There is another way to those possible Dave Kirby quotes.....remember silicon foundry lines run lots of wafers through the fab line at one time these are tested automatically and inked at the end of the process and put inro store. The wafer are drawn and cut and encapsulated (sometime halfway round the world from the fab line) when required. It being possible that high yeilding wafers are drawn first. It is possible low yeilding wafers my be returned to the silicon refiner to use as material for a new batch of rods (boule). These may be intercepted or bought by a small company for whom it is worthwhile to bond up chip from low yield wafers. On the other hand they could wash off the ink (testfail marker) and bond up the lot making money out of known duds that look genuine if opened (difficult with plastic encapsulation, without damaging the chip metallisation) I have bought old 3inch wafer in the past on eBay to use as lecture samples. They had a genuine looking device on them but no id.

Alan
G3NYK

----- Original Message ----- From: "Alexander Pummer" <[email protected]> To: "Discussion of precise time and frequency measurement" <[email protected]>
Sent: Monday, October 10, 2016 6:28 PM
Subject: Re: [time-nuts] Prologix USB-GPIB Controller


Once upon the time I designed some power-supplies, used parts from a sound name US company, they asked for $12.-- each --it was long time ego -- the equipment supposed to built in Asia, the manager -- I was one outside consultant -- told me that we can not use that expensive parts, my Chinese colleague told, that I should not worry that part will not cost more than a dollar, at the end we got the parts for 57 cents in Hong Kong, the manager was on the opinion that the cheap parts are counterfeit, therefore we opened one expensive original and one cheap one; the silicon was identical, as the performance too....was it a perfect copy, or one original?, who cares it worked like the original, but much cheaper.

73
KL6UHN
Alex

On 10/10/2016 10:13 AM, Dr. David Kirkby (Kirkby Microwave Ltd) wrote:
On 10 October 2016 at 09:35, Charles Steinmetz <[email protected]>
wrote:

Poul-Henning wrote:

And for voltage references, "pre-owned" is likely to mean "better".
Perhaps, but third-world recyclers are not known for gentle treatment
during the parts removal process.

I had some cheap ($10) GPS receiver boards shipped to me in a plastic
kitchen bag from yikunhk on eBay. 4 boards in the same bag, all scratching
each other. The bag was not anti-static.

There are all number of possible explanations of why boards can be made so
cheaply, when the ICs appear to cost more than the boards.

* The chips are counterfeit
* The chips are similar to what they are supposed to be, but have been
relabeled.
* They are made at the same factory as the real devices, on what I've heard described as the "ghost shift", where they are not officially made, but are
the same devices.
* They are recycled.
* They are stolen.

It is anyone's guess once you start buying semiconductor devices from eBay.
Maybe you are lucky, maybe you are not.

You dramatically increase the probability a part is good if sourced from a
reputable source (e.g. RS or Farnell in the UK). That is not to say that
the parts are not counterfeits, as even the best suppliers can get caught,
but they are more likely to be ok.

I recently bought a supposedly original Samsung battery for my Samsung
Galazy S3 phone from a local shop. The phone had all sorts of issues with
this battery, so I concluded it was a poor counterfeit.  I thought I'd be
safe buying directory from Amazon (not a 3rd party), but on reading reviews on Amazon, I was not convinced those were genuine Samsung batteries either,
so I did not buy from Amazon.

Eventually I bought a battery from the Samsung website. The phone now works ok. I don't know if Samsung actually make the batteries themselves, but I
think I have a better chance of buying from the Samsung website than from
anywhere else.

I've had "Duracell" batteries leak. At one time I used to blame Duracell,
but now it has cross my mind whether they might have been bought on eBay
and were counterfeits. I can't recall where they were purchased, but now I
will only purchase batteries from sources I consider reputable.

Dave.
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