Bad year to be buying semiconductors

Thread Starter

DickCappels

Joined Aug 21, 2008
7,984
I bought some 2N3904's from a new vendor because my old reliable vendor ran out in May and doesn't expect to get any more until October - of NEXT YEAR(!).

It was amazing that this new vendor could sell them for2¢ (U.S.), half the price from my old reliable vendor, and being mainly a supplier to hobbyists how did the get almost 400,000 of them when my distributor goes without any for over a year?

It gets more suspicious. These are supposed to be Fairchild but they don't avlanche like the Fairchild part and ONSemi parts. The vendor told me that is because they came from an ONSemi fab. Ok, but what about the date code: "331" which means they were produced in the 31st work week of a year ending with a "3". They are too new and shiny to be from 2013, its not 2023 yet...then I spotted a lot of ads on an Asian storefront like Amazon. To wit:
1634313043610.png

There were over a dozen vendors on that site with this same photo some offering these Chinese-made transistors for 1¢ (U.S.) each. They are made in China and I suspect counterfeit. So, if you find your shiny new bargain-basement 2N3904's don't quite work the way you expect, it is probably because they are not really 2N3904.
 

MrChips

Joined Oct 2, 2009
24,625
I can imagine that if you are manufacturing "fake" components you could produce 100 million generic transistors and label them with whatever part number is in demand at the moment. Who would notice the difference?
 

olphart

Joined Sep 22, 2012
99
The shortages being addressed by counterfeit products?!! Just when I thought it was bad enough !!
I wonder how many products will be compromised by this?
I have 3 micro controller based products that are on hold - no chips Anywhere until April+.
 

dl324

Joined Mar 30, 2015
13,534
They are too new and shiny to be from 2013, its not 2023 yet...then I spotted a lot of ads on an Asian storefront like Amazon
Shiny leads are a dead giveaway that they're relabeled. You're lucky they even work.

The sellers of these things are clueless. I've seen close-up pictures on eBay with enough detail to tell that they're counterfeit.

I'm good to go with 2N3904. I went to a swap meet and got a bag of 500 for free, along with some LM3914 (in JDR electronics packaging as I recall) actually LM3909 in NTE packaging...
 
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Hamlet

Joined Jun 10, 2015
472
I've been segregating parts by when and where I obtained them. I always keep a few of the old ones as standards against newer/questionable parts. I noticed that any chip, mosfets in particular, that have a date code of "B9PO"
is fake.
 
Something similar happened to me with the MMBT3904, which is the SMT version of the 2N3904. Inventory all but disappeared from Digikey.
Fortunately Mouser does have inventory.
It appears that some vendors like STMicro or Onsemi are no longer producing them.

In their place, there are companies like NextGen or Panjit.
 

Hamlet

Joined Jun 10, 2015
472
I've been using https://lcsc.com/ for awhile now. Shipping isn't too bad, and parts are cheap, but not unbelievable.
Everything comes in anti-static bags or tubes. They are out of onsemi 2N3904 , but 3 chicom venders show thousands, and LGE has been good to me in the past, and they have 1500pieces. If you want MMBT3904, they have hundredes of thous., between dozens of Taiwan/Chichom venders.
 
I use opto isolators that need 1500V isolation and can handle 800V movement in 4 to 6nS. Most isolators can not with stand sharp edges in the voltage. There are multiple venders that make pin compatible parts which are slow. I think the slow parts would be relabeled with the fast numbers and some one would make $90 each. When life started "going to hell" I saw in some places the price jumped from $4.00 to $100.00. No parts no work. Very simple. I ordered more than a year of parts out of my pocket. (I know there are the right parts.)
I also have bought back any product not in use. I retrieved all old down revision boards and removed parts as I need them.
I also redesign for what parts I can get. Not easy.
Probably I am crazy to invest a month or two wages in a inventory. But I still have a job and am shipping product.
 
Probably I am crazy to invest a month or two wages in a inventory. But I still have a job and am shipping product.
No, you're not crazy. That's a bold & smart move. I'd throw down a months wages on cocktails if it served to lubricate the right contacts.

I my prior posts I appear somewhat glib, sorry. I'm afraid there's more surprises ahead. We're living the chinese curse, “May thou live in interesting times.
 

Thread Starter

DickCappels

Joined Aug 21, 2008
7,984
Something that was in volume production in the early 1970's can't be so hard to make using 2020 technology. (I feel a cold wind coming down from BC).

I just would not bother with an LM741 these days, though I recent bought several through a good distributor just in case an actual need for one turns up. Maybe like a "Hey, this amplifier has too much bandwidth and not enough noise - what can I do about?" type problem.
 

ApacheKid

Joined Jan 12, 2015
435
I bought some 2N3904's from a new vendor because my old reliable vendor ran out in May and doesn't expect to get any more until October - of NEXT YEAR(!).

It was amazing that this new vendor could sell them for2¢ (U.S.), half the price from my old reliable vendor, and being mainly a supplier to hobbyists how did the get almost 400,000 of them when my distributor goes without any for over a year?

It gets more suspicious. These are supposed to be Fairchild but they don't avlanche like the Fairchild part and ONSemi parts. The vendor told me that is because they came from an ONSemi fab. Ok, but what about the date code: "331" which means they were produced in the 31st work week of a year ending with a "3". They are too new and shiny to be from 2013, its not 2023 yet...then I spotted a lot of ads on an Asian storefront like Amazon. To wit:
View attachment 250367

There were over a dozen vendors on that site with this same photo some offering these Chinese-made transistors for 1¢ (U.S.) each. They are made in China and I suspect counterfeit. So, if you find your shiny new bargain-basement 2N3904's don't quite work the way you expect, it is probably because they are not really 2N3904.
It would be interesting to get a known good example of one of these and the methodically compare them, carefully and diligently subject them to some basic set of tests that expose some difference, surely their characteristics will differ?
 

dl324

Joined Mar 30, 2015
13,534
I just would not bother with an LM741 these days, though I recent bought several through a good distributor just in case an actual need for one turns up.
I have a number of pieces of Tektronix gear that use the 741, so I have dozens on hand in case I need one for a repair. They used it wherever they didn't need something better. I had some stock from the late 70's, #12 gave me about a dozen pulls that he had no use for, and I recently bought some from someone who was selling parts he got from the estate of a longtime Tektronix employee.

It seems that they still use LM741 in schools. It has limitations that newer designs don't have, though it was a great design in its heyday, and requires students to learn more about how opamps actually work.
 
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