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'[EE]:: Why not to overclock an AVR'
2011\10\31@150507 by RussellMc

face picon face
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See image.
Seemed like one way to get message across :-)

Stack Exchange answer. Text format wrecks layout.

__________________

How to make life more interesting 101:

If you don't care

that your results may sometimes be wrong,
that your system may sometimes crash,
that your life may be more interesting,
that your Segway clone only occasionally does face-plants for no obvious reason,
that ...

then by all means run the part outside manufacturer's spec

You get what you don't pay for.
If you have a $10 head, buy a $10 helmet.

It may often work.
It may not work sometimes.
It may not be obvious that it isn't working sometimes.

A divide may usually work
A jump may usually arrive.
A table may belooked up correctly.
An ADC value may be correct.

Or not.


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2011\10\31@160727 by Carey Fisher

face picon face
On Mon, Oct 31, 2011 at 3:04 PM, RussellMc <spam_OUTapptechnzTakeThisOuTspamgmail.com> wrote:

> See image.
>

Related:

Media today carrying "news" that "bogus/fake/reworked/defective" chips from
the far east are getting into USA military equipment endangering troops,
etc.  Not surprising but disappointing.  What are the legions of government
QA inspectors that stop production at the tiniest (sometimes imagined)
infraction doing?

Carey Fisher
Chief Technical Officer
New Communications Solutions, LLC
678-999-3956
.....careyfisherKILLspamspam@spam@ncsradio.co

2011\10\31@162233 by RussellMc

face picon face
Carey said:

> Media today carrying "news" that "bogus/fake/reworked/defective" chips from
> the far east are getting into USA military equipment endangering troops,
> etc.  Not surprising but disappointing.  What are the legions of government
> QA inspectors that stop production at the tiniest (sometimes imagined)
> infraction doing?
>
> Carey Fisher


The number 1 rule I've learned from doing things in "the Far East".

         You have to be there!

You MUST have a competent nominee "on the ground" who has your and
only your interests at heart and who is authorised to act on your
behalf.

With respect to ICs this means at a minimum that you need traceability
up a supply chain OR deal with people out of country who take this
rule seriously. eg if you buy from Digikey you expect them to be
serious enough that they have buyers in country who do random factory
visits and inspections and who know what they are looking for.

And even at that level it only just might work as there is enough
indirection and wriggle room.

If you were eg getting people to make volume quantities of products
for you and ship them directly to a customer you need at very very
very least a competent inspection service you can trust or, really,
your woman/man on site. Anything less than this produces certain
results.(The nominee can be a national of the country concerned - but
they MUST be YOUR person in heart and mind.)



           Russell McMahon


'[EE]:: Why not to overclock an AVR'
2011\11\01@045756 by Electron
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face

I buy PICs from Microsoft Direct only.

For other chips, if in volume, I try to obtain them from the manufacturer too.

Other stuff (capacitors, etc..) can fail too.. and it's harder to source them
directly from the manufacturer. It tend to order from Mouser, Digikey, Farnell
(Newark) and/or RS-Components only. Sometimes Distrelec. End of sourcers..

I guess we must do the best we can do, but then there's a limit after which
hope is our only weapon..

Anyhow this story about fake IC's is disturbing, money is the king of our era
and some sellers would gladly sell their mother for 1$, go figure if they care
about our circuits. Or, they do only to the extent they won't lose a customer,
etc.. but if they're hidden and unknown, we'll lose even this deterrent.




At 21.21 2011.10.31, you wrote:
{Quote hidden}

>

2011\11\01@060018 by RussellMc

face picon face
> I guess we must do the best we can do, but then there's a limit after which
> hope is our only weapon..

> Anyhow this story about fake IC's is disturbing, money is the king of our era
> and some sellers would gladly sell their mother for 1$, go figure if they care
> about our circuits. Or, they do only to the extent they won't lose a customer,
> etc.. but if they're hidden and unknown, we'll lose even this deterrent.

There are limits to what can be check on, but they aren't always pushed.
I would assume that military contractors had stringent incoming
inspection tests and acceptance criteria to meet.

Some fakes are excessively good, but common sense will spot a moderate
% of fakes.
I have seen 105C labelled caps that could be seen to be fake just by
holding in the hand.

Good resistors usually cluster so tightly around their nominal values
that there are significant gaps in the distributions between values.
That's essentially saying that eg +/- 5% resistors are actually
typically better than +/-5%.

Batteries can be exquisitely labelled (I have some faked "Sony" cells
that appear perfect copies)(sold in NZ by a "reputable" reseller) but
those who fake them usually scrimp on the chemical content as well as
stealing their market and weight is usually an excellent test. Top
Nimh AA should be 28 gram + . Some are 30-31 gram. Some are about 20
gram :-)

I have also seen NimH cells which are too heavy on a number of
occasions. I think these are batches of cells from a prior or bulk job
with higher capacities which are down labelled to meet our mAh spec.
I'm happy with that as long as it's always one way. I have batteries
at the moment from two manufacturers but allegedly from one supplier
(one of China's big 3.) The batteries from the normally more trustable
manufacturer do not match those from the usually less reliable
manufacturer and I have enough paperwork and context to be  reasonably
sure that the batteries from the usually worse supplier are in fact
genuine. SO this means that the others are from another source (almost
certainly). These are not necessarily clones or fakes or necessarily
low performance - just not from an approved source. That said, from
the small sample I have one is slightly over nominal mAh spec and the
other somewhat under. Under is never allowed and never happens so far
when genuine.

