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Old 9th August 2012, 12:43 PM   #21
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Hi Triplej, I think what homemodder is saying that we always stock the real part when it comes to our favorite semi conductors.

I buy by a box or tray or tape, 100 or 300 or 1000 at a time. You obviously don't test every one, but you do test at least one of the batch. This is simply referred to as incoming goods quality inspection, if it is not right you reject the lot and give it back to the supplier.

Most DIYer buy only a few parts for a particular project and this is partly the reason that they are done in because they buy from any buying house. When you get to know your supplier's quality standards you will go back to the same supplier and you start getting consistent quality supply.

There are many well known and some even respected buying houses that will buy up bulk reject stock for resale at next to nothing to make a quick buck, so you always need to be careful.
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Old 9th August 2012, 12:47 PM   #22
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Quote:
Originally Posted by triplej View Post
You perform SOA and vce tests on all the transistors you buy to decide if they are fakes or not? Wow.
Only when in doubt and the parts dont look like a batch that I saw previously, conform to datasheet physical marks or batch mumbers or the design doesnt perform as expected. I dont need to go that far much nowadays as visual inspection is usually enough but it took some years of experience to be able to discern.
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Old 9th August 2012, 12:51 PM   #23
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Some time ago i bought some MN3005 BBD chips from utsource. They worked pretty well and I'm pretty sure they aren't fake. From ebay I got really bad experiences. They always refunded my money, though.
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Old 9th August 2012, 11:21 PM   #24
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Thanks Nico
My comment re the SOA testing was a bit tongue in cheek.
I was simply trying to point out two things to Diy Didi
1) Not all components sourced from HK are fakes as some on this forum would have you believe. My experience has been positive overall.
2) Renasis / On Semi / NXP etc are not fakes, they are legitimate products. They may not have as stringent QA as the OEM but they are fit for purpose.
My MPSA’s are MPSA’s and my 2SJ’s are 2SJ’s. My amps do not explode.
J

Last edited by triplej; 9th August 2012 at 11:25 PM.
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Old 10th August 2012, 08:50 AM   #25
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Quote:
Originally Posted by triplej View Post
Thanks Nico
My comment re the SOA testing was a bit tongue in cheek.
I was simply trying to point out two things to Diy Didi
1) Not all components sourced from HK are fakes as some on this forum would have you believe. My experience has been positive overall.
2) Renasis / On Semi / NXP etc are not fakes, they are legitimate products. They may not have as stringent QA as the OEM but they are fit for purpose.
My MPSAs are MPSAs and my 2SJs are 2SJs. My amps do not explode.
J
In point (2), are you simply saying that since these guys may be legitimate second sources it should be OK to use their products with the same performance expectation for the OEM part?

I think there is enough evidence on this forum that such a degree of parts interchangeability doesn't often apply even to legitimate semi knock-offs. However, the issue here is really about counterfeit parts. i.e those that not only prove to be something other the original part but are marked and marketed fraudulently.

Surely, if you find high cost parts at bargain prices, whether via Ebay or any marketing house, you run a high risk that yours will be fake parts and many customers will be helpless, not even understanding what verification tests should be used to justify a refund and the hassle. If you want to repair someone's gear or build with any confidence that your project is going to perform like the simulation, textbook or someone else's prototype, you must at least be very certain of your component quality. That is just common sense.

It seems there are always individuals attracted principally to lowest prices, whatever the risk. If we saw these parts sold cheaply next to genuine parts in a retail outlet, we probably would steer clear of them but the nice pics and words on Ebay seem to inspire confidence, don't they?

Well, for my money, there are better options and much lower risks, even at twice the price. Guys, don't be so easily sucked-in.
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Old 10th August 2012, 10:43 AM   #26
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Quote:
Originally Posted by triplej View Post
Thanks Nico
My comment re the SOA testing was a bit tongue in cheek.
I was simply trying to point out two things to Diy Didi
1) Not all components sourced from HK are fakes as some on this forum would have you believe. My experience has been positive overall.
2) Renasis / On Semi / NXP etc are not fakes, they are legitimate products. They may not have as stringent QA as the OEM but they are fit for purpose.
My MPSA’s are MPSA’s and my 2SJ’s are 2SJ’s. My amps do not explode.
J
BTW Renasis, On Semi, and NXP are only second source to a very small number of parts, mostly their products are the OEM. When they manufacture second source parts they buy licencing if the original OEM still has the part in production. These companies comply to stringent quality control even with the second source parts and therefore these parts in nearly all cases are as good as the OEM. In these cases the parts are marked as being their own (not the OEM s), which is a first clue about quality while the Hong Kong and China parts mark the parts like the originals as they have to fool the public to purchase them as 99.99 % dont conform the specifications.

I think you missing the point a little and Ian s post clarifies the topic.
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Old 13th August 2012, 01:34 AM   #27
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Yes maybe too much focus on the post OEM manufacturers but I have seen Renasis 2SJ / 2SK referred to as fake.

I also wanted to correct statements like this elsewhere on this forum:

I would not buy any critical components from China, transistors, capacitors, resistors, chips, etc. Especially on eBay. Guaranteed to be 99.9% fake.

Thats simply ridiculous.

DIY Didi: Id be interested if you proceed, what your experience is.
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Old 13th August 2012, 12:02 PM   #28
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They do fake them though, by remarking. Its simple take IRFp240 (cheap) remark as 2SJ200
(more than double the price and make easy money.

Care to post pics of all the transistors you bought off of ebay, Ill point you the fakes or inferior second source parts if any ??
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Old 16th August 2012, 11:30 PM   #29
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Here are some. One's a bit blurry but i cant be bothered redoing..

BTW even my "inadequate" testing would pick the difference between an irfp240 and 2sj200.
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Old 17th August 2012, 12:38 AM   #30
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I have bought about 50 SSM2044 from utsource which are quite a common fake item. One was dead, the others were all fine.
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