Interesting problem...with transistor marking

[km6xz]

Just a note to describe an interesting and frustrating repair on my bench. A GK 1001RB took out the output section, emitter resistors, drivers, pre-drivers, a couple zeners, the bias offset transistors and a bunch of fuse resistors.
I thought myself lucky to find the only 2SC5242 Toshiba power transistors in the city although there were several suppliers of the compliment 2SA1962's. All had the NPN's on back order. I replaced all the parts that were bad and tested the unit, worked fine up to the level of the second tier rails and it pulled increasing current without a load, no distortion, just higher current with increasing signal and no offset. The problem was traced to a pair of 2SC5242's.

I pulled them out and tested their curves on my Fairchild curve tracer....very high gain, like a Darlington. They ARE Darlingtons inside but the case is clearly marked C5242 Toshiba. I pulled all the rest they were normal transistors with identical markings. I checked the 8 extras I bought for stock and found 1 more that was very high gain. On closer inspection it seems they are slightly different in the polish of the metal heat transfer area, the good ones are polished shiny metal and fake versions are a dull grey, unpolished, not shiny at all.
I can't say I have ever run into that before.
Now all OK but wasted a few hours needlessly it.

[g1]

Guess they're not real Toshiba's then! Does the logo have any differences? To make money faking these they must be low power Darlingtons.
An autopsy of a fake and one of the dead originals would be interesting but you will probably be taking them back for a refund.

[Enzo]

This sucks.

Growning up, learning electronics, I just don't recall anyone making fake RCA tubes, y'know?

You have my sympathy.

[km6xz]

What I can't figure out is what is there to gain from counterfeiting transistors. They are not expensive and anyone buying them would be inclined to discover the switch. That is why I assumed they were miss-marked with perfectly respectable Toshiba logotype. The cast shell is identical with the same mold marks.
If one was going to all that trouble to fake something they would at least fake something that is valuable. I took a photo of them but it was in RAW mode so the file is 72mb. I'll post one tomorrow since it is 1 a.m. here and I need to go dance tonight before things get too crowded. I hate dance floors when they get too crowded to move, except vertically. By 3 a.m. they are.

[J M Fahey]

I need to go dance tonight before things get too crowded. I hate dance floors when they get too crowded to move, except vertically. By 3 a.m. they are.

Well, THAT'S something to be worried about, not crappy fake transistors

And hurry up!!!
Or you'll only get to dance with the "ugly" 3rd runner up at Miss Russia Beauty contest instead of the winner.

[km6xz]

Speaking of beauty, an acquaintance asked me to shoot a convention and competition for the beauty industry yesterday. I took two cameras, one with a 70-200 2.8 tele and the higher end pro camera(Nikon D800e 36mpx) with a 24-70 mounted and a 85 1.4G backup. It was held in a large sports arena with about 10,000 attendees from the surrounding countries. Boy, there must have been more beautiful ladies in that one building than anyway. I was asked by dozens of girls to do sessions with them.
For the makeup artist and hair competition there must have been 800 models alone in that section where the contestants were doing crazy hair styles and makeup on them. But many of the attendees were the most attractive.... I came back with 14gig of photos for my friend who is a rep for a major French cosmetics company. I did it on spec, if they use any in their publications or ads, I will get paid well.

[diydidi]

This sucks!! I also ran into some fake transistor blues this past weekend. Built Rod's P3A amplifier for my subwoofer project. Ordered some MJL21194/93 for this amp. (local)
Wire everything up. It works- for ten seconds that is. POOF! replace all the transistors on the board. Decided to crack open one of the MJL's with a hammer. Guess what! Fakes!!! Small silicon chip inside 2mmx 2mm. Glued down with that fake white glue. They fake them to the Tee. Even has ON semi logo.
Can you believe it??
Replaced outputs with genuine 2sc5200/2sa1943. Works great now!!!

[J M Fahey]

Post a picture, so we keep up to date with the mugshots.

[Steve Conner]

Yes, of the transistors and Miss Russia runner-up.

[beny86]

@km6xz although I was a bit surprised to read that somebody gave wrong (or fake) transistors. It just makes it difficult because darlingtons are actually not cheaper, they are actually more expensive than the conventional NPN transistors. It might actually be a factory error where they wrongly packaged some transistors which got shipped and passed in testing because of the same basic characteristics. That sounds a little bit of a more likely scenario to me. Secondly, I know this is not the right question for this thread but where exactly can you sell your photography?

[Steve Conner]

Even Darlingtons aren't expensive if they are rejects pulled out of the dumpster behind the semiconductor plant under cover of darkness.

Semiconductor fakery is now rampant, I recently got stung by a batch of DSP chips that were an old version remarked as the latest one, and some "400 amp ultrafast" IGBT modules that were really slower 300 amp devices remarked.

[Jazz P Bass]

And I also got burnt.
2SA1492 output transistors.
Sent the supplier an Email. "Are these parts genuine, old stock"
"Yup".
They didn't even make it to 50 volts on the variac rampup.

