On 11/6/2014 8:15 PM, Louis Ciotti wrote:
Unfortunately this is going to be how things go in the future...
semiconductor companies are only going to produce items they can sell in
high volumes, and we are going to see more and more rigs put out of service
because the parts have become unobtainium... and with SDR rigs most likely
using (or will use) high pin count FPGAs with Ball-Grid footprints... what
a nightmare we are going to be in...
Transistors these days are a nightmare. Many of them are NOS (new old
stock) bought when companies that stocked or made them went out of
business or dropped the line. Lots of them ended up in China, but you
can find them sold all over the world.
Most of the new ones are "compatible" transistors made by Central
Semiconductor (the good ones) in China, and lots of little houses in
China, Korea, Taiwan, etc. They meet or exceed the spec of the original
transistor. Sometimes they are properly labeled, sometimes they are
label with whatever product ID you want, and sometimes they even have
the logo (or something that kind of looks like the logo) of the original
manufacturer.
For example, any NPN small signal transistor you get new is likely to be
a 2n2222a in a plastic case. No matter what you ask for, if you buy
100,000 it will be printed with the type number, logo and date code you
want. Only want 5? you can find someone on eBay selling them in small
quantities.
Same with FETs, The current "hot" FET is a J310. Want an MPF-102? You
might get NOS, you might get a relabeled J-310.
This happened with consumer tubes too just before their demise. The big
names bought them from the only company making them and relabeled them.
Sometimes they used a substitute.
Geoff.
--
Geoffrey S. Mendelson 4X1GM/N3OWJ
Jerusalem Israel.
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