My Transistors, original or copy?

Please give me your opinion (real or fake) for the two TIP35C shown in the pictures on the left. The four other devices (middle and right) were purchased from Mouser (authorized distributor).

The left two are fake, but it is far less obvious than it used to be. They are using the lead free plating, and the leadframe is very close (much closer than other fakes I’ve seen). The quality of the molding and the wrong codes are the only dead giveaways, besides the test results.

You say the ones on the right are from Mouser - must have been a long time ago. They quit making the TO-218 version years ago, and they have the old lead solder plating on the pins. Definitely real, I have some in service that look just like them. And I doubt they ever faked that old version. All the TIPs I’ve ever gotten surplus in that package have been real.
 
Thank you for the reply.


Yes, the TO-218 Morocco version was purchased in 2002 from Mouser. I think those are an older process (Mesa) and the ones from 2020 are planar. The old mesa process might actually be better (performance).


Now I have to go fight the seller that sold me the fakes on Ebay. Sigh. I thought TIP would be much safer than ordering something like 2SC5200 or 2SA1494. And the seller had reasonable rating compared with many others.


I guess all transistors and electrolytics will be ordered from authorized distributors in the future. Fake TIP35C and fake TIP41C is a bit much.


I wonder what is inside all those boxes (assortments/kits) of TO-92 transistors. All fake? All the same die with a dozen different laser marks?
 
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No idea what’s in the “assortments” - I usually buy bulk of any given type (10, 20, 50, 100 or 200) for my “A” stock, depending on how many I expect t to go through over 10 or 20 years. I do keep a lot of “B” stock, most of which is picked up from surplus dealers. I pick up a few, test them, then buy a batch. Pulls, TIPs, vintage Motorola types, germanium, house numbered, etc. There is verily little cross-over. Stuff only goes into “A” stock if it has been verified by test (like batches of 2N3373’s or 15004’s that were too good to pass up, bulk zener diodes, full wave blocks) and some TIP stuff is bought from Mouser (TIP50, which I need A stock of). The B stock isn’t for building any serious equipment with power supply voltages over 80V, and I try not to spend A stock building things that likely will get torn down and recycled. Recycled parts go back into B stock.
 
LU1014D question

Hello.
I have a quick question regarding the unobtanium lu1014d,
I'm in touch with a diy enthusiast who has offered me those transistors,
It is 10 unmatched and 10 matched, five pairs, with curve traces on paper,
He's asking 160 is dollar for all, is it a fair price, I am convinced they are genuine and not pulled
 

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Seems this has been been coming for quite a while, you cannot even use 15 year old trannies and be assured that they are original.:eek:

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24th April 2012, 10:42 AM #5


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Fake Counterfeit 2SB554 and 2SD424 Power Transistors
I am an older experienced service tech. I have an Adcom GFA-555 amplifier that one 2SD424 failed on an amp channel. I won't replace just one device (I believe it will be unbalanced and fail eventually). So, I found the 2SB554 and 2SD424 from an eBay seller in China and ordered a new set of transistors. Guess what? They failed in about a millisecond, no load, no nothin, just the voltage swing killed/shorted 7 of 8 of them. Just want you all to know that now I am replacing those transistors with a new set of ON MJ15024G / MJ15025G. I ordered them from Mouser. THESE must be true NON-COUNTERFEIT parts! Even these transistors are available from China, obvious more counterfeit parts. Just thought I'd throw in my 2 cents worth. Any other ideas out there? Oh yeah, I'm applying for a refund from the China eBay seller.
 
u are better off with Mj21193/94, they are more robust, and better match the 424/552 in gain and sonics. They are constructed of the same perforated emitter tech that the 424 was, it is more robust and reliable given ists 250w rating. Its SOA is also much broader... The amp will survive 2 ohm loads with 8 of these devices. Hopefully they remain in production...
 
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Please take a look at these TIP142T.


The gain is about 4k at Ic = 1 Amp and Vce = 23V. However gain drops to 2.5k at Ic = 1.5 Amp and Vce = 22.5V. [On the one that reached 1.5A before catching on fire.] Base current was applied through a 6.8k resistor and a 1 Ohm current sense resistor was connected in series with the emitter.

One caught fire at just above 1.5A and the other exploded just above 1A before reaching 1.5A. Exploding at 23W does not seem reasonable for a 90W/10A/100V transistor.

The gain should also not be dropping so soon just above 1A so it seems to be acting like a much smaller transistor.

They were clamped (with grease) on a huge copper and aluminum heatsink. Failure was rapid before the heatsink was heated much.
 

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Please look at these marked NJW0281G, C4495 and NJW0302G. Also driver uPC1342V (hard to photograph).

Real or fake?
 

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Quite a conundrum, isn't it? FWIW, when I built my first preamp, it used Jfets J103, and K246. I naively ordered some from "Audio Wind"on Ebay, not knowing about the rampant fakes. Funny though, they have worked flawlessly so far! Guess I got lucky. I've since found originals, for about 8 bucks apiece(!), and I'll keep them if needed. I since ordered some other obsolete trannies from a Canadian supplier on Ebay, only to find they're Chinese! I measured them against my expensive originals, and NONE met the min Hfe, and were beyond 10% out of spec to each other, whilst the originals were virtually spot on!
 
Please look at these marked NJW0281G, C4495 and NJW0302G. Also driver uPC1342V (hard to photograph).

Real or fake?

Here are some more photos after repairs. If anyone has genuine NJW0281G and NJW0302G please post photos of front and back.


Parts physically look nice but I have never purchased these part numbers from authorized distributors so I can not be sure. However one of the NPN's blew at idle (+/- 50V) even before the amplifier could be finally assembled.
 

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SPL28 (29) are inconsistent with any known ON Semi marking scheme. Other than that they are pretty damn good fakes.

Even those TIP142T are convincing fakes, other than the price. Put them in the usual relay driver application and you may have never noticed.

These are parts from AliExpress in the last month. The lead frames on the TIP142T look like the real deal. But electrical testing says otherwise. So when someone says that they only copy expensive parts that is not true. And when someone says that you can tell a genuine part by the copper lead frame (or the lead free finish/lead frame, etc) that is not true either.

The supposed ON Semi parts look very very convincing too. Yet on first turn-on (idle) one shorts. Replace with 2SC5200N/2SA1943A (Toshiba) from Mouser/authorized distributor and guess what... ...the Toshiba transistors work. Sigh.

Instead of putting all their effort into improving the laser marking, copying someone else's logos and the lead frames for the fakes I wish they would put the effort into improving their power transistor die and SOA. I have no problem with a company offering functional quality generics but please stop the faking and the fake logos.
 
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Improving the die actually costs *money*. They can put junker and reject die which cost nothing or next to nothing into “fakes”.

The copper leadframe parts may actually be *real*. Just not the ones that are advertised, and could be rejects. They might try to pass off a TIP31 as something “bigger” and more expensive by marking it as such.