D
DaveC
Guest
Just max voltage, I think...? 60v vs. 100v
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Spehro Pefhany
Guest
On Thu, 11 Dec 2008 09:41:59 -0500, the renowned "Michael A. Terrell"
<mike.terrell@earthlink.net> wrote:
Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
<mike.terrell@earthlink.net> wrote:
Done: <3tn3k4l4liui531b6pu2781et5u242at6k@4ax.com>Spehro Pefhany wrote:
On Thu, 11 Dec 2008 02:12:00 -0800, the renowned PhattyMo
phattymo@not.net> wrote:
Phil Allison wrote:
"DaveC"
I need to buy some '3055's. Is there much risk of getting a counterfeit? I
read that because these are so cheap, they are being substituted (and
relabelled) for more expensive transistors. But there's not much profit in
counterfeiting 3055's.
Should I be concerned?
** Well, I have bought counterfeit BC639s for 30c each - they were very
likely reject BC547s relabelled.
The aim of the counterfeiter is sell devices he can get for almost nothing
that near impossible to sell and make a killing by falsely re-labelling
them.
2N3055s are still very popular and so easy to sell - but lots of other
old, oddball TO3 types are not.
Expect fakes to be offered on eBay and elsewhere.
..... Phil
'They' are faking everything now. There have been incidents of caps
being faked too.
I have a bag of 1,000 fake Panasonic trimpots.
Can you post a picture of them, and the real Panasonic pots on
news:alt.binaries.schematics.electronic
Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
M
Michael A. Terrell
Guest
Spehro Pefhany wrote:
A little fuzzy, but thanks. BTW, you can get better images of small
parts on a flatbed scanner, but you have to lay a white cloth or thick
sheet of paper over it. Its possible that they are old stock, and
someone played with the adjustments to make sure they all turned before
selling them. I've seen some of that style where the plastic degrades
from the wrong lubricant, and they fell apart when you tried to turn
them. The plastic was soft and sticky, under the knob.
--
http://improve-usenet.org/index.html
aioe.org, Goggle Groups, and Web TV users must request to be white
listed, or I will not see your messages.
If you have broadband, your ISP may have a NNTP news server included in
your account: http://www.usenettools.net/ISP.htm
There are two kinds of people on this earth:
The crazy, and the insane.
The first sign of insanity is denying that you're crazy.
On Thu, 11 Dec 2008 09:41:59 -0500, the renowned "Michael A. Terrell"
mike.terrell@earthlink.net> wrote:
Can you post a picture of them, and the real Panasonic pots on
news:alt.binaries.schematics.electronic
Done: <3tn3k4l4liui531b6pu2781et5u242at6k@4ax.com
A little fuzzy, but thanks. BTW, you can get better images of small
parts on a flatbed scanner, but you have to lay a white cloth or thick
sheet of paper over it. Its possible that they are old stock, and
someone played with the adjustments to make sure they all turned before
selling them. I've seen some of that style where the plastic degrades
from the wrong lubricant, and they fell apart when you tried to turn
them. The plastic was soft and sticky, under the knob.
--
http://improve-usenet.org/index.html
aioe.org, Goggle Groups, and Web TV users must request to be white
listed, or I will not see your messages.
If you have broadband, your ISP may have a NNTP news server included in
your account: http://www.usenettools.net/ISP.htm
There are two kinds of people on this earth:
The crazy, and the insane.
The first sign of insanity is denying that you're crazy.
H
Hugh Gibbons
Guest
In article <0001HW.C565FBB50004E91CB01AD9AF@news.sf.sbcglobal.net>,
DaveC <me@bogusdomain.net> wrote:
Since 2n3055 is still in production (from ON Semiconductor) you should
be safe buying it from a reputable distributor.
That reminds me of a couple of gray-market horror stories. I had
specified a 18pF, 2%, C0G capacitor for use in a radio circuit. We made
these radios at a rate of about 1000 a week. Naturally, we ran out of
caps and naturally, the buyer had failed to plan sufficient lead time to
replace them. So he crossed his fingers and ordered a couple reels of
caps from a gray market supplier.
A day after they put them on the line, I was greeted by technicians who
wanted me to help figure out what was wrong with the circuit I designed.
