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Old 16th April 2010, 03:57 PM   #11
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Quote:
Originally Posted by fredlf View Post
This thread has been moved from where it began..

Here are the facts I have ascertained testing the 2SC2912's I received from MCM.

I ordered these twice, several weeks apart.

I tested three from the first order with a 160v Lceo test. All failed, allowing over 5.5 amps of leakage.

I tested one from the second order. It failed spectacularly, going full open in a few seconds. I did not test any others in order to protect the amp power supply I was using and myself.

In fairness, I did buy two Toshiba 2SD424's and both passed the high voltage Lceo test with 0 leakage.

The "original" in the pic is the original factory part pulled from my Adcom.
Hi

I purchase sanyo transistors via a agent directly from sanyo. In the pic you posted only the top 2sc2912 is the real deal, the other 2 are fakes. Sanyo deliberatly mark their transistors in that way so that it can be descerned from fakes. If any sanyo to220 transistor doesnt look like the first example youve shown its fake according to what the sanyo sales office has told me. Look at the slightly different colour square around the markings and the shallow but larger circumference circle. Their to3p parts use very similar markings, for to92 parts its a little harder to discern, you have to look at the indentions at the back of the transistor.

Ive purchased from MCM before mostly Sanyo transistors, its the first time Ive seen a fake from them but obviously it could happen, still I would highly recommend MCM for purchasing of parts.

Last edited by homemodder; 16th April 2010 at 04:04 PM.
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Old 16th April 2010, 04:29 PM   #12
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I have been Purchasing Sanken transistors from Bdent.com and all have worked for my applications. I have been cautious to test devices as well as i can before installing them. I even emailed Bdent to ask what there policy was for fakes. they responded with the generic "well we have never had a problem so far" type of response. but i am still cautious with what i buy/use. anyone have good/bad experiences there?
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Old 16th April 2010, 06:38 PM   #13
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Hi Zero Cool,
You have to assume control over your own quality. That means examining and testing your own parts as they arrive. It's been shown time and time again that if you push the responsibility for QC up the chain, eventually you will get burned.

I think it went something like this. Distributors decided they didn't want to pay for skilled employees. So they worked a deal where the manufacturer shoulders the responsibility for QC. This works okay for as long as the manufacturer makes the parts themselves (as opposed to a "fabless" company) and the distributor only buys from the distributor (or sales office). Next, a salesperson decides that the parts are cheaper from a different source (supposed overstock inventory or other supply outside the control channel) and procures them. Having no internal QC as a possible issue never occurred to anyone. Basically a number of accountant type decisions that moved the company away from being responsible. In short, a real business person knows the intangible they are selling is the assurance of quality. Bean counters don't understand business as much as they say they do, so you end up in this situation. The lie in this scenario is the assurance of top quality from the sales organization without any means to ensure that this is what they are delivering. They made an actual decision to eliminate the cost of quality control, passing the risk for the series of decisions on to the end users.

Now, what would the reaction be if this occurred with medical devices or drugs? Oh, wait. This has happened. It's all about basic greed folks. The myth of high quality at a bargan price that shareholders like to hear. I also believe that this is part of the reason for the economic problems that the 'States is suffering now. The way that new business leaders have been interpreting how they should run a business. There has even been a need to create a law to re-enforce using good business practices, 'cause they forgot how to do that too. Thinking Sarbanes-Oxley here. It's amazing how many companies are not compliant.

-Chris
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Old 16th April 2010, 07:14 PM   #14
davada is offline davada  Canada
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The problem has to stopped at the source. These parts are purchased from legitimate dealers and so there has to be paper trail back to the source. If this was counterfeit money or a ponzi scheme it would have been cleaned up a long time ago. Why is there no support from government? Both commodities and money have nearly the same value.

I was warned about this problem by an electrical engineer in the early 80s that's almost 30 years ago. So why is it that we are still plagued with the problem? As far as I know counterfeiting of any kind is illegal.

David.
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Old 16th April 2010, 07:56 PM   #15
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The counterfeit parts problem has generated another problem for me. I have a great deal of money tied up in parts that I can no longer use, but everyone is so scared of counterfeit parts that I can't sell them, even at a substantial loss.
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Old 16th April 2010, 08:16 PM   #16
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Hi David,
The other entry point for contaminants is return of materials. The entire chain must be protected from source to end user. Education is the best weapon, but there must be a will to change the way business is done. Typically the will is only brought about by financial loss. That's the only way to get in touch with the people making decisions.

