This one experienced 550 VAC. It was a piece of wire disguised as a triac. The mag coil was open but had shorted turns and had overheated.
The entire amp was a mess, and the other caps had exploded and vented all over the place. In short, it was a mess with little cap cans all over the place.
I don't know how long it took for the fuses to open, but it was clearly far too long. The damage was so severe it was funny, and there was no discussion of rebuilding it. Possible? Yes, the boards were okay. Replacement was less expensive.
-Chris
The entire amp was a mess, and the other caps had exploded and vented all over the place. In short, it was a mess with little cap cans all over the place.
I don't know how long it took for the fuses to open, but it was clearly far too long. The damage was so severe it was funny, and there was no discussion of rebuilding it. Possible? Yes, the boards were okay. Replacement was less expensive.
-Chris
I have IRF610 mosfets who I had ordered past year but now want to use, unfortanely fakes, because I can with some moisture rub the tekst very easely from the transistor leaving it without tekst.
There are incredible much fakes, it get's time something is done about it, the yellow danger get's out of hand.
There are incredible much fakes, it get's time something is done about it, the yellow danger get's out of hand.
It is far past time however no sign anything will be done. I am fighting with AliExpress right now over LM358 types (measured 40 nV/rtHz) relabeled and sold as OPA1612. They are obviously fake and counterfeit but AliExpress rejects the dispute and says "invalid" for fake and "invalid" for counterfeit.
Not much will be done about the fake problem when they get away with this (absolute bold faced lies) and there are zero consequences for them. And with AliExpress and Ebay allowing the negative feedback to be deleted this will just continue.
Well I had to go a few more rounds with them. Eventually I made a video (testing them for noise). That was a pain. I had to restart the video a couple of times since I don't have a camera stand of any sort and it is very hard to operate test sockets and equipment with one hand.
Eventually I prevailed however I have attached some of the nonsense they said regarding them being the OPA1612 model described and not being fake/counterfeit. They apparently want a statement from Texas Instruments/brand owner that they are fake OPA1612. In other words they will never admit they are fake/counterfeit.
Basically AliExpress refuses to admit that fakes are fake and that counterfeits are counterfeit. They can not seem to be honest or reasonable in that regard.
It is a real waste of time and very aggravating. Previously I have bought genuine from that seller and I needed more due to the huge number of op-amps in the E-MU 1616m, E-MU 1820m and Digidesign 003R racks/docks. AliExpress seems to be getting more difficult to deal with. I used a microscope with a digital camera to take a picture of the differences (including the faint horizontal sand paper lines from removing the original markings) and AliExpress says that they can't see the problem in the photos.
The problem with buying at spot prices is that you really need to be there to examine and test before paying.
Also AliExpress claimed that the seller provided proof they were genuine when in fact the seller provided no evidence and instead said that such differences were normal. I bet the fake sellers love the fact that the return shipping (within 10 days) with tracking from the US to China costs more than the product costs.
Eventually I prevailed however I have attached some of the nonsense they said regarding them being the OPA1612 model described and not being fake/counterfeit. They apparently want a statement from Texas Instruments/brand owner that they are fake OPA1612. In other words they will never admit they are fake/counterfeit.
Basically AliExpress refuses to admit that fakes are fake and that counterfeits are counterfeit. They can not seem to be honest or reasonable in that regard.
It is a real waste of time and very aggravating. Previously I have bought genuine from that seller and I needed more due to the huge number of op-amps in the E-MU 1616m, E-MU 1820m and Digidesign 003R racks/docks. AliExpress seems to be getting more difficult to deal with. I used a microscope with a digital camera to take a picture of the differences (including the faint horizontal sand paper lines from removing the original markings) and AliExpress says that they can't see the problem in the photos.
The problem with buying at spot prices is that you really need to be there to examine and test before paying.
Also AliExpress claimed that the seller provided proof they were genuine when in fact the seller provided no evidence and instead said that such differences were normal. I bet the fake sellers love the fact that the return shipping (within 10 days) with tracking from the US to China costs more than the product costs.
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Yes, they do look like the real deal.
Normally your best indicator is the place where you bought them. Normal distribution channels are always the first choice. Other vendors that are known to be on the level next. After that it is a total lottery with no reasonable expectation you aren't getting fakes.
I will say that laser etched markings are not normal for most transistors, older numbers in particular and almost always guarantee the part is a fake. Only recently manufactured parts may have laser etching.
-Chris
Normally your best indicator is the place where you bought them. Normal distribution channels are always the first choice. Other vendors that are known to be on the level next. After that it is a total lottery with no reasonable expectation you aren't getting fakes.
I will say that laser etched markings are not normal for most transistors, older numbers in particular and almost always guarantee the part is a fake. Only recently manufactured parts may have laser etching.