It was these caps. Some of them were around 18 pF. They were mixed
values and some were mechanically unstable. Very ugly. I figure they
were floor scrapings from rubber dog crap factory. But somebody had
taken the trouble to put 3000 or 10000 of them on a reel, make a
realistic looking Murata label and sell them for a few bucks on the gray
market.
More recently, I inherited a project that had been designed several
years ago. So it included some unobtainium parts, in particular a
SHC605. That's an obsolete sample-and-hold circuit. Recently, we had a
new build of these boards and most of them didn't work. So we isolated
the problem down to this part, measured its ins and outs and concluded
it didn't work at all. Then I cut one open and found out it didn't even
have a die inside. Almost all of them we had left were like that.
Between the boards these went on and the labor involved, this cost us
several thousand dollars.
Companies should hire hit men to go after these counterfeiters. It'd be
cheaper than accepting their bad parts into our processes.
But anyway, 2N3055 is still in production, so you're in luck.
DaveC <me@bogusdomain.net> wrote:
Any gray market part is a risk, especially if it's out of production.I need to buy some '3055's. Is there much risk of getting a counterfeit? I
read that because these are so cheap, they are being substituted (and
relabeled) for more expensive transistors. But there's not much profit in
counterfeiting 3055's.
Should I be concerned?
Thanks,
Since 2n3055 is still in production (from ON Semiconductor) you should
be safe buying it from a reputable distributor.
That reminds me of a couple of gray-market horror stories. I had
specified a 18pF, 2%, C0G capacitor for use in a radio circuit. We made
these radios at a rate of about 1000 a week. Naturally, we ran out of
caps and naturally, the buyer had failed to plan sufficient lead time to
replace them. So he crossed his fingers and ordered a couple reels of
caps from a gray market supplier.
A day after they put them on the line, I was greeted by technicians who
wanted me to help figure out what was wrong with the circuit I designed.
It was these caps. Some of them were around 18 pF. They were mixed
values and some were mechanically unstable. Very ugly. I figure they
were floor scrapings from rubber dog crap factory. But somebody had
taken the trouble to put 3000 or 10000 of them on a reel, make a
realistic looking Murata label and sell them for a few bucks on the gray
market.
More recently, I inherited a project that had been designed several
years ago. So it included some unobtainium parts, in particular a
SHC605. That's an obsolete sample-and-hold circuit. Recently, we had a
new build of these boards and most of them didn't work. So we isolated
the problem down to this part, measured its ins and outs and concluded
it didn't work at all. Then I cut one open and found out it didn't even
have a die inside. Almost all of them we had left were like that.
Between the boards these went on and the labor involved, this cost us
several thousand dollars.
Companies should hire hit men to go after these counterfeiters. It'd be
cheaper than accepting their bad parts into our processes.
But anyway, 2N3055 is still in production, so you're in luck.
S
Spehro Pefhany
Guest
On Thu, 11 Dec 2008 23:13:26 -0500, the renowned "Michael A. Terrell"
<mike.terrell@earthlink.net> wrote:
sorry, not much depth of field either because the lens was wide open.
The parts are 6mm wide.
outside of the factory.
Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
<mike.terrell@earthlink.net> wrote:
Yeah, it was done with an okay camera, but hand-held & no flash,Spehro Pefhany wrote:
On Thu, 11 Dec 2008 09:41:59 -0500, the renowned "Michael A. Terrell"
mike.terrell@earthlink.net> wrote:
Can you post a picture of them, and the real Panasonic pots on
news:alt.binaries.schematics.electronic
Done: <3tn3k4l4liui531b6pu2781et5u242at6k@4ax.com
A little fuzzy, but thanks. BTW, you can get better images of small
parts on a flatbed scanner, but you have to lay a white cloth or thick
sheet of paper over it.
sorry, not much depth of field either because the lens was wide open.
The parts are 6mm wide.
Sealed packaging (with printed logo) so nobody played with themIts possible that they are old stock, and
someone played with the adjustments to make sure they all turned before
selling them. I've seen some of that style where the plastic degrades
from the wrong lubricant, and they fell apart when you tried to turn
them. The plastic was soft and sticky, under the knob.
outside of the factory.
Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
P
Phil Allison
Guest
"Hugh Gibbons"
** Wrong.
The risk is HIGHEST if the part IS in production and is popular with
repair techs and /or hobbyists.
