heard of NTE devices being faked!
Of course, that is if you can afford them....
So just go with the good advice and purchase newer high power transistors, and for strange packages like the 2SD845/2SB755, there are NTE92/93, and they are higher rated and I have never heard of NTE devices being faked!
Of course, that is if you can afford them....
CrazzyAbtTubes said:there are NTE92/93, and they are higher rated and I have never heard of NTE devices being faked!
Of course, that is if you can afford them....
Yeah - why would anyone fake a fake? NTEs are fake to begin with. Well, maybe the NTE123 and 130 are real.... but anything high performance or out of print? Forgetaboutit.
Back at the end of August, I bought some 2SA1302 & 2SC3281 transistors from ebay seller lpcsunny2008. I didn't know about this counterfeit thing at the time. Now that they have arrived, I cracked 2 of them open. They look like fakes to me.
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