-Chris
Just FYI about physically very realistic looking fakes of just about any part number including low cost TIP35C and TIP36C:
Someone else bought the same fake TIP35C and TIP36C that I had bought and took the attached picture. (Fakes in the middle.) Tiny die. But extremely good looking lead frame and marking. The lead frame might look so good because genuine lead frames are now made in the country that made the fakes.
I have also had fake 2SC5200/2SA1943, 2SC5198/2SA1941, TIP41/TIP42. TIP142/TIP147, D1047/B817, 2SD669/2SB649.
So I am only using genuine Toshiba and Sanken from Mouser and Digikey now. But the Sanken are disappearing (EOL).
Someone else bought the same fake TIP35C and TIP36C that I had bought and took the attached picture. (Fakes in the middle.) Tiny die. But extremely good looking lead frame and marking. The lead frame might look so good because genuine lead frames are now made in the country that made the fakes.
I have also had fake 2SC5200/2SA1943, 2SC5198/2SA1941, TIP41/TIP42. TIP142/TIP147, D1047/B817, 2SD669/2SB649.
So I am only using genuine Toshiba and Sanken from Mouser and Digikey now. But the Sanken are disappearing (EOL).
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Right. I just wanted everyone to know just how realistic the lead frames, packages and laser marking looks now (on the fakes). I suspect at least the lead frames are from the same supplier as genuine parts. The packaging/molding/laser marking might also be done now in the same facilities as genuine parts. So spotting fakes is very difficult visually now. You need to do measurements which 9x% of buyers do not do.
I am quite certain that indeed they are genuine ... the precision broken printing on the type number is one of the clues. This was used by one of the major manufacturers in the 1970s (and looking at the leads, I'd reckon those have been sitting around that long!)
The electronics stores at the Univ. of Essex in England in the early 70s sold parts to students and I bought many transistors there. They used this same kind of precision broken painted markings.
They could be either Mullard (Philips) or Fairchild ... although Fairchild usually included their stylized f on the case.
The BC550 is a silicon epitaxial transistor in the BC547, 548, 549, 550 family. They are essentially epoxy cased versions of the Mullard metal cased BC107, 108, 109 range. They were generally multipurpose ... the 549 had the best gain and frequency response in the group, but as a result you had to watch out for spurious oscillations! The Vce of the group varied but beware that some manufacturers varied the higher Vce ratings compared to others.
The C on the next line is the gain hfe group .... A, B, C ... with C being the highest. For example, it's not wise to replace say a 548 A with a 548 C ... and in stereo amps, you want the same gain group in both channels!
There are lots of similar transistors with variants on the name ... some changed with encapsulation ... such as the BC247... which was Mullard's "lokfit" pinout designed to hold them in a PCB for wave soldering.
So, some of the story of the BC..6, ..7, ..8 etc transistors.
Somewhere in one of my stuff in the workshop, I have some BC 548s that look just like yours with the same printing and all.
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Hello, I just purchased some components from newark.com and I am not happy at all with what I got as ksa992FTA. I attached a picture of the just ordered transistors and another picture of some KSC1845FTA I had purchased a couple of years ago from Digikey/Mouser. Both of these are suppose to be onsemi .
Gabe
Gabe
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Newark.com is a trustworthy supplier. Something very wrong would have happened in their supply chain to have received counterfeits. They would have received these direct from onsemi.
onsemi have manufacturing plants all over the place, each with subtly different moulds and labelling gear. So you do get variants.
Is there some other reason you think they are fake.
onsemi have manufacturing plants all over the place, each with subtly different moulds and labelling gear. So you do get variants.
Is there some other reason you think they are fake.
My suspicion about these transistors is based only on the imprint , no measurements were done yet.
I do believe that the KSC1845FTA I already had are Fairchild and the ksa992FTA transistors I just got from newark.com are Onsemi. That's how I explain the totally different imprint . Can anyone post pictures of their transistors?
Thanks
I do believe that the KSC1845FTA I already had are Fairchild and the ksa992FTA transistors I just got from newark.com are Onsemi. That's how I explain the totally different imprint . Can anyone post pictures of their transistors?
Thanks
OnSemi took over Fairchild, I think.
They might have changed the manufacturing location, markings and so on.
And integrated locations, so similar parts are made in the same plant.
That might be the reason for the variation. Another is against fakes, the markings and batch numbers might change regularly.
They might have changed the manufacturing location, markings and so on.
And integrated locations, so similar parts are made in the same plant.
That might be the reason for the variation. Another is against fakes, the markings and batch numbers might change regularly.
I just took these this morning, the KSC1845FTA are ON from Newark. The KSA992FBTA are ON from Mouser. Both bought in the last 90days.