See this page for a few examples:
http://sound.westhost.com/counterfeit.htm
....... Phil
Any gray market part is a risk, especially if it's out of production.
** Wrong.
The risk is HIGHEST if the part IS in production and is popular with
repair techs and /or hobbyists.
See this page for a few examples:
http://sound.westhost.com/counterfeit.htm
....... Phil
E
Eeyore
Guest
DaveC wrote:
'Hometaxial' (single diffused) process yielded a durable (large SOA)
design with 800kHz fT, Motorola's epitaxial was less durable but had an
fT of ~ 2.5MHz.
A similar problem existed with the 2N3442. It could cause amplifiers to
be unstable if the wrong 'variety' was sourced. A notorious cause of
problems with kit amplifiers back in the mid 70s.
"Summary:The 2N3055 power transistor was introduced by the Radio
Corporation of America (RCA) in the early 1960s. It was one of the first
silicon power transistors, offered unrivalled second breakdown immunity
and found many applications particularly in audio power amplifiers and
linear power supplies. Other companies tried to copy it with varying
degrees of success: one company acknowledges it now by naming a power
MOSFET after it. We trace its history, manufacture and eventual decline
against pressure from competing technologies. Modern simulation tools
have been used to investigate the operation of the device which
illustrate its good, and not so good, features. We also relate its
geometry to a SPICE model. Neither of these tools would have been
available to the original developers. We propose that this transistor be
given a place in the archives of history, ranked alongside other famous
devices of the 20th century such as the 300B tube."
http://ieeexplore.ieee.org/Xplore/login.jsp?url=/iel5/16/20748/00960371.pdf?arnumber=960371
"You can build good amps with 2N3055/MJ2955's and they are pretty cheap.
I've built a <.01% amp @50W using them which sounds great.
Many people think these are past their sell-by date, but I think that
they are still OK as a starter.
The old hometaxial RCA 2N3055 was slow (800kHz) and had a large gain
variation (non-linearity) ranging between (say) 120 at 100 mA and 30 at
4A. This was a problem in many 1970's amps which did not have enough
gain to linearise the outputs with feedback. For example if your open
loop gain is 2000 and closed loop 30, as defined by the feedback ratio,
the actual gain will be around 29.6. But if the open loop gain changed
to 8000 the closed loop gain becomes 29.92. That represents a distortion
level of 1%. No wonder many amps sounded different. You can't get these
RCA devices anymore, but ST and ON Semi still sell 2N3055/MJ2955's.
So you need a high open loop gain, and you should get good performance.
You can use Miller compensation if you are careful about the input stage
(see tcpip's forum), but JLH's method seems to be better.
The latest 2N3055 from ON Semi is similar, I suspect, to their MJ15003/4
processing. The SOA of the 2N3055 is up to 40V at 115W, and 60V at about
1A which is higher than any previous epitaxial 2N3055. And, they'll
usually be fine up to +/- 38V power supplies for 60W amps, better than
the SOA I have seen for TIP3055/TIP2955.
They have an fT around 2.5 MHz which is similar to MJ15003/4."
http://www.diyaudio.com/forums/showthread/t-93633.html
bottom of page
Incidentally, the Vcer figure of 70V is most appropriate to the majority
of applications.
Graham
I've never seen a 100V Vceo 2N3055. No, it's speed. RCA's originalBeware of the difference between the 2N3055 and 2N3055H.
Graham
Just max voltage, I think...? 60v vs. 100v
'Hometaxial' (single diffused) process yielded a durable (large SOA)
design with 800kHz fT, Motorola's epitaxial was less durable but had an
fT of ~ 2.5MHz.
A similar problem existed with the 2N3442. It could cause amplifiers to
be unstable if the wrong 'variety' was sourced. A notorious cause of
problems with kit amplifiers back in the mid 70s.
"Summary:The 2N3055 power transistor was introduced by the Radio
Corporation of America (RCA) in the early 1960s. It was one of the first
silicon power transistors, offered unrivalled second breakdown immunity
and found many applications particularly in audio power amplifiers and
linear power supplies. Other companies tried to copy it with varying
degrees of success: one company acknowledges it now by naming a power
MOSFET after it. We trace its history, manufacture and eventual decline
against pressure from competing technologies. Modern simulation tools
have been used to investigate the operation of the device which
illustrate its good, and not so good, features. We also relate its
geometry to a SPICE model. Neither of these tools would have been
available to the original developers. We propose that this transistor be
given a place in the archives of history, ranked alongside other famous
devices of the 20th century such as the 300B tube."
http://ieeexplore.ieee.org/Xplore/login.jsp?url=/iel5/16/20748/00960371.pdf?arnumber=960371
"You can build good amps with 2N3055/MJ2955's and they are pretty cheap.