This issue concerns everyone, including the small parts vendors and service shops. I can say from experience that the greatest amount of fake parts is in the TV / VCR sector. Right from the distributor to the TV shop. Anyone who doesn't care about anything but profit margin alone. I know of a well known distributor in Canada that has knowingly and willingly sold parts they know to be not genuine. Complaints were received by their legitimate suppliers and nothing was done to the best of my knowledge. This probably continues to this day unabated. I have first hand knowledge of this and some of the people involved.

To be honest, this entire mindset began with replacement semiconductors. GE and similar branded material seemed to be okay, but ECG parts were complete trash. Where I worked at the time, I was only allowed to use what we sold for service. It was so bad I stuck the leads through the bags and measured the parts myself (using a Heathkit IT-18, still use it). What happened with the ones I rejected? They didn't go back up the chain. It was a one-way street. No, customers bought them, and they were mostly TV repair shops and some industrial customers. I felt terrible about this, but I had my orders from management. Eventually I was able to bring in industry part numbers. My repair returns dropped to next-to-nothing as soon as I began using "real" parts. The manager began selling these parts at ECG prices, greedy so-and-so!

Anyway, once TV guys and industrial maintenance people accepted remarked parts (and paying a premium for them!), the door was open for others to follow suit. Eventually the advice was "only buy original part numbers". Well, our shady suppliers were happy to oblige us by erasing the original numbers and marking on the higher valued part number. Some were a little sleazy, like an MJ15015 marked as an MJ15024. The cases were different as was the marking style. We got to recognize the cases and markings. It was odd seeing the first Japanese fakes, Japanese numbers on a Motorola case. What a lame attempt! But, they actually were accepted by ... the TV shops or other untrained personnel. Go figure. As the fakes became more difficult to spot visually, we began testing the parts to determine real or not. This all happened in the later 70s and early 80s. Long before this time for sure.

The only reason we wanted to be able to identify fake parts was to be able to prove to the customer the reason for his set breaking down so many times. This was to regain some confidence for that customer that we were actually going to repair his item. This root problem (greed) has cost the service industry it's reputation and trust. I have to say the dishonest people worked pretty hard to trash the industry.

As long as there are greedy people out there, there will be re-numbered parts available to fill the demand. Greed is an inherent part of human society, so it will be extremely difficult to eliminate these issues.

-Chris
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Old 16th April 2010, 08:21 PM   #17
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Hi Steve,
Yes. That is an unfortunate truth. It has cost every single honest person something, and many customers too.

Old stock parts are difficult to sell at the best of times. With this added problem, I don't know how this will end for you. What date codes are you looking at there? For our members, these may predate the really good fakes (so are a safer buy).

What do you have on hand? MJ15003 / MJ15004 or MJ15022 ~ MJ15025? If you have MJ15015 / MJ15016 - burn them.

Best, Chris
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Old 16th April 2010, 08:59 PM   #18
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Hi Chris,

I had 93 each of the MJ15024/5 that I sold this week for $1 each. I have about 50 each of the discontinued NEC 2SB600 and 2SC555 that everyone is afraid to buy these days. I don't know the date codes on them, but I bought in large quantity them over 15 years ago. I would have to have my wife do some inventory for me before I could tell you much more. Remember, it has been three years since I did anything in my shop.

Last edited by Steve Dunlap; 16th April 2010 at 09:01 PM.
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Old 16th April 2010, 09:09 PM   #19
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Hi Steve,
Yes, I know you aren't very mobile. I'm more trying to help get the information out.

$1 each for those transistors is one heck of a deal! Especially since they are still current and useful. I know the 2SB600 and 2SD555 were not inexpensive when you bought them as well. Being a Japanese number, I can see why there is reluctance to buy them. That and the MJ numbers are realistically more useful in the average amplifier. At one time, those were the highest rated power transistor out there. Probably faster than the Motorola stuff at the time as well. Did you ever test them to see if they had less "gain droop" than the Motorola parts?

Best, Chris
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Old 16th April 2010, 09:23 PM   #20
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I only ran curves on them for the operating conditions I was using them at. That was at 50V and 4A. They looked very good, far better than the Motorola's I was testing back then. Also in a lot of 100 the Motorola's could have a variation in gain of a factor of 2.5 to 3. The NEC's were with in 10% for a lot of 100.
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