Sourced those from ebay. The one that I opened burned at the first 2 minutes on the pcb.
I am sure those are not the real think. Lesson learned the hard way. Thankfully only a resistor was burned together with the fake transistor.
At work I have seen thousands of the ON MJL1302/MJL3281 over the years. Without fail they have always looked like the top and bottom left transistors in your photograph right down to the font, size and position of the printing.
Normally I am careful not to judge by looks alone, but in this case I'd be fairly certain that the bottom right one is indeed a fake.
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"SC5200+2SA1943" from Toshiba with Runaway of the adjusted Idle Current Value
By the repair of the damaged pure class-A integrated amplifier Luxmann (Luxmann) L550 (L 550) I note, that the shortly ordered output devices from Toshiba (about Nedis) don't work how they actually must.
The behaviour is exact in that kind, as if I had not screwed the transistors on the heatsink (respectively as if I had used thermal isolated insulating slices - but I use mica washers).
This means, the internal chip haven't contact to the die.
I guess, I have fakes resp counterfeits, although from the typeface (kind of font) nothing is striking to see.
How I can open this kind of outline (seems to be more difficult than TO-3) ?
Are there such observations were already made?
Thank you for your comments.
By the repair of the damaged pure class-A integrated amplifier Luxmann (Luxmann) L550 (L 550) I note, that the shortly ordered output devices from Toshiba (about Nedis) don't work how they actually must.
The behaviour is exact in that kind, as if I had not screwed the transistors on the heatsink (respectively as if I had used thermal isolated insulating slices - but I use mica washers).
This means, the internal chip haven't contact to the die.
I guess, I have fakes resp counterfeits, although from the typeface (kind of font) nothing is striking to see.
How I can open this kind of outline (seems to be more difficult than TO-3) ?
Are there such observations were already made?
Thank you for your comments.
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What do you make out of those JFakes, eh sorry, JFets?
They measure ~6mA in majority. Got just a few to check out. Legs longer than other Tosh, x mark inside the back circle unlike other Tosh having none. Unless they packaged any outside Japan, they are highly suspicious... Is anybody having any J74s looking like those, knowing more?
They measure ~6mA in majority. Got just a few to check out. Legs longer than other Tosh, x mark inside the back circle unlike other Tosh having none. Unless they packaged any outside Japan, they are highly suspicious... Is anybody having any J74s looking like those, knowing more?
Attachments
by the horizontal scratching across the face as if the case was shaved, i would say they are fakes. the font and everything else looks corerect, but the surface finish is not original.... upon further inspection the dot in the date code is too far to the left of the date code digits. it looks like * 7A when it should look like *7A
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Clamp the transistor with the wires in a bench vice and with a knife and hammer split the 2 halves. With a little luck it opens nice..
Good luck, Loek
What do you make out of those JFakes, eh sorry, JFets?
They measure ~6mA in majority. Got just a few to check out. Legs longer than other Tosh, x mark inside the back circle unlike other Tosh having none. Unless they packaged any outside Japan, they are highly suspicious... Is anybody having any J74s looking like those, knowing more?
I had similar typeface on the 2SJ74 JFakes made by laser burning (or some other artifice) of the letters in the plastic, with rough edges in the letters. I would not trust them
I got same leg model. And I did not buy cheapo.
albert
Thanks - yes this is so. Size of die looks correct.
How I can check the internal thermal resistance between the die and the metal heatsink face by a device, that is yet not damaged ??
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That fake one looks like I molded it in my garage, and like there isn't 20 Watts worth of die in there! The worst I've ever seen.
fake alert...
some devices i've run across recently that are faked in large numbers...