I've built a <.01% amp @50W using them which sounds great.
Many people think these are past their sell-by date, but I think that
they are still OK as a starter.
The old hometaxial RCA 2N3055 was slow (800kHz) and had a large gain
variation (non-linearity) ranging between (say) 120 at 100 mA and 30 at
4A. This was a problem in many 1970's amps which did not have enough
gain to linearise the outputs with feedback. For example if your open
loop gain is 2000 and closed loop 30, as defined by the feedback ratio,
the actual gain will be around 29.6. But if the open loop gain changed
to 8000 the closed loop gain becomes 29.92. That represents a distortion
level of 1%. No wonder many amps sounded different. You can't get these
RCA devices anymore, but ST and ON Semi still sell 2N3055/MJ2955's.
So you need a high open loop gain, and you should get good performance.
You can use Miller compensation if you are careful about the input stage
(see tcpip's forum), but JLH's method seems to be better.
The latest 2N3055 from ON Semi is similar, I suspect, to their MJ15003/4
processing. The SOA of the 2N3055 is up to 40V at 115W, and 60V at about
1A which is higher than any previous epitaxial 2N3055. And, they'll
usually be fine up to +/- 38V power supplies for 60W amps, better than
the SOA I have seen for TIP3055/TIP2955.
They have an fT around 2.5 MHz which is similar to MJ15003/4."
http://www.diyaudio.com/forums/showthread/t-93633.html
bottom of page
Incidentally, the Vcer figure of 70V is most appropriate to the majority
of applications.
Graham
E
Eeyore
Guest
Phil Allison wrote:
Graham
800W both channels."Eeysore the Professional LIAR "
They were a damn sight pricier than 2N3055s I can tell you. I still have
part of a tray of them left over from when I did repairs more often.
Actually not
a bad device at all for its day. It's why 800W per channel became a sort of
'standard' for PA/SR power amplifiers into 4 ohm loads for ages.
** OK - lets see you list a couple of popular models of audio power amp
that used only 2N3773s for outputs and were rated at 800 wpc into 4 ohms.
Graham
P
Phil Allison
Guest
"Eeysore"
** Is that a correction of your error ?
....... Phil
Phil Allison wrote:
"Eeysore the Professional LIAR "
They were a damn sight pricier than 2N3055s I can tell you. I still
have
part of a tray of them left over from when I did repairs more often.
Actually not
a bad device at all for its day. It's why 800W per channel became a
sort of
'standard' for PA/SR power amplifiers into 4 ohm loads for ages.
** OK - lets see you list a couple of popular models of audio power amp
that used only 2N3773s for outputs and were rated at 800 wpc into 4 ohms.
800W both channels.
** Is that a correction of your error ?
....... Phil
E
Eeyore
Guest
Phil Allison wrote:
800C for example. These were only outrated at the time by moving to the new
Hitachi lateral mosfets, hence the very popular 'Mosfet 1000'. I later designed
a 600 wpc amp for them (1200B) using selected (200V) Hitachi devices. The yield
was good enough for it to be an economic choice.
Graham
It was my error, freely acknowledged. As used in the RSD / Studiomaster 800B and"Eeysore"
Phil Allison wrote:
"Eeysore the Professional LIAR "
They were a damn sight pricier than 2N3055s I can tell you. I still
have part of a tray of them left over from when I did repairs more often.
Actually not a bad device at all for its day. It's why 800W per channel
became a
sort of
'standard' for PA/SR power amplifiers into 4 ohm loads for ages.
** OK - lets see you list a couple of popular models of audio power amp
that used only 2N3773s for outputs and were rated at 800 wpc into 4 ohms.
800W both channels.
** Is that a correction of your error ?
800C for example. These were only outrated at the time by moving to the new
Hitachi lateral mosfets, hence the very popular 'Mosfet 1000'. I later designed
a 600 wpc amp for them (1200B) using selected (200V) Hitachi devices. The yield
was good enough for it to be an economic choice.
