My Transistors, original or copy?

[mbrennwa]

I'll believe you they are legitimate. I am surprised though.

So was I. Curve tracing clearly shows these parts are the real deal, though.

 

[anatech]

Very interesting indeed!

 

[wg_ski]

I have just tried to rub lettering with high percentage alcohol and lettering stays as before - not a tiny bit was removed nor ink faded. Lettering is exactly the same after 'cleaning' with tissue with alcohol on it.

I would not like to try with some other chemicals, like acetone (nail polish remover) or anything else. I hope that alcohol test is enough for testing lettering ink.

The other tests you did were enough to convince me they’re real.

 

[wg_ski]

They aren’t that widely available to begin with. Not everybody carried them but they were designed into a lot of high end and PA stuff. They were the slightly lower power/current high speed 20 MHz DRIVER set specifically for the MJ15024/5 family. So were the MJ15026/7 - a direct 24 MHz version of the MJ15024/5 with the same SOA - which were NEVER available through distribution but there was a data sheet.

I knew I’d find that data sheet if I just quit looking for it….. The 250 watt version of the 020/021.

 

[chiily]

But, https://www.diyaudio.com/community/threads/my-transistors-original-or-copy.82638/post-6687435

And those ones I posted earlier are the genuine article. Received as free samples from Onsemi

 

[thimios]

LM317 fake for sure.
Out voltage whatever,even no load .
Connecting any load voltage is zero.
I have to replace all regulators.
It seems that i paid for pcb only ..

 

[NanoFarad]

Looks like so.

 

[Zung]

I reported a similar case with the LM337.
I think somebody got a big batch of rejects and sell them as new. It appears both Ali & eBay are aware: they immediately issue refunds, no question asked.

 

[NanoFarad]

These are not rejects, even their appearance doesn't match genuine LM317/37.

 

[anatech]

So I have to say, why risk buying from sources outside authorized distribution channels?

Total failures are easy. The real headaches come from parts that work, but not well.

 

[thimios]

Real LM317 received from Mouser today.
"Total failures are easy. The real headaches come from parts that work, but not well."
Agree,two of fake boards are functional but burned immediately when output shorted.
On the left is the original,on the right is the fake.

 

[anatech]

Then there is regulation and noise. That can cause whatever they are powering to operate poorly compared to the performance they should give.

 

[NanoFarad]

Here electronic component buisness is little weird compared to other part of the globe (I assume so). 4-5 yrs ago i bought genuine 317/337(ST & ONSEMI 'dual & single gauge') from an authorised dealer at a very down to earth price, whereas then the price was tenfold+ at big online vendors like RS & Mouser. I believe this is applicable only for industry grade parts, not any exotic type which is barely available here at local distributors. Anyway, then i found some NATIONAL made LM337T. The strange thing is their physical dimensions is identical to datasheet drawing except the marking which i found little different then the original NATSEMI marking of LM337T. I believe these are early genaration Natsemi adjustable regulators, relabeled & sold.

 

[anatech]

STMicroelectronics if those are genuine. They would be fine.

 

[xenofonn]

Good afternoon from Greece!
Today arrived from ebay us seller quantity of IRF820A mosfets
It is ok or not?
It is genuine VISHAY?

 

[anatech]

Hi xenofonn,
Cosmetics are getting better on fakes. Look up the data sheet and check to make certain the markings agree. Measurements would be the next check.

If they were listed as new manufacture on a discontinued part - they are fake. If the price was below what it should be .... probably fake. It just isn't worth buying stuff you can't be sure of.

 

[Julian RO]

It is genuine VISHAY?

FAKE!!!

 

[NareshBrd]

I agree, the finish and feel are way off.
You risk damaging the circuit, they are that bad.
Try and return them.

 

[xenofonn]

OK ! Thank you all !

 

[jitter]

I would still try to make some measurements as anatech suggested. The problem with a visual inspection is that we may be condemning a slightly off genuine batch as fake and a well made fake as genuine while in reality, things are reversed.
However, having said that, I would suspect anything from non-authorized resellers (think Avnet, Digikey and the likes) as fake unitil proven otherwise.