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Jason Bowden

RC in Front of the Op-Amp: Why Did It Fail?

Jason Bowden
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goafrit2
goafrit2
2/14/2013 6:14:48 PM
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Master
Re: Fake parts
>> Some of the selling of out of spec parts is not condoned but happens due to poor audting control as well.

This seems to be a well-structured business model for many U.S. firms. They simply name the product something different and sell it. However, they are very carefull to update the datasheets accordingly.

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goafrit2
goafrit2
2/14/2013 6:12:47 PM
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Master
Re: Fake parts
>>  Not all buyers are aware when lower grade parts

Do you think we need to have more disclosures on this? I think it may be necessary in the industry.

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eafpres1
eafpres1
1/28/2013 6:37:41 PM
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Blogger
Re: Fake parts
goafrit2 you raise a good point.  There are some variations.  In some cases, there are parts that have a range of performance due to tolerance variations and process variations.  Sometimes companies sort the parts and offer different grades.  Not all buyers are aware when lower grade parts (say, they might not meet the top grade temperature specs) are being offered to them.

It has been a problem with contract manufacturing that "scrap" goes out the back door.  I would say in my experience this has decreased in the last 10 years in China, but it depends a lot on who you are dealing with.  Auditing is required to stop this.

Another issue is factory buyers at CM or even company-owned sites in China etc. may do things they should not do to manage cost.  Often they are highly incentivized to "save" and will trade quality for price with suppliers.

Some of the selling of out of spec parts is not condoned but happens due to poor audting control as well.  I would say that an out of spec part sold onto the broker market is equivalent to counterfeit.

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goafrit2
goafrit2
1/28/2013 6:08:01 PM
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Master
Re: Fake parts
>> We found some of them were molded from low grade polyethylene. 

I have worked in the industry and noticed that companies sometimes have bad production. Say, they have a big order. They produce and quality is not met. They need to redo it. However, instead of throwing away the parts, they sell it to mass market. It happens. Sometimes the products are not fake, it is just that companies want to make money from compromized parts.

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goafrit2
goafrit2
1/28/2013 6:05:10 PM
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Master
Re: The counterfeit part problem
>> As engineers we have trouble understanding the mindset of someone who will compromise their integrity for a few hundred bucks.

Sure but engineers in this age are seeing a lot of things. Who can swear with his CEO? These days guys are not even sure when their CEOs are speaking the truth because he will email the whole staff that there will not be layoffs only to cut 10% next week. That said, any engineer that does not understand that people can do anything for money is in trouble.

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goafrit2
goafrit2
1/28/2013 6:02:43 PM
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Master
Re: Fake parts
>> Yeah but once they leave the plant, noone can really control what they get mixed in with.

It is indeed a supply chain issues which can be controlled if the distributors are serious. If you decide to buy from only authorized distributors, this problem will be solved.

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DadOf3TeenieBoppers
DadOf3TeenieBoppers
1/28/2013 3:49:23 PM
User Rank
Teacher
The counterfeit part problem
I too have had a run-in with counterfeit parts. A board that had failed in the field after many long years of service, and was no longer in production, had to be repaired. Our technician easily figured out what had failed (a Uni-junction transistor that was no longer in production). But when he replaced the part, several times I might add, without getting it to work again, they gave it to engineering.

I replaced the part one more time with the same dismal results. It was then that I noted the failed parts both failed identically, which was odd; they behaved like regular bipolar transistors, rather than a dead short or dead open like a failed part should. Checking with the technician confirmed this.

I quickly figured out that we had received a batch of counterfeit parts remarked to look like the unijunction transistor. After alerting components engineering (who subsequently blacklisted the vendor we got them from) we found six parts in an old warehouse our company owned overseas. Two were shipped to me, and on the first attempt, the board worked again!

As engineers we have trouble understanding the mindset of someone who will compromise their integrity for a few hundred bucks. It is disturbing that they are out there. Will we have to wait for the 2nd coming for them to recieve their just desserts?

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eafpres1
eafpres1
1/27/2013 1:19:10 AM
User Rank
Blogger
Re: Fake parts
When I was with a company making antennas for WLAN high-end access points, we once had TNC connectors where the inner dielectric melted and deformed during the application of heat shrink tubing.  We found some of them were molded from low grade polyethylene.  

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Jason Bowden
Jason Bowden
1/26/2013 11:20:53 PM
User Rank
Newbie
Re: Fake parts
Yep,had an issue of connectors that looked exactly like my suppliers but they melted at low temp. Come to find out they really weren't V0 rated material. Thanks to a nice material analysis.

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Jason Bowden
Jason Bowden
1/26/2013 11:18:00 PM
User Rank
Newbie
Re: Fake parts
Yeah but once they leave the plant, noone can really control what they get mixed in with. It then becomes up to the disty or whoever to make sure they are not taking parts from unauthorized people.

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<<   <   Page 2 / 4   >   >>
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