Graham
P
P.
Guest
On Wed, 10 Dec 2008 23:05:25 -0800, DaveC <me@bogusdomain.net> wrote:
And they are getting better at it by the day. I think they somehow get
into larger manufacturing plants. I have some microprocessors here
that were even lasermarked and were sent to me as free samples. They
(Chinese of course, who else) were probably hoping that we wouldn't
test them.
An example: Motorola. They sold the transistor division to ON
Semiconductor several years ago. And check ebay: new expensive
motorola transistors are offered there, they are ALL fake!
Sometimes there actually is a chip inside, but a small one. So it may
test ok but will be destroyed when you really when them to deliver
power.
Another thing the chinese do is taking out parts out of scrapped
equipment. They clean them, re-solderdip them etc. Often you can't see
it. But the parts are used. They may work, they may not.
And another thing they do is repacking parts that were rejected in
productionlines. Many parts ar made in Asia, the scrap is sent to
certain companies specialized in scrapping. But they just repack them
and sell them as new. Notice that these are rejected and potentially
(in medical equipment etc) dangerous parts!
And what they do too is remarking. They take normal processors and
make a military one of it by remarking them. On your testbench they
will test ok. But at for example extreme temperatures they will fail.
Would you like to be in an airplane controlled by such parts?
One of the causes is, just like with the crisis we have now, GREED.
Companies over here buy that scrap and sell it here to make large
profits. There are several companies in the US that cannot be trusted
anymore.
Stick with reliable ones like RS, Farnell, Mouser etc. That should be
safe.
P.
Yes. ALL components are being counterfeited in China nowadays.I need to buy some '3055's. Is there much risk of getting a counterfeit? I
read that because these are so cheap, they are being substituted (and
relabeled) for more expensive transistors. But there's not much profit in
counterfeiting 3055's.
Should I be concerned?
Thanks,
And they are getting better at it by the day. I think they somehow get
into larger manufacturing plants. I have some microprocessors here
that were even lasermarked and were sent to me as free samples. They
(Chinese of course, who else) were probably hoping that we wouldn't
test them.
An example: Motorola. They sold the transistor division to ON
Semiconductor several years ago. And check ebay: new expensive
motorola transistors are offered there, they are ALL fake!
Sometimes there actually is a chip inside, but a small one. So it may
test ok but will be destroyed when you really when them to deliver
power.
Another thing the chinese do is taking out parts out of scrapped
equipment. They clean them, re-solderdip them etc. Often you can't see
it. But the parts are used. They may work, they may not.
And another thing they do is repacking parts that were rejected in
productionlines. Many parts ar made in Asia, the scrap is sent to
certain companies specialized in scrapping. But they just repack them
and sell them as new. Notice that these are rejected and potentially
(in medical equipment etc) dangerous parts!
And what they do too is remarking. They take normal processors and
make a military one of it by remarking them. On your testbench they
will test ok. But at for example extreme temperatures they will fail.
Would you like to be in an airplane controlled by such parts?
One of the causes is, just like with the crisis we have now, GREED.
Companies over here buy that scrap and sell it here to make large
profits. There are several companies in the US that cannot be trusted
anymore.
Stick with reliable ones like RS, Farnell, Mouser etc. That should be
safe.
P.
P
P.
Guest
On Thu, 11 Dec 2008 06:25:52 -0500, Spehro Pefhany
<speffSNIP@interlogDOTyou.knowwhat> wrote:
Can I have a foto of that? I am collecting data on fake parts.
We are developing good replacement parts, and I am making a list of
fake parts to show my customers. So they know what is out there.
P.
<speffSNIP@interlogDOTyou.knowwhat> wrote:
Hi,On Thu, 11 Dec 2008 02:12:00 -0800, the renowned PhattyMo
phattymo@not.net> wrote:
Phil Allison wrote:
"DaveC"
I need to buy some '3055's. Is there much risk of getting a counterfeit? I
read that because these are so cheap, they are being substituted (and
relabelled) for more expensive transistors. But there's not much profit in
counterfeiting 3055's.
Should I be concerned?
** Well, I have bought counterfeit BC639s for 30c each - they were very
likely reject BC547s relabelled.
The aim of the counterfeiter is sell devices he can get for almost nothing
that near impossible to sell and make a killing by falsely re-labelling
them.