A nice "win" some years ago was to take plain unlabelled boxes of NimH
AA batteries from a storeroom and show the Chinese factory engineers
that by doing a simple graph of battery mad distributions you could
show that  there were two batches of batteries involved and that
something had changed. On set of boxes was double peaked in
distribution with high and low peaks of certain % and mass while other
was single peaked with *AFAIR) a suspicious cutoff tail. 50 cells per
box AFAIR.

Easier is just weighing whole boxes of cells and finding per box mass
variations. Very naughty when it's that obvious.

For other components good production testing or selected testing will
catch many  variants. Not always viable for domestic equipment but
you'd expect it for military gear.

I recall from some years ago hearing of some cloned Motorola (AFAICR)
) parts - some sort of power device - in a TO220 or similar from dim
memory. They worked but would fail very early in action. Harder to
spot. A possibility that they may have been rejects from a testing
process which got back into the market. There things like leakage,
capacitances, quiescent currents etc may give a lead to something
being wrong when primary parameters were hard to test.

I have seen out of spec samples put aside and then subsequently reused.

I have sought to track down a missing faulty item for testing and
after a while hav e been handled an item whose hand labelling was "not
quite" the same as the rest of the rejects. My not being able to speak
Chinese was a positive factor for somebody on that occasion.  (That
manufacturer no longer used - but it COULD happen many places.)

I have been taken to a Chinese factory in a consultancy role and then
realised subsequently that I was being sold to the manufacturer as a
customer's representative. (That was by a US national who was well
steeped in Chinese market matters). (Long not involved with).





         Russell McMaho

2011\11\01@061620 by V G

picon face
Microsoft?

On 2011-11-01, at 4:57 AM, Electron <electron2k4spamKILLspaminfinito.it> wrote:

> I buy PICs from Microsoft Direct only

2011\11\01@104249 by RussellMc

face picon face
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2011\11\01@135110 by Joe Wronski

flavicon
face
On 10/31/2011 4:06 PM, Carey Fisher wrote:
>   On Mon, Oct 31, 2011 at 3:04 PM, RussellMc<.....apptechnzKILLspamspam.....gmail.com>  wrote:
>
>> See image.
>>
> Related:
>
> Media today carrying "news" that "bogus/fake/reworked/defective" chips from
> the far east are getting into USA military equipment endangering troops,
> etc.  Not surprising but disappointing.  What are the legions of government
> QA inspectors that stop production at the tiniest (sometimes imagined)
> infraction doing?
>
> Carey Fisher
> Chief Technical Officer
> New Communications Solutions, LLC
> 678-999-3956
> EraseMEcareyfisherspam_OUTspamTakeThisOuTncsradio.com
I worked at a place that supplied parts to the government, and it had a time machine.  48 hour burn-in was accomplished in less than 24.  Maybe they could call it 48 hr if they pushed voltage and temperature?
Joe

2011\11\01@143220 by RussellMc

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part 1 1215 bytes content-type:text/plain; charset="iso-8859-1" (decoded quoted-printable)

> I recall from some years ago hearing of some cloned Motorola (AFAICR)
> ) parts - some sort of power device - in a TO220 or similar from dim
> memory. They worked but would fail very early in action. Harder to
> spot. A possibility that they may have been rejects from a testing
> process which got back into the market. There things like leakage,
> capacitances, quiescent currents etc may give a lead to something
> being wrong when primary parameters were hard to test.

This is they - not rejects - "genuine" fakes made by people who know
what they are doing but don't care to do it right.

 http://sound.westhost.com/fake/counterfeit-p1.htm

MJ15003
MJ15004

This page start in 2000 and is still going strong in 2008 !!!

A range of different versions of the fake. Must be a very attractive part.

2 x small die in parallel.
One small die, big copper heat spreader.
One larger die bu no copper spreader.
Parts that change between sample and bulk supply but are identical externally.
Pars sold via reputable and long trusted Asian distributors.
....

Good pictures
RIOT reduced jpg attached of some photos.


   Russell McMahon


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2011\11\01@172104 by William \Chops\ Westfield

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On Nov 1, 2011, at 2:59 AM, RussellMc wrote:

> I would assume that military contractors had stringent incoming
> inspection tests and acceptance criteria to meet.

Maybe.  Sometimes that may get pushed onto the supplier.  You order  your 5400 "mil spec" logic chips from whereever, and assume that a  good part of the necessary testing has been done by the manufacturer  (I don't know; there seems to be less of a "mil spec part" market than  there used to be.  Perhaps it wasn't keeping up with technology very  well.  There was supposedly an incident where the required testing  procedures for some advanced semiconductor (DRAM chip?) resulted in  LOWER end reliability than COTS parts (apparently burn-in at max temp  and max voltage wasn't such a good idea?))


> I have seen 105C labelled caps that could be seen to be fake just by
> holding in the hand.

How?  I don't think I've seen enough 105 vs 85C caps next to each  other to notice any difference, other than labeling...

BillW

2011\11\01@175617 by RussellMc

face picon face
> > I have seen 105C labelled caps that could be seen to be fake just by
> > holding in the hand.
>
> How?  I don't think I've seen enough 105 vs 85C caps next to each
> other to notice any difference, other than labeling...

These more or less failed the "right to live" test.
Any sorry specimen that looks/feels like that is not a quality cap,
let alone a top spec one.
Didn't stop the manufacturer using them without comment though.

R

2011\11\01@200356 by Electron

flavicon
face

Argh.. I meant Microchip, what a bad typo. <OT>Actually I dislike Microsoft and its products as much as I like Microchip and its products. :D</OT>


At 11.16 2011.11.01, you wrote:
>Microsoft?
>
>On 2011-11-01, at 4:57 AM, Electron <electron2k4spamspam_OUTinfinito.it> wrote:
>
>> I buy PICs from Microsoft Direct only.
>

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