I enclose a copy from ken Rockwells site, and I must admit I'd forgotten all about Tin Whiskers...
Aha! A reader sent me some NASA documentation about how severe is the problem with tin whiskers. The part abotu whiskers starts around page 41.
Tin whiskers are what mysteriously grow out of electronic parts that don't have enough lead in them to stop the problem. When these grow, they start shorting out circuits and causing all sorts of intermittent and permanent weird problems.
Solder is the soft white metal that holds all the parts together on circuit boards. Military and space electronics require at least 3% lead in their solder for precisely this reason. Normal solder is 40% lead, but optional RoHS proposals (that's the little "10" in circles on Nikon lenses and other products) demand no lead.
Consumer products makers love the RoHS/no lead standards, because these whiskers ensure that consumer electronics made without lead will all die in about ten years, so no one will get away with using old products, and have to keep buying new ones.
10 years is a perfect target life: it's long enough that no one blames the makers for deliberately building this in, and long enough that the maker has no warranty or good will problems. "Hey, it was ten years old, what do you expect?" Hey, I have plenty of thirty-year old and older audio and video products working here just perfectly, thank you.
If we all have to replace everything after 10 years, that's a lot of TVs sold. I have a two Visio TVs, a crappy brand, that died on me at 1 year and four years.
Reading the NASA paper, it may be a lot less than 10 years. All AF lenses work with electronics; they have been loaded with circuit boards and microprocessors and memory since the 1980s. Lose a circuit, and even a lens becomes useless.
No one ever died when their lens died, but the news media, sponsored by car ads, certainly doesn't want anyone learning what caused the Toyota unintended acceleration (UA) problems. Toyotas, like most modern cars, are drive-by-wire. Your gas pedal is nothing more than an input to a computer. Cars haven't had gas pedals connected to throttle valves since the 1980s. Toyotas use a variable resistor to encode gas pedal position, and feed that to the computer that does some math, and then controls the fuel injection and air induction systems itself for optimum efficiency.
The unintended accelerations were caused when a tin whisker in the throttle pedal encoder shorted it to make it seem as if the pedal was pushed all the way down!
See page 16, fourth paragraph: "Destructive physical analysis of this pedal assembly found tin whiskers, one of which had formed the resistive partial short circuit between the pedal signal outputs. A second tin whisker of similar length was also found in this pedal assembly that had not caused an electrical short. If a resistive short between the potentiometer accelerator pedal signal outputs exists, the system may be vulnerable to a specific second fault condition that could theoretically lead to UA."
I didn't read the whole report, but you might want to. You can use your browser to highlight "whisker." This isn't just me venting, it's NASA and NHTSA, the National Highway and Traffic Safety Administration.
So what does this all mean? Use real solder, and the problems go away. Buy RoHS products or use lead-free solder or products in your designs, and people die — far more than from any tiny amount of lead used in electronics products. Car batteries still have a zillion times more lead in them than we're discussing in solder.
This RoHS baloney is a clever plan by electronics makers to render all electronics products as disposable. RoHS was invented in China, obviously to ensure a steady demand for new electronics products, and adopted in Europe. The rest of the world is still free from this baloney, although many of the products we buy have these problems. Lead-free tin solder is crap.
I compliment car makers. Japanese cameras are run by computers, and due to sloppy design make themselves more difficult to use than a computer. Everything in a car, from the lights and beepers and gauges to the engines, brakes and transmissions are controlled by computers, and the levers, pedals and buttons are only inputs to those computers, but at least car makers make all this look the same from the driver's point of view as any other car from decades ago.
Camera makers ought to take this cue and make cameras that just go, instead of throwing up reams of code between us and making the camera take a picture.
If women knew just how unsafe these tin whiskers were making their cars, we'd have a riot on our hands. The media has done a great job of keeping this quiet. Looking at who pays for media (look at the ads), and now I know why this has been kept so quiet.
Here's NASA's page with a lot more about these whiskers.