I've been having early failures of 2sa1302 transistors sourced from MCM ( parent company "premier" also has Newark and Farnell). I opened some up and found the "super tiny" 2mm die hidden under a blob of white silicone glue. The real ones I bought from "Parts Express" over a year ago have about a 5mm die. Please email if you want photos and I will post them.
Toddy Audio said:
Bummer. Is MCM actually selling them as Toshiba parts or just 2SA1302 replacements?
Have you tried the OnSemi MJL1302s? We've used those and the genuine Toshibas and found the OnSemi parts to be more linear and more consistent than the Toshiba parts.
By the way, how'd you go about opening them up?
se
They look very similar to the genuine Toshiba parts, the main difference is the darker lettering and a "sanded" appearance to the metal backing. They are labeled and being sold as genuine "Toshiba" and "Japan".
If you want to look at the die (prefer blown transistor) you will have to crack the case open, easy way is to apply pressure to the sides of the plastic case (vice works good). Be careful and wear eye protection, the case will break (fly) into several pieces.
If you want to look at the die (prefer blown transistor) you will have to crack the case open, easy way is to apply pressure to the sides of the plastic case (vice works good). Be careful and wear eye protection, the case will break (fly) into several pieces.
How do you know that they are fakes? It can maybe be chips made in a newer silicone process? I admit though the silicone glue looks mysterious. 
Anyway I'm glad to be in Europe. Are there any firms here that deliver fakes? Never heard of one.
In Europe we have big distrubutors which buys directly from the manufactures. Fakes are out of the question! How does it work in USA? How are parts distributed?
Anyway I'm glad to be in Europe. Are there any firms here that deliver fakes? Never heard of one.
In Europe we have big distrubutors which buys directly from the manufactures. Fakes are out of the question! How does it work in USA? How are parts distributed?
When you do an online search for a component at MCM, you will sometimes get a couple of different manufacturers listed --a*n*d -- you will also sometimes see "MCM" in the manufacturer field. Typically, the "MCM" part is cheaper and in stock while the ones with an identified manufacturer may not be in stock, or have a minumum quantity (100, 1000 etc) or require a special order a*n*d have a higher price.
I've used "MCM" components in the past without a problem, so I can't say this means anything. Nonetheless, when ever practical I pick the component from a named manufacturer.
I've used "MCM" components in the past without a problem, so I can't say this means anything. Nonetheless, when ever practical I pick the component from a named manufacturer.
Toddy Audio said:
The green one's a 1302 as well?
Back when we were using the Toshibas, I seem to recall that they only used green for the PNP devices (i.e. 2SC3281) which while aesthetically rather yeccch, I thought was a good idea. If a 3281 accidentally got dropped into the 1302 bin (or vice versa) it would be quite obvious.
The OnSemis are all black and that micro laser printing (which is effectively black on black) is a ***** to read.
se
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