2N3055s are still very popular and so easy to sell - but lots of other
old, oddball TO3 types are not.
Expect fakes to be offered on eBay and elsewhere.
..... Phil
'They' are faking everything now. There have been incidents of caps
being faked too.
I have a bag of 1,000 fake Panasonic trimpots.
Best regards,
Spehro Pefhany
Can I have a foto of that? I am collecting data on fake parts.
We are developing good replacement parts, and I am making a list of
fake parts to show my customers. So they know what is out there.
P.
P
P.
Guest
On Thu, 11 Dec 2008 09:41:59 -0500, "Michael A. Terrell"
<mike.terrell@earthlink.net> wrote:
Our provider blocks binary email groups. Can you post them elsewhere?
P.
<mike.terrell@earthlink.net> wrote:
hi,Spehro Pefhany wrote:
On Thu, 11 Dec 2008 02:12:00 -0800, the renowned PhattyMo
phattymo@not.net> wrote:
Phil Allison wrote:
"DaveC"
I need to buy some '3055's. Is there much risk of getting a counterfeit? I
read that because these are so cheap, they are being substituted (and
relabelled) for more expensive transistors. But there's not much profit in
counterfeiting 3055's.
Should I be concerned?
** Well, I have bought counterfeit BC639s for 30c each - they were very
likely reject BC547s relabelled.
The aim of the counterfeiter is sell devices he can get for almost nothing
that near impossible to sell and make a killing by falsely re-labelling
them.
2N3055s are still very popular and so easy to sell - but lots of other
old, oddball TO3 types are not.
Expect fakes to be offered on eBay and elsewhere.
..... Phil
'They' are faking everything now. There have been incidents of caps
being faked too.
I have a bag of 1,000 fake Panasonic trimpots.
Can you post a picture of them, and the real Panasonic pots on
news:alt.binaries.schematics.electronic
Our provider blocks binary email groups. Can you post them elsewhere?
P.
F
f825_633
Guest
P. wrote:
have strict procedure. Every part can be directly related
back to its point of manufacture - thats why Mil-Spec is so
bloody expensive, I can see it would be tempting financially
for a suppler to trade non-authentic or copy parts but it
would be difficult to reproduce the required history for
such a part to be able to supply it in the first place.
In Aviation every part is in its own bag with a specific
number that points to a huge paperwork trail and when its
fitted to a piece of equipment the paperwork is then
included within the aircraft manual, its not unusual for a
singular aircraft to gave several filing cabinets of
history. I've worked on aircraft communications equipment,
it can 10 minutes to fix the equipment and then another hour
to fill in the paperwork. No Certificated engineer is going
to risk his qualification fitting a part he cannot
substantiate as being authentic with the relevant paperwork,
it just too expensive and takes too long to get the
accreditation in the first place to risk it for a few pounds.
Not sure about Medical; But the MOD and Aviation industriesOn Wed, 10 Dec 2008 23:05:25 -0800, DaveC <me@bogusdomain.net> wrote:
And another thing they do is repacking parts that were rejected in
productionlines. Many parts ar made in Asia, the scrap is sent to
certain companies specialized in scrapping. But they just repack them
and sell them as new. Notice that these are rejected and potentially
(in medical equipment etc) dangerous parts!
And what they do too is remarking. They take normal processors and
make a military one of it by remarking them. On your testbench they
will test ok. But at for example extreme temperatures they will fail.
Would you like to be in an airplane controlled by such parts?
have strict procedure. Every part can be directly related
back to its point of manufacture - thats why Mil-Spec is so
bloody expensive, I can see it would be tempting financially
for a suppler to trade non-authentic or copy parts but it
would be difficult to reproduce the required history for
such a part to be able to supply it in the first place.
In Aviation every part is in its own bag with a specific
number that points to a huge paperwork trail and when its
fitted to a piece of equipment the paperwork is then
included within the aircraft manual, its not unusual for a
singular aircraft to gave several filing cabinets of
history. I've worked on aircraft communications equipment,
it can 10 minutes to fix the equipment and then another hour
to fill in the paperwork. No Certificated engineer is going
to risk his qualification fitting a part he cannot
substantiate as being authentic with the relevant paperwork,
it just too expensive and takes too long to get the
accreditation in the first place to risk it for a few pounds.