"Ralph Mowery" wrote in message
k.net...
In article ,
says...



Oddly enough I've had to replace every 1N4002 diode used in one home
pinball game from the 1970s (Fischer's Sky Hawk) because they fail at
random. They appeared to be the world's cheapest diode - early Chinese?
- the body isn't a smooth cylinder rather it is lumpy.

I have to agree that diodes in monitors rarely fail, I can't recall the
last time we traced a problem to a faulty diode.


I never did understand why they make a series of diodes like the 1n4001
to 1n4007, each with a higher voltage rating. My only thought is they
make a batch like the microprocessors and test each one to see its
maximum rating and mark the lesser ones at a slightly lower price. I do
think the 1n4007 may be a slightly different kind of makeup than the
others. Another thing is odd voltage cpacitors like a 63 volt unit.
Why not just 60 or 70 or even 65 due to the large tollorance of them.

Last time I ordered diodes - all the PIV grades were the same price, I just
ordered the highest grade in a larger quantity.

I have absolutely no idea how they grade production and marketing.