[km6xz]

@km6xz although I was a bit surprised to read that somebody gave wrong (or fake) transistors. It just makes it difficult because darlingtons are actually not cheaper, they are actually more expensive than the conventional NPN transistors. It might actually be a factory error where they wrongly packaged some transistors which got shipped and passed in testing because of the same basic characteristics. That sounds a little bit of a more likely scenario to me. Secondly, I know this is not the right question for this thread but where exactly can you sell your photography?

As Steve mentioned, fakes are usually rejects that get tossed of sold by the kilogram for scrap and remarked. I would advise against buying any eBAY parts that seem to be less than the "N" column price of the high volume parts distributors. Either avoid them or have a strict incoming test routine using a curve tracer that can handle the device's rated voltage and current. Otherwise you are gambling with a customer's piece of equipment.

Photography sales is hard now, you have to have the right image for the right client since stock pays so little and there are 16 billion other people supply stock companies. I shoot primarily for fun but have licensed images to cruise lines, tour companies, cosmetic distributors and back in my film days, made a lot in license royalties for candids in the recording studio or my kitchen/lounge area in the recording studio. those that paid the most were B&W mood fillers on album covers and liner notes. Since they were unavailable anywhere else, the income was really quite good, although at the time it was considered just hobby shooting and I did not attempt to cash in. But the art directors learned that they were available for most albums done so they were begging for them. I remember the largest license check for a single photo was $25k when the 6 month accounting was done. The labels did not care, it all came out of the artist points.
The 1980s brought in a trend of independent graphics art houses do the artwork more than the in-house art department of labels so I started a side business of doing album covers that was pretty successful. I had a printing company that was run by a couple who are fine art grads so they jumped at the chance to do higher end album work. The funny thing is that they tended to not use photos much so my candid studio photos ended up primarily in photo albums given the the artists at the end of projects.

Unless tied in with major ad or design houses, getting paid for photography is much much harder now that there is a very blurred line between amateurs willing to give it away for free and those trying to make a career of it. Just like all other crafts that have hobby potential, like music, recording or even repairing music equipment. In any case, being an effective networker and self promoter is much more important than the creations you produce.
There are a few niches that can generate hobby income, such as club shooting in some countries, can generate a few hundred dollars a night and if a name is developed, maybe $1k or more. But here again, getting started is hard because there are 1000 willing amateurs working for free for every skilled creative pro. Wedding photography is still the main income producer for pros. A wedding will be from $2k-10k and it is the only time in one's life where they are expected to pay for photos. Amateurs are eroding that also since a whole generation of clients have emerged who think a cell phone shot is just fine. If someone develops a unique style and a name, it becomes an international activity. I know one who is off around the world with a small crew almost every week doing high budget weddings. There are a lot of people who spend $500k or more on their weddings, mostly in other countries but that is not rare at all. There was one not long ago here where the event planning company here was contracted by the Merv Griffin Productions(after Griffin died) and the bill for creating and conducting the lavish wedding was $2.4m which was rumored to be 1/3th of the total price MGP charged. So there is money in such work but 1/10,000 can make a serious career out of it. The ratio of amateur to successful music careers is probably 1/1x10^6, very different than 50-60 years ago when the ratio was actually quite good.

[NZaudio]

This sucks!! I also ran into some fake transistor blues this past weekend. Built Rod's P3A amplifier for my subwoofer project. Ordered some MJL21194/93 for this amp. (local)
Wire everything up. It works- for ten seconds that is. POOF! replace all the transistors on the board. Decided to crack open one of the MJL's with a hammer. Guess what! Fakes!!! Small silicon chip inside 2mmx 2mm. Glued down with that fake white glue. They fake them to the Tee. Even has ON semi logo.
Can you believe it??
Replaced outputs with genuine 2sc5200/2sa1943. Works great now!!!

I have seen MJ15003 and similar types with 2 paralleled chips inside, mainly made in China, don't know where this will end. It's frustrating and time consuming.

[NZaudio]

Just a note to describe an interesting and frustrating repair on my bench. A GK 1001RB took out the output section, emitter resistors, drivers, pre-drivers, a couple zeners, the bias offset transistors and a bunch of fuse resistors.
I thought myself lucky to find the only 2SC5242 Toshiba power transistors in the city although there were several suppliers of the compliment 2SA1962's. All had the NPN's on back order. I replaced all the parts that were bad and tested the unit, worked fine up to the level of the second tier rails and it pulled increasing current without a load, no distortion, just higher current with increasing signal and no offset. The problem was traced to a pair of 2SC5242's.

I pulled them out and tested their curves on my Fairchild curve tracer....very high gain, like a Darlington. They ARE Darlingtons inside but the case is clearly marked C5242 Toshiba. I pulled all the rest they were normal transistors with identical markings. I checked the 8 extras I bought for stock and found 1 more that was very high gain. On closer inspection it seems they are slightly different in the polish of the metal heat transfer area, the good ones are polished shiny metal and fake versions are a dull grey, unpolished, not shiny at all.
I can't say I have ever run into that before.
Now all OK but wasted a few hours needlessly it.

I am new here and just saw your post coming up. Realized that you are in a group, had a look, liked it and joined the group if you all don't mind. I am originated from Germany but live in New Zealand.