[time-nuts] Prologix USB-GPIB Controller

Alan Melia alan.melia at btinternet.com
Mon Oct 10 18:42:15 EDT 2016

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.


----- Original Message ----- 
From: "Alexander Pummer" <alexpcs at ieee.org>
To: "Discussion of precise time and frequency measurement" 
<time-nuts at febo.com>
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
> Alex
> On 10/10/2016 10:13 AM, Dr. David Kirkby (Kirkby Microwave Ltd) wrote:
>> On 10 October 2016 at 09:35, Charles Steinmetz <csteinmetz at yandex.com>
>> 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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