SANKEN (SK logo)
2SD2390
2SB1560
2SB1647
2SD2560
MN2488 (made by sanken for sony) also 2SD2488
MP1620 (made by sanken for sony) also 2SB1620
these are darlington outputs used in the majority of mid grade multichannel A/V receivers for the last 10 or so years (Denon, Sherwood, Pioneer, Harmon Kardon, Marantz, some Onkyos). many of these parts can be quickly identified as fakes visually, but capacitance, leakage, Vbe, and beta tests are the best way to tell. these parts are flooding the market primarily through repair parts distributors. these are not really expensive or fancy transistors, but the sheer numbers of them being used in receivers seems to be the draw for counterfeiters to fake them. one of the largest dangers in using them is that they are a fire hazard. when the original sanken devices short, they rarely even smoke. when these fakes fail, they catch fire and emit showers of sparks (yes, like fireworks). if you see it happen it is quite spectacular. if it happens in a customer's home and starts a fire, you may have a lot to worry about.
while we're on the subject. if you are having difficulty getting a distributor to make good on selling you fakes, make them aware of the ramifications of these parts burning someone's house down. you may have put these transistors in, but you are small potatoes compared to a parts distributor.
some devices i've run across recently that are faked in large numbers...
SANKEN (SK logo)
2SD2390
2SB1560
2SB1647
2SD2560
MN2488 (made by sanken for sony) also 2SD2488
MP1620 (made by sanken for sony) also 2SB1620
these are darlington outputs used in the majority of mid grade multichannel A/V receivers for the last 10 or so years (Denon, Sherwood, Pioneer, Harmon Kardon, Marantz, some Onkyos). many of these parts can be quickly identified as fakes visually, but capacitance, leakage, Vbe, and beta tests are the best way to tell. these parts are flooding the market primarily through repair parts distributors. these are not really expensive or fancy transistors, but the sheer numbers of them being used in receivers seems to be the draw for counterfeiters to fake them. one of the largest dangers in using them is that they are a fire hazard. when the original sanken devices short, they rarely even smoke. when these fakes fail, they catch fire and emit showers of sparks (yes, like fireworks). if you see it happen it is quite spectacular. if it happens in a customer's home and starts a fire, you may have a lot to worry about.
while we're on the subject. if you are having difficulty getting a distributor to make good on selling you fakes, make them aware of the ramifications of these parts burning someone's house down. you may have put these transistors in, but you are small potatoes compared to a parts distributor.
Here is a very interesting article about counterfit electronic components in US weapon systems:
U.S. Senate Panel Targets Counterfeit Electronic Parts - Defense News
Disturbing news indeed.
U.S. Senate Panel Targets Counterfeit Electronic Parts - Defense News
Disturbing news indeed.
this is even more disturbing... just finished reading it...
http://www.eetimes.com/electronics-...eiting-case-exposes-defense-supply-chain-flaw
http://www.eetimes.com/electronics-...eiting-case-exposes-defense-supply-chain-flaw
you can buy ON (formerly Motorola) parts from Newark Electronics (or in other countries "Farnell")
i think you can find authorized distributors by looking on the manufacturer's web site.
for instance i did a price and availability search for MJ15024 transistors, and on the right hand side are links to distributors that sell them for onsemi.
Semiconductor Pricing and Availability
toshiba's web site has this:
Sales Contacts - United States - Toshiba America Electronic Components and Semiconductors
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since they are some of the most common small signal transistors used in amps that are currently being produced, i wouldn't be surprised. i average about 10-20 per week of each of these repairing amplifiers. for the 2SC2240, there is a korean version of this part, the KTC3200. the specs are IDENTICAL. the only problem is that the korean part has a high failure rate from C-E leakage. they also develop thermal problems. don't get me wrong, the KTC3200 has EXACTLY the same ratings as the 2SC2240, so technically, it's a valid replacement, but it's reliability is awful. my guess is that KEC licensed the process from Toshiba for making these transistors (KEC licenses a lot of semiconductor processes from other manufacturers), but Toshiba wouldn't license the part number because of the reliability issue. So KEC had to get a different number (3200 instead of 2240). i wouldn't be surprised if somebody is buying up KTC3200 devices and re-labeling them as 2SC2240.
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Hi unclejed613,
All these fake parts are really old news - really old. At least now the major distributors are taking strong steps to keep the fakes out of the normal supply system. These fakes actually became noticed in the TV repair business. I think the first large scale copy was the Sony SG613 SCR. I think I have that part number right. Anyway, the TV service field is strongly price driven and staffed by mostly uneducated (to the level required in other fields) service people. There is also a high rate of very low moral ethics and down right thieves. In this environment, fake parts couldn't help but to be an extremely profitable business. Back in the 80's, there were people in New York operating semiconductor labelling machines. They weren't manufacturing semiconductors.
As TV shops got more into audio service, and price pressures began to kill off service shops, this type of product became more prevalent. The early knock-offs were comical! How about a 2SD424 in a Motorola case that early 2N3055s came in. You know, the heavy raised bolt areas. These were immediately identifiable as Motorola parts. Then they started using the thin stamped Motorola cases (TO-3 style). TO-220 cased parts came next, but we already had horrible real parts (Texas Instruments made some nasty stuff back then).
For the most part, you could tell easily by the case. It is still a valuable thing to check. The lettering is another giveaway, and so is the manufacturer name. For example, in the past in the JIS system, a part number also signified who made the thing. An identically rated part made by someone else got a new number. Totally different from what happens in the JEDEC or Pro-electron system.
Buying from the least expensive source you can find also exposes you to an unreasonable risk concerning "remarked" (the proper term for this) semiconductors. Now to really muddy the water, a couple Chinese plants have opened that sell under their own name. They often produce discontinued parts, and I'll bet current parts as well. I can't speak to their quality, but I'd much rather be assured of top quality as my name goes onto each repair I do.
Hi tiefbassuebertr,
If you want to try and measure thermal transfer, be prepared for a lot of fun and a steep learning curve. Try measuring the B-E and B-C capacitance instead. Then measure the beta and any other easy spec to measure and confirm. The capacitance will give you some idea of the die size. Also map out the beta vs collector current and compare that to the data sheet.
For me, physical inspection and capacitance is normally enough. Anything else takes time, so a destructive test turns out to be less expensive (unless it's a pricy RF power transistor).
-Chris
All these fake parts are really old news - really old. At least now the major distributors are taking strong steps to keep the fakes out of the normal supply system. These fakes actually became noticed in the TV repair business. I think the first large scale copy was the Sony SG613 SCR. I think I have that part number right. Anyway, the TV service field is strongly price driven and staffed by mostly uneducated (to the level required in other fields) service people. There is also a high rate of very low moral ethics and down right thieves. In this environment, fake parts couldn't help but to be an extremely profitable business. Back in the 80's, there were people in New York operating semiconductor labelling machines. They weren't manufacturing semiconductors.
As TV shops got more into audio service, and price pressures began to kill off service shops, this type of product became more prevalent. The early knock-offs were comical! How about a 2SD424 in a Motorola case that early 2N3055s came in. You know, the heavy raised bolt areas. These were immediately identifiable as Motorola parts. Then they started using the thin stamped Motorola cases (TO-3 style). TO-220 cased parts came next, but we already had horrible real parts (Texas Instruments made some nasty stuff back then).
For the most part, you could tell easily by the case. It is still a valuable thing to check. The lettering is another giveaway, and so is the manufacturer name. For example, in the past in the JIS system, a part number also signified who made the thing. An identically rated part made by someone else got a new number. Totally different from what happens in the JEDEC or Pro-electron system.
Buying from the least expensive source you can find also exposes you to an unreasonable risk concerning "remarked" (the proper term for this) semiconductors. Now to really muddy the water, a couple Chinese plants have opened that sell under their own name. They often produce discontinued parts, and I'll bet current parts as well. I can't speak to their quality, but I'd much rather be assured of top quality as my name goes onto each repair I do.
Hi tiefbassuebertr,
If you want to try and measure thermal transfer, be prepared for a lot of fun and a steep learning curve. Try measuring the B-E and B-C capacitance instead. Then measure the beta and any other easy spec to measure and confirm. The capacitance will give you some idea of the die size. Also map out the beta vs collector current and compare that to the data sheet.
For me, physical inspection and capacitance is normally enough. Anything else takes time, so a destructive test turns out to be less expensive (unless it's a pricy RF power transistor).